System Component Tests

7/25/2019 System Component Tests

1/64

I - SYSTEM/COMPONENT TESTS

2000 Mazda MPV

2000 ENGINE PERFORMANCE System & Component Testing

Miata, Millenia, MPV, Protege & 626

INTRODUCTION

Before testing separate components or systems, performprocedures in BASIC DIAGNOSTIC PROCEDURES article. Since manycomputer-controlled and monitored components set a diagnostic troublecode if they malfunction, also perform procedures in appropriate SELF-DIAGNOSTICS article.

NOTE: Testing individual components does not isolate shorts or

opens. Perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

AIR INDUCTION SYSTEMS

AIR CHARGING PRESSURE CONTROL (MILLENIA 2.3L)

Lysholm Compressor Remove drive belt. Rotate compressor shaft by hand.Compressor shaft should rotate smoothly. Check for cracks or damage.Replace compressor as necessary.

Charge Air Cooler (Intercooler) Remove charge air cooler and inspect for cracks, restrictionor damage. Replace as necessary.

Charge Air Cooler By-Pass (System Check) Start engine and verify charge air cooler by-pass actuatorrod is retracted. See Fig. 1. Increase engine speed to 4100 RPM.Actuator rod should extend. If actuator rod does not operate asdescribed, check for leaking vacuum hose, faulty vacuum pump, chargeair cooler, by-pass solenoid valve, faulty shutter valve or faultyactuator.

Charge Air Cooler By-Pass Actuator Remove vacuum hose from air cooler by-pass actuator. SeeFig. 1. Connect vacuum pump to actuator and apply 7.4 in. Hg ofvacuum. Actuator rod should retract. If actuator does not operate,

replace actuator.

Air By-Pass Valve (ABV) Actuator Remove ABV actuator. See Fig. 1. Verify air does not flowfrom port "A" to port "B". See Fig. 2. Connect a vacuum pump to ABVactuator port "C" and apply 10 in. Hg of vacuum. Air should flow fromport "A" to port "B". Airflow should increase as vacuum to port "C" isincreased. If ABV actuator does not operate as specified, replace ABVactuator.

Charge Air Cooler By-Pass Solenoid Valve Remove charge air cooler by-pass solenoid valve. See Fig. 1.Apply air pressure to solenoid valve port "B". See Fig. 3. Air fromport "B" should flow from "C" only. Using jumper wires, apply batteryvoltage to solenoid valve terminals. Apply air pressure to solenoid


2/64

valve port "A". Air should flow from port "B" only. Replace solenoidvalve as necessary.

Air By-Pass Valve (ABV) Vacuum Solenoid Valve Remove ABV vacuum solenoid valve. See Fig. 1. Apply airpressure to port "A" of ABV solenoid valve. See Fig. 4. Air should notflow from port "B". Apply battery voltage to ABV vacuum solenoid valveterminals. Air should flow from port "B". Replace ABV vacuum solenoidvalve as necessary.

Air By-Pass Valve (ABV) Vent Solenoid Valve 1) Remove ABV vent solenoid valve. See Fig. 1. Apply airpressure to port "A" of ABV vent solenoid valve. See Fig. 5. Airshould flow from ports "B" and "C". Apply air pressure to port "B".Air should flow from port "C". Replace ABV vent solenoid valve asnecessary. If ABV vent solenoid valve operates as specified, go tonext step. 2) Using jumper wires, apply battery voltage to ABV vent

solenoid valve terminals. Apply air pressure to port "A". Air shouldflow from port "B" only. Apply air pressure to port "B". Air shouldnot flow from port "C". Replace ABV vent solenoid valve as necessary.

Fig. 1: Identifying Air Charging Pressure Control SystemComponents (Millenia 2.3L)Courtesy of Mazda Motors Corp.


3/64

Fig. 2: Identifying ABV Actuator Ports (Millenia 2.3L)Courtesy of Mazda Motors Corp.

Fig. 3: Identifying Charge Air Cooler By-Pass Solenoid ValvePorts (EGR Boost Sensor Solenoid & MAP Sensor Solenoid Valves Are


4/64

Similar)Courtesy of Mazda Motors Corp.

Fig. 4: Identifying ABV Vacuum Solenoid Valve Ports (Millenia 2.3L)Courtesy of Mazda Motors Corp.

Fig. 5: Identifying ABV Vent Solenoid Valve Ports (Millenia 2.3L)Courtesy of Mazda Motors Corp.

INTAKE MANIFOLD RUNNER CONTROL (IMRC) - MPV


5/64

System Check Start engine, and let idle. Actuator should not operate atengine speeds of less than 3300 RPM. Raise engine speed. Actuatorshould operate at engine speeds of more than 3300 RPM. Using scantool, check for DTCs. If DTC P1512, P1518 or P1520 are present, seeappropriate test in SELF-DIAGNOSTICS - MPV. If no DTCs are present,start engine. Using scan tool, select SIMULATION TEST. Turn IMRCactuator on and off. If actuator operation is heard, check actuatorcable tension and condition. Repair as necessary. If actuatoroperation is not heard, check Green/White wire between main relay andactuator terminal No. 2. Check Black/White wire between actuatorterminal No. 3 and ground. Check Black/Red wire and Black/Yellow wirebetween actuator terminal No. 1 and PCM terminal No. 42. Repair asnecessary. If no problem is found, replace actuator.

VARIABLE INERTIA CHARGING SYSTEM (VICS) - PROTEGE 1.8L

NOTE: For VICS component locations, see appropriate vacuum diagram

in VACUUM DIAGRAMS article.

System Check Connect tachometer to engine. Start engine, and let idle.Shutter valve actuator rod should be extended at idle. See Fig. 6.Gradually increase engine speed to 5000 RPM and ensure actuator rodretracts. If system actuator does not operate as specified, check forvacuum leaks. If no vacuum leaks are detected, check shutter valve andshutter valve solenoid.

Fig. 6: Checking Shutter Valve ActuatorCourtesy of Mazda Motors Corp.

Solenoid Valve Remove solenoid valve. Apply air pressure to port "B". SeeFig. 7. Air should flow from "C". Using jumper wires, apply batteryvoltage to solenoid valve terminals. Apply air pressure to port "B".Air should flow from port "A". Replace solenoid valve as necessary.


6/64

Fig. 7: Identifying Solenoid Valve PortsCourtesy of Mazda Motors Corp.

Shutter Valve Actuator Disconnect vacuum hose from shutter valve actuator. SeeFig. 6. Connect vacuum pump to actuator. If rod does not move,disconnect rod and check rod and valve for freedom of movement. Applyvacuum and verify shutter valve rod retracts. Replace as necessary. DONOT adjust shutter valve stopper bolt.

Vacuum Chamber Remove vacuum chamber. Visually inspect vacuum chamber for

clogging, cracks and damage. Apply air pressure to port "A" and ensureair flows from port "B". See Fig. 8. Apply air pressure to port "B".Air should flow from port "A". Replace vacuum chamber as necessary.

Fig. 8: Testing Vacuum Chamber (Protege 1.8L)Courtesy of Mazda Motors Corp.

VARIABLE INERTIA CHARGING SYSTEM (VICS) - MIATA


7/64

NOTE: For VICS component locations, see appropriate vacuum diagram in VACUUM DIAGRAMS article.

System Check Connect tachometer to engine. Start engine, and let idle.Shutter valve actuator rod should be extended at idle for 5 seconds.After 5 seconds, Shutter valve actuator rod should retract. Graduallyincrease engine speed to 5250 RPM and ensure actuator rod extends. Ifsystem actuator does not operate as specified, check for vacuum leaks.If no vacuum leaks are detected, check for DTC P1523. Diagnose andrepair as necessary. If DTC P1523 is not present, use scan tool inSIMULATION TEST mode to actuate solenoid valve. Listen to solenoidwhile actuating with scan tool. If solenoid clicks, check vacuumactuator, vacuum chamber and vacuum lines. If solenoid does not click,check solenoid. Repair or replace as necessary.

Actuator Check Disconnect vacuum hose. Using vacuum pump, apply vacuum to

actuator. See VICS OPERATION table. If actuator does not operateproperly, replace actuator and recheck.

VICS OPERATION

Vacuum Rod Position

.4 ....................................................... Extended

.4-1.1 .......................................... Starts To Retract7.5 ..................................................... Retracted

Solenoid Check Remove solenoid. Check flow between solenoid valve port "B"and "C". See Fig. 3. Flow should exist. Using jumper wires, connect

battery voltage to solenoid terminal "A" and battery ground toterminal "B". Check flow between solenoid valve port "A" and "B". Flowshould exist. If flow is not as specified, replace solenoid.

VARIABLE RESONANCE INDUCTION SYSTEM (VRIS) - MILLENIA 2.5L & 626 2.5L

System Check 1) Start engine. Check Variable Resonance Induction System(VRIS) shutter valve actuator rod positions. For 626, see VACUUMDIAGRAMS article. For Millenia, see Fig. 9. On all models, rods shouldnot be pulled. If shutter valve actuator rods are not pulled, go tostep 3). If shutter valve actuator rods are pulled, go to next step. 2) Turn ignition off. Connect New Generation Star (49 T0880A0) scan tool to Data Link Connector (DLC). DLC is located under left

side of instrument panel, right of steering column. Check forDiagnostic Trouble Codes (DTCs). See appropriate SELF-DIAGNOSTICS -INTRODUCTION article. If any DTCs are present, repair as necessary. Ifno DTCs are present, go to next step. 3) Start engine and run at idle. Using scan tool, selectSIMULATION TEST and turn both VRIS solenoid valves on. Listen forsolenoid clicking noise. If both solenoids click, check shutter valveactuators. If solenoids do not click, check solenoid valves. 4) Start engine and operate at idle. Check operation ofshutter valve actuators No. 1 and 2 at specified engine speed. SeeVRIS RPM SPECIFICATIONS (MILLENIA 2.5L & 626 2.5L) table. If actuatorsdo not operate as specified, check for DTCs. See appropriate SELF-DIAGNOSTICS - INTRODUCTION article. Repair as necessary. If no DTCsare present, check VRIS components and Throttle Position (TP) sensor.


8/64

VRIS RPM SPECIFICATIONS (MILLENIA 2.5L & 626 2.5L)

RPM Position

Millenia 2.5L Shutter Valve No. 1 Less Than 3750 ......................................... Closed 3750-6250 ................................................ Open More Than 6250 ......................................... Closed Shutter Valve No. 2 Less Than 4250 ......................................... Closed 4250-6250 ................................................ Open More Than 6250 ......................................... Closed626 2.5L Shutter Valve No. 1 Less Than 3250 ......................................... Closed 3250-6250 ................................................ Open More Than 6250 ......................................... Closed

Shutter Valve No. 2 Less Than 4250 ......................................... Closed 4250-6250 ................................................ Open More Than 6250 ......................................... Closed

Check Valve Remove check valve. For 626, see VACUUM DIAGRAMS article. ForMillenia, see Fig. 9. On all models, apply air pressure to port "A"(White port) of check valve. Air should flow from port "B". Apply airpressure to port "B" (Green port) of check valve. Air should not flowfrom port "A". Replace check valve as necessary.

Shutter Valve Actuators Disconnect vacuum hose from shutter valve actuators No. 1 and

2. For 626, see VACUUM DIAGRAMS article. For Millenia, see Fig. 9. Onall models, connect vacuum pump to actuator. Apply vacuum to eachactuator separately and verify shutter valve rod retracts. Ensure bothshutter valves move freely. Replace actuator as necessary.

Solenoid Valve Remove solenoid valve. Apply air pressure to port "B". SeeFig. 7. Air should flow from "C". Using jumper wires, apply batteryvoltage to solenoid valve terminals. Apply air pressure to port "B".Air should flow from port "A". Replace solenoid valve as necessary.

Vacuum Chamber Millenia 2.5L is equipped with one vacuum chamber. 626 2.5Lis equipped with 2 vacuum chambers. Remove vacuum chamber. Visuallyinspect vacuum chamber for clogging, cracks and damage. Replace asnecessary.


9/64

Fig. 9: Identifying Variable Resonance Induction SystemComponents (Millenia 2.5L)Courtesy of Mazda Motors Corp.

VARIABLE TUMBLE CONTROL SYSTEM (VTCS) - PROTEGE 1.6L

System Check For system check, see appropriate test in SELF-DIAGNOSTICS -PROTEGE 1.6L article.

One Way Check Valve Check Remove one way check valve. Blow in valve into direction ofarrow. Air should flow. Blow into valve in opposite direction. Airshould not flow. If flow is not as specified, replace valve.

Shutter Valve Actuator Check Disconnect vacuum hose from actuator. Connect a vacuum pumpto actuator. Watch actuator rod and apply vacuum to actuator. SeeSHUTTER VALVE ACTUATOR CHECK table. If actuator does not operate asspecified, replace actuator. If system is not working properly butactuator is okay, check vacuum lines.

SHUTTER VALVE ACTUATOR CHECK (PROTEGE 1.6L)

Vacuum in. Hg (kPa) Actuator


10/64

Less than -20 (-6.7) ..................................... Extended-20 (-6.7) ................................................. Moving-29 (-8.6) .............................................. Retracted

NOTE: Perform VTCS solenoid check only when directed by SELF-DIAGNOSTICS testing.

VTCS Solenoid Check Remove solenoid. Check solenoid airflow. See Fig. 10. Applybattery voltage to solenoid. Check airflow. See Fig. 10. If solenoidis okay, check vacuum lines. Repair as necessary. If no problem isfound, Check for open or short in wiring. See appropriate wiringdiagram in WIRING DIAGRAMS article. Repair as necessary.

Fig. 10: Testing VTCS Solenoid OperationCourtesy of Mazda Motors Corp.

COMPUTERIZED ENGINE CONTROLS


11/64

POWERTRAIN CONTROL MODULE (PCM)

Ground Circuit Checks 1) Using an ohmmeter, check ground circuits to PCM forcontinuity to ground. See appropriate wiring diagram in appropriatewiring diagram in WIRING DIAGRAMS article to determine PCM groundterminals. See PCM LOCATIONS table. If continuity does not exist,repair open circuit to ground. 2) Using a voltmeter, touch negative lead to a good ground.Touch positive lead to each ground terminal. With vehicle running,voltmeter should indicate less than one volt. If voltage reading ismore than one volt, check for open circuit, corrosion, or looseconnection on ground lead.

Power Circuit Checks 1) Using a voltmeter, check for battery voltage between PCMconstant battery power terminals and ground. See appropriate wiring

diagram in WIRING DIAGRAMS article to determine PCM power terminals.See PCM LOCATIONS table. If battery voltage is not present, check PCMpower supply fuse. If fuse is okay, check for open in power supply orPCM wiring. 2) Turn ignition on. Using a voltmeter, check for batteryvoltage between PCM ignition power terminals and ground. If batteryvoltage is not present, check power supply fuse(s). If fuse is okay,check for an open in wiring between fuse and PCM, or check for adefective ignition switch. 3) Connect voltmeter between ground and PCM start (crank)signal terminal. Turn ignition switch to START position. Batteryvoltage should be present between PCM start terminal and ground onlywhen ignition switch is in START position. If voltage is not present,check fuse(s). If fuse is okay, check for open circuit in wiringharness between fuse and PCM. If wiring harness is okay, check for a

defective ignition switch.

PCM LOCATIONS

Application Location

Miata ............................ Below Center Of Instrument PanelMillenia ......................... Below Center Of Instrument PanelMPV .............................. Below Center Of Instrument PanelProtege .......................... Below Center Of Instrument Panel626 ................................. Below Front Of Center Console

Reference Voltage (MPV) 1) Disconnect appropriate sensor connector where voltage

problem is suspected. Turn ignition on. Check voltage between harnessconnector reference voltage terminal and ground terminal. If voltageis 6 volts or less, go to next step. If voltage is more than 6 volts,go to step 3). 2) Check voltage at battery terminals. If battery voltage ismore than 10.5 volts, go to next step. If battery voltage is 10.5volts or less, check charging system. 3) Turn ignition off. Check voltage between positive batteryterminal and sensor harness connector ground terminal. If voltage ismore than 10.5 volts and within 1 volt of battery voltage, go to nextstep. If battery voltage is 10.5 volts or less, or difference betweenmeasured voltage and battery voltage is more than 1 volt, go to step10). 4) Turn ignition on. Using scan tool, check ECT PID. If scantool cannot access PID, go to next step. If scan tool can communicate


12/64

with PCM and access PID, go to step 7). 5) Turn ignition off. Disconnect TP sensor, EGR boost sensor,FTP sensor and PCM. Turn ignition on. Check voltage between PCMharness connector terminals 71 and 97 (+) and 24, 51, 76, 77 and 103(-). If voltage is more than 10.5 volts, go to next step. If voltage is10.5 volts or less, repair open circuit between main relay and PCMterminals 71 and 97. 6) Turn ignition off. Check resistance between harnessconnector terminal 90 (Pink/Blue wire) and terminals 24, 51, 76, 77and 103. If resistance is more than 10,000 ohms, recheck referencevoltage. See step 6). If resistance is 10,000 ohms or less, repairshort to ground on Pink/Blue wire. 7) Turn ignition off. Disconnect suspect sensor and PCM.Check resistance between harness connector terminal 90 (Pink/Bluewire) and suspect sensor harness connector reference voltage terminal.If resistance is less than 5 ohms, recheck reference voltage. See step6). If resistance is 5 ohms or more, repair open circuit on Pink/Bluewire.

8) Reconnect suspect sensor. Turn ignition on. Using scantool, check ECT PID. If scan tool can access PID, go to next step. Ifscan tool cannot communicate with PCM and access PID, go to step 12). 9) If DTCs for two or more sensors listed are present, go tonext step. If DTC(s) for only one sensor listed is present, repairopen in ground circuit for suspect sensor.

* ECT sensor (DTCs P0116, P0117, P0118, P0125). * EGR boost sensor (DTCs P0106, P0107, P0108). * FTP sensor (DTCs P0451, P0452, P0453, P0454). * Front HO2S (DTCs P0134, P0154, P1170, P1173). * Middle HO2S (Federal only) (DTCs P0140, P1169). * Rear HO2S (California only - DTCs P0138, P0140, P0158, P1160). * Rear HO2S (Federal only - DTCs P0144, P0146).

* IAT sensor (DTCs P0111, P0112, P0113). * TP sensor (DTCs P0122, P0123, P1122, P1123).

10) Turn ignition off. Disconnect scan tool and PCM. Checkresistance of sensor ground circuit between harness connector terminal91 (Brown/Yellow wire) and suspect sensor harness connector groundterminal. If resistance is less than 5 ohms, reconnect all componentsand return to appropriate DTC test. If resistance is 5 ohms or more,repair open circuit on Brown/Yellow wire. 11) Turn ignition off. Disconnect PCM connector. Checkresistance between battery negative terminal and PCM harness connectorterminals 24, 51, 76, 77 and 103. If resistance is less than 5 ohms,go to next step. If resistance is 5 ohms or more, repair open onground circuit. 12) Turn ignition off. Check resistance between harnessconnector ground terminal of each sensor listed and ground. If anyresistance is more than 5 ohms, repair open ground circuit. Ifresistance is less than 5 ohms on all terminals, grounds are okay.Recheck reference voltage. See step 6).

* TP sensor. * EGR boost sensor. * FTP sensor. * ECT sensor. * IAT sensor. * Front HO2S. * Middle HO2S (Federal only). * Rear HO2S.

13) Turn ignition off. Disconnect TP sensor, EGR boost


13/64

sensor, FTP sensor and PCM. Turn ignition on. Check voltage between TPsensor harness connector reference voltage terminal and batterynegative terminal. If voltage is .5 volt or more, repair referencevoltage circuit short to power. If voltage is less than .5 volt,recheck reference voltage. See step 6). 14) Clear DTCs and recheck symptom. If no problem is present,continue diagnosis. If reference voltage fault is present, check forservice bulletins and on-line information. Repair as necessary. Iffault is still present, replace PCM.

ENGINE SENSORS & SWITCHES

BRAKELIGHT SWITCH

Disconnect brakelight switch connector. Using ohmmeter, checkcontinuity between brakelight switch terminals. With brake pedalreleased, continuity should not exist. With brake pedal depressed,

continuity should exist. If continuity is not as specified, replacebrakelight switch.

CAMSHAFT POSITION (CMP) SENSOR

Miata & Protege 1.6L 1) Remove and inspect camshaft position sensor. Clean off anymetal particles or shavings. Reinstall sensor. 2) Connect scan tool. Start engine. Using scan tool, entervehicle info and connect scan tool leads to PCM. SeeCMP/PCM TERMINAL IDENTIFICATION (MIATA & PROTEGE 1.6L) table. SelectDIGITAL MEASUREMENT SYSTEM, then FREQUENCY METER. Press link key toselect RPM PID. Select PID/DATA MONITOR, then PCM. Press START. 3) Frequency meter should be displayed. Ensure thresholdvoltage is 2 volts and DC voltage is selected. Frequency should match

specifications. SeeCMP FREQUENCY SPECIFICATIONS (MIATA & PROTEGE 1.6L) table. 4) Change scan tool threshold voltage to 6 volts. Ensurefrequency is 0 Hz. If frequency is out of specifications, check wiringfor open or short circuit. Check camshaft pulley for damage. Repair asnecessary.

CMP/PCM TERMINAL IDENTIFICATION (MIATA & PROTEGE 1.6L)

Test Connection PCM Terminal

Miata Positive Lead ................................................ 2H Negative Lead ................................................ 3CProtege 1.6L

Positive Lead ................................................ 85 Negative Lead ............................................... 103

CMP FREQUENCY SPECIFICATIONS (MIATA & PROTEGE 1.6L)

RPM (1) Frequency

650-750 (Protege 1.6L Idle) ................................. 16-18750-850 (Miata Idle) ........................................ 18-221000 ........................................................... 252000 ........................................................... 503000 ........................................................... 75

(1) - Measured in Hertz (Hz).


14/64

Millenia 2.3L 1) CMP sensor is located on right front of engine. Remove CMPsensor, leaving electrical connector connected. Using analog voltmeter(or oscilloscope), connect negative lead to CMP sensor ground (CMPbody or Black/Blue wire). 2) With positive voltmeter lead, backprobe Blue/Red wire atCMP connector. Turn ignition on. Rotate CMP shaft and observe voltagereading. Voltmeter should indicate a voltage pulse (5 volts) perrevolution. Replace CMP sensor as necessary.

Millenia 2.5L 1) CMP sensor is located inside of distributor. Removedistributor, leaving electrical connector connected. Using analogvoltmeter (or oscilloscope), connect negative lead to CMP sensorground (CMP body or Black/Blue wire). 2) With positive voltmeter lead, backprobe Yellow/Blue wire

at CMP connector. Turn ignition on. Rotate CMP shaft and observevoltage reading. Voltmeter should indicate one voltage pulse (5 volts)per revolution. Replace distributor as necessary.

MPV Disconnect CMP sensor connector. Check resistance betweensensor terminals. If resistance is not 292-385 ohms, replace sensor.If resistance is 292-385 ohms, disconnect PCM connector. Connectbreakout box to harness connector. Leave PCM disconnected. Checkcontinuity of Blue wire and Blue/Green wire between sensor harnessconnector terminal "A" and breakout box terminal No. 85. Checkcontinuity of Yellow wire between sensor harness connector terminal"B" and breakout box terminal No. 86.

Protege 1.8L

Disconnect CMP sensor harness connector. CMP sensor islocated in timing belt cover, in upper front of engine. Usingohmmeter, measure resistance between component terminals. Resistanceshould be 950-1250 ohms. Replace as needed. If sensor is okay, checkfor open or short circuit in wiring between sensor and PCM. Repair asnecessary.

626 2.0L Disconnect CMP sensor harness connector. CMP sensor islocated in timing belt cover, in upper front of engine. Usingohmmeter, measure resistance between component terminals. Resistanceshould be 950-1250 ohms. Replace as needed.

626 2.5L Disconnect CMP sensor harness connector. CMP sensor islocated next to right timing pulley. Using ohmmeter, measureresistance between component terminals. Resistance should beapproximately 550 ohms. Replace as needed.

CLOSED THROTTLE POSITION SWITCH

Millenia Closed throttle position switch is part of Throttle Position(TP) sensor. To test closed throttle position switch, check TP sensorcontinuity. See THROTTLE POSITION SENSOR (TP) in ON-VEHICLEADJUSTMENTS article. Check TP sensor adjustment before replacing TPsensor.

CLUTCH SWITCH (M/T)


15/64

Miata, Protege & 626 Disconnect clutch switch connector. Using ohmmeter, checkcontinuity between switch terminals. With clutch pedal depressed,continuity should exist. With clutch pedal released, continuity shouldnot exist. If continuity is not as specified, replace clutch switch.

CRANKSHAFT POSITION (CKP) SENSOR

1) CKP sensor is located on front of engine, near crankshaftpulley. Disconnect CKP sensor connector. Using ohmmeter, measureresistance between terminals "A" and "B" at CKP sensor. See Fig. 11.Resistance should be as specified. SeeCRANKSHAFT POSITION SENSOR RESISTANCE table. 2) If resistance is not as specified, replace CKP sensor. OnMillenia 2.3L, when installing CKP sensor, adjust air gap to .040-.080" (1.0-2.0 mm). On all models except Millenia 2.3L and MPV, wheninstalling CKP sensor, adjust air gap to .020-.060" (.5-1.5 mm). MPVhas no air gap specification.

CRANKSHAFT POSITION SENSOR RESISTANCE

Application (1) Ohms

Protege ................................................... 500-600Miata ......................................................... (2)Millenia 2.3L ............................................ 950-1250Millenia 2.5L & 626 ....................................... 520-580MPV ....................................................... 315-385

(1) - With sensor temperature at 68

F (20

C).(2) - Information not available from manufacturer.

Fig. 11: Checking Crankshaft Position Sensor Resistance (Typical)Courtesy of Mazda Motors Corp.

EGR BOOST SENSOR


16/64

See EXHAUST GAS RECIRCULATION (EGR) SYSTEM under EMISSIONSYSTEMS & SUB-SYSTEMS.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

Except Miata & Protege Remove ECT sensor. Place ECT sensor and thermometer in acontainer of water. Connect ohmmeter between ECT sensor terminals.Slowly heat water. Observe resistance reading at specifiedtemperatures. SeeENGINE COOLANT TEMPERATURE (ECT) SENSOR SPECIFICATIONS table. Ifresistance is not as specified, replace ECT sensor.

Miata & Protege 1) Coolant temperature sender is part of ECT sensor. RemoveECT sensor. ECT sensor is located on left side of engine. Place ECTsensor and thermometer in a container of water. Connect ohmmeterbetween ECT sensor terminals "A" and "B". See Fig. 12.

2) Slowly heat water. Observe resistance reading at specifiedtemperatures. SeeENGINE COOLANT TEMPERATURE (ECT) SENSOR SPECIFICATIONS table. Ifresistance is not as specified, replace ECT sensor. 3) To check coolant temperature sender portion of ECT sensor,measure resistance between ground and ECT sensor terminal "C". SeeFig. 12. Resistance should be 152-242 ohms with sensor temperature at122

F (50

C). Replace ECT sensor as necessary.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR SPECIFICATIONS

Temperature

F (

C) Ohms

Miata, MPV & Protege 68 (20) ............................................... 2200-2800

176 (80) ................................................ 290-400Millenia 68 (20) ............................................... 2200-2700 176 (80) ................................................ 290-350626 68 (20) ........................................... 35,500-39,200 176 (80) .............................................. 7180-7920

Fig. 12: Identifying ECT Sensor Terminals (Miata & Protege)Courtesy of Mazda Motors Corp.

FUEL TANK PRESSURE SENSOR


17/64

1) Connect NGS scan tool to Data Link Connector (DLC). DLC islocated under left side of instrument panel, right of steering column.Turn ignition on. Using scan tool, access DIAGNOSTIC DATA LINK menu,and select PCM. Highlight and select PID/DATA MONITOR AND RECORD.Select FTP V PID. 2) With 2 psi (6.7 kPa) of pressure applied to sensor,voltage should be 4-5 volts. With 0 psi (0 kPa) of pressure applied tosensor, voltage should be 2.3-2.8 volts. With 2 in. Hg of vacuumapplied to sensor, voltage should be .45-.55 volt. If all voltagereadings are as specified, fuel tank pressure sensor is functioningproperly. If any voltage reading is not as specified, go to next step. 3) Turn ignition off. Check continuity of circuits betweenfuel tank pressure sensor wiring harness connector and PCM. Seeappropriate wiring diagram in WIRING DIAGRAMS article. If continuityexists in all circuits, go to next step. If continuity does not existin one or more circuits, repair wiring harness as necessary. 4) Turn ignition on. Measure voltage at terminal "B" at fuelpressure sensor wiring harness connector. See Fig. 13. Voltage should

be less than one volt. Measure voltage at terminal "C" at fuel tankpressure sensor wiring harness connector. Voltage should be 4.5-5.5volts. If voltage is as specified, replace fuel tank pressure sensor.If voltage is not as specified, locate and repair short circuit inwiring harness. See appropriate wiring diagram in WIRING DIAGRAMSarticle.

Fig. 13: Identifying Fuel Tank Pressure Sensor Wiring HarnessConnector Terminals (Millenia & Protege Shown; MAP Sensor On Millenia2.3L Is Similar)Courtesy of Mazda Motors Corp.


18/64

HEATED OXYGEN SENSOR (HO2S)

Miata 1) Warm engine to normal operating temperature. Connect NGSscan tool to Data Link Connector (DLC). DLC is located under left sideof instrument panel, right of steering column. Using scan tool, accessDIAGNOSTIC DATA LINK menu, and select PCM. Highlight and selectPID/DATA MONITOR AND RECORD. 2) Turn ignition on. Select FHO2S PID for front sensor orRHO2S PID for rear sensor. See HO2S VOLTAGE (MIATA) table. If voltageis not as specified, check wiring harness between PCM and HO2S. Alsocheck intake manifold system, fuel system and self-diagnostic system.Repair as necessary. If no problems are found, replace HO2S. 3) To test HO2S heating element, allow sensor to cool to roomtemperature. Disconnect HO2S connector. Using ohmmeter, measureresistance between sensor terminals "C" and "D". See Fig. 14.Resistance should be about 16 ohms with sensor temperature at 68

F(20

C). If resistance is not as specified, replace HO2S.

HO2S VOLTAGE (MIATA)

Application Volts

PCM Terminal 3V (Rear Sensor) Acceleration ............................................ 0.5-1.0 Deceleration .............................................. 0-0.5 Idle ...................................................... 0-1.0PCM Terminal 1U (Front Sensor) Acceleration ............................................ 0.5-1.0 Deceleration .............................................. 0-0.5 Idle ...................................................... 0-1.0

Fig. 14: Identifying HO2S Terminals (Miata & Protege 1.8L)Courtesy of Mazda Motors Corp.

Millenia 1) Warm engine to normal operating temperature. Connect scan


19/64

tool to Data Link Connector (DLC). DLC is located under left side ofinstrument panel, right of steering column. Using scan tool, accessDIAGNOSTIC DATA LINK menu, and select PCM. Highlight and selectPID/DATA MONITOR AND RECORD. 2) Turn ignition on. Select HO2S PID to be checked. SeeHO2S PID IDENTIFICATION (MILLENIA) table. Voltage should be .5-1.0volt under acceleration and 0-.5 volt under deceleration. If voltageis not as specified, check wiring harness and connector between PCMand HO2S. Also check intake manifold system, fuel system and self-diagnostic system. Repair as necessary. If no problems are found,replace HO2S. 3) To test HO2S heating element on 2.5L, go to next step. Totest HO2S heating element on 2.3L, allow sensor to cool to roomtemperature. Disconnect HO2S connector. Using ohmmeter, measureresistance between sensor terminals "B" and "C" for front sensor orterminals "C" and "D" for rear sensor. See Fig. 15. Resistance shouldbe about 6 ohms with sensor temperature at 68

F (20

C). If resistanceis not as specified, replace HO2S.

4) To test HO2S heating element on 2.5L, allow sensor to coolto room temperature. Disconnect HO2S connector. Using ohmmeter,measure resistance between sensor terminals "C" and "D". See Fig. 16.Resistance should be about 6 ohms with sensor temperature at 68

F(20

C). If resistance is not as specified, replace HO2S.

HO2S PID IDENTIFICATION (MILLENIA)

HO2S PID

2.3L Left Front Sensor ...................................... FHO2S L Left Rear Sensor ........................................ RHO2S L Right Front Sensor ...................................... RHO2S R Right Rear Sensor ...................................... FHO2S R

2.5L Left Front Sensor ...................................... FHO2S L Middle Sensor ............................................. MHO2S Rear Sensor ............................................... RHO2S Right Front Sensor ...................................... FHO2S R

Fig. 15: Identifying HO2S Terminals (Millenia 2.3L)Courtesy of Mazda Motors Corp.


20/64

Fig. 16: Identifying HO2S Terminals (Millenia 2.5L)Courtesy of Mazda Motors Corp.

MPV 1) Warm engine to normal operating temperature. Turn ignitionoff. Disconnect suspect HO2S connector. Connect voltmeter to sensorterminals. See HO2S TERMINAL IDENTIFICATION (MPV) table. Start engine.Raise engine speed to 3000 RPM until voltage varies between zero and

one volt. Allow engine to idle. Accelerate engine several times.Voltage should be .5-1.0 volt when accelerating, 0-.5 volt whendecelerating. If voltage is as specified, go to next step. If voltageis not as specified, replace sensor. 2) Check for open or short on wiring between suspect HO2S andPCM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repairas necessary. 3) To test HO2S heating element, allow sensor to cool to roomtemperature. Disconnect HO2S connector. Using ohmmeter, measureresistance between specified terminals. SeeHO2S HEATER TERMINAL & RESISTANCE IDENTIFICATION (MPV) table. Ifresistance is not as specified, replace HO2S.

HO2S TERMINAL IDENTIFICATION (MPV)

Application Terminals

Left Front ........................................... C (+), D (-)Left Rear ............................................ C (+), D (-)Right Front .......................................... A (+), B (-)Right Rear ........................................... A (+), B (-)Middle ............................................... C (+), D (-)Rear ................................................. C (+), D (-)

HO2S HEATER TERMINAL & RESISTANCE IDENTIFICATION (MPV)

Application Terminals Ohms

Left Front ..................... A & B .................. 5.0-6.8


21/64

Right Front .................... C & D .................. 5.0-6.8Middle (1) ..................... A & B ............... About 15.7Left Rear (2) .................. A & B ................ 14.2-18.8Right Rear (2) ................. C & D ................ 14.2-18.8Rear (1) ....................... A & B ............... About 15.7

(1) - Federal models only.(2) - California Models only.

Protege 1) Warm engine to normal operating temperature. Connect NGSscan tool to Data Link Connector (DLC). DLC is located under left sideof instrument panel, right of steering column. Using scan tool, accessDIAGNOSTIC DATA LINK menu, and select PCM. Highlight and selectPID/DATA MONITOR AND RECORD. 2) Turn ignition on. Select FHO2S PID for front sensor orRHO2S PID for rear sensor. See HO2S VOLTAGE (PROTEGE) table. If

voltage is not as specified, check wiring harness between PCM andHO2S. Also check intake manifold system, fuel system and self-diagnostic system. Repair as necessary. If no problems are found,replace HO2S. 3) To test HO2S heating element, allow sensor to cool to roomtemperature. Disconnect HO2S connector. On 1.6L, measure resistancebetween HO2S terminals "B" and "C" for front sensor or "C" and "D" forrear sensor. See Fig. 17. Resistance should be about 6 ohms at 68

F(20

C). If resistance is not as specified, replace HO2S. 4) On 1.8L, measure resistance between HO2S terminals "D" and"C". See Fig. 14. Resistance should be about 16 ohms. On all models,if resistance is not as specified, replace HO2S.

HO2S VOLTAGE (PROTEGE)

Application Volts

Acceleration .............................................. 0.5-1.0Deceleration ................................................ 0-0.5Idle ........................................................ 0-1.0

Fig. 17: Identifying HO2S Terminals (Protege 1.6L)Courtesy of Mazda Motors Corp.

626 2.0L (Using Breakout Box) 1) Warm engine to normal operating temperature. Turn ignition


22/64

off. Connect 104-Pin Breakout Box (49 UN01 130) to PCM. Measurevoltage at PCM terminal No. 60 for front sensor or No. 35 for rearsensor. See HO2S VOLTAGE (626 2.0L) table. 2) If voltage is not as specified, check wiring harness andconnector between PCM and HO2S. Also check intake manifold system,fuel system and self-diagnostic system. Repair as necessary. If noproblems are found, replace HO2S. 3) To test HO2S heating element, allow sensor to cool to roomtemperature. Disconnect HO2S connector. Using ohmmeter, measureresistance between terminals "C" and "D" for 4-terminal sensor or "B"and "C" for 3-terminal sensor. See Fig. 18. Resistance should be about6 ohms at 68

F (20

C). If resistance is not as specified, replaceHO2S.

HO2S VOLTAGE (626 2.0L)

Application Volts

PCM Terminal No. 35 (Rear Sensor) Acceleration .............................................. 0-1.0 Deceleration .............................................. 0-1.0 Idle ...................................................... 0-1.0PCM Terminal No. 60 (Front Sensor) Acceleration .............................................. 0-1.0 Deceleration .............................................. 0-0.5 Idle .................................................... 0.5-1.0

Fig. 18: Identifying HO2S Terminals (626 2.0L)Courtesy of Mazda Motors Corp.

626 2.0L (Using New Generation Star (NGS) Scan Tool) 1) Warm engine to normal operating temperature. Connect NGSscan tool to Data Link Connector (DLC). DLC is located under left sideof instrument panel, right of steering column. Using scan tool, accessDIAGNOSTIC DATA LINK menu, and select PCM. Highlight and selectPID/DATA MONITOR AND RECORD. 2) Turn ignition on. Select FHO2S PID for front sensor orRHO2S PID for rear sensor. See PIN VOLTAGE/PID VALUE CHARTS article.


23/64

If voltage is not as specified, check wiring harness between PCM andHO2S. Also check intake manifold system, fuel system and self-diagnostic system. Repair as necessary. If no problems are found,replace HO2S. 3) To test HO2S heating element, allow sensor to cool to roomtemperature. Disconnect HO2S connector. Using ohmmeter, measureresistance between terminals "B" and "C" for 3-terminal sensor or "C"and "D" for 4-terminal sensor. See Fig. 18. Resistance should be about6 ohms at 68

F (20

C). If resistance is not as specified, replaceHO2S.

626 (2.5L) 1) Warm engine to normal operating temperature. Connect NGSscan tool to Data Link Connector (DLC). DLC is located under left sideof instrument panel, right of steering column. Using scan tool, accessDIAGNOSTIC DATA LINK menu, and select PCM. Highlight and selectPID/DATA MONITOR AND RECORD. 2) Turn ignition on. Select HO2S Parameter Identification

(PID) to be checked and note voltage reading. SeeHO2S PID IDENTIFICATION (626 2.5L) table. See PIN VOLTAGE/PID VALUECHARTS article. If voltage is not as specified, check wiring harnessand connector between PCM and HO2S. Also check intake manifold system,fuel system and self-diagnostic system. Repair as necessary. If noproblems are found, replace HO2S. 3) To test HO2S heating element, allow sensor to cool to roomtemperature. Disconnect HO2S connector. Using ohmmeter, measureresistance between terminals "C" and "D" for rear sensor. See Fig. 19.Resistance should be about 6 ohms at 68

F (20

C). If resistance isnot as specified, replace HO2S.

HO2S PID IDENTIFICATION (626 2.5L)

HO2S PID

Left Front Sensor ........................................... O2S11Middle Sensor ............................................... O2S21Rear Sensor ................................................. O2S12Right Front ................................................. O2S13

Fig. 19: Identifying HO2S Terminals (626 2.5L)Courtesy of Mazda Motors Corp.

INTAKE AIR TEMPERATURE (IAT) SENSOR


24/64

Miata, Millenia 2.5L, Protege 1.6L & 626 Locate and remove IAT sensor from air cleaner housing. PlaceIAT sensor and thermometer in a container of water. Connect ohmmeterbetween IAT sensor terminals. Slowly heat water. Observe resistance atspecified temperatures. SeeINTAKE AIR TEMPERATURE SENSOR SPECIFICATIONS (MIATA, MILLENIA 2.5L,PROTEGE 1.6L & 626) table. If resistance is not as specified, replaceIAT sensor.

INTAKE AIR TEMPERATURE SENSOR SPECIFICATIONS (MIATA, MILLENIA 2.5L,PROTEGE 1.6L & 626)

Temperature

F (

C) Ohms

Millenia 2.5L 68 (20) ............................................... 2200-2700 176 (80) ................................................ 290-350Miata

68 (20) ............................................... 2090-2810 176 (80) ................................................ 274-370626 68 (20) ........................................... 35,500-39,200 140 (60) .............................................. 7180-7920Protege 1.6L 68 (20) ............................................... 2200-2700 176 (80) ................................................ 290-340

Millenia 2.3L 1) Vehicle is equipped with 3 different IAT sensors. Each IATsensor has unique resistance characteristics. One IAT sensor islocated in air filter housing, another sensor is located in dynamicchamber at right rear of engine, and remaining IAT sensor is located

in Lysholm compressor on top right of engine. 2) Remove IAT sensor(s) to be tested. Place IAT sensor andthermometer in a container of water. Connect ohmmeter between IATsensor terminals. Slowly heat water. Observe resistance reading atspecified temperatures. See IAT SENSOR RESISTANCE (MILLENIA 2.3L)table. If resistance is not as specified, replace IAT sensor.

IAT SENSOR RESISTANCE (MILLENIA 2.3L)

Temperature

F (

C) Ohms

IAT Sensor (Air Cleaner Housing) 68 (20) ............................................... 2200-2700 176 (80) ................................................ 290-350IAT Sensor (Dynamic Chamber) 77 (25) ........................................... 29,700-36,300 185 (85) .............................................. 3330-3670IAT Sensor (Lysholm Compressor) 212 (100) ............................................. 5600-6900

MPV IAT sensor is part of Mass Airflow (MAF) sensor. DisconnectMAF sensor connector. Using ohmmeter, measure resistance between MAFsensor terminals "A" and "F", located at each end of connector. SeeIAT RESISTANCE (MPV) table. If resistance is not as specified, replaceMAF sensor. Check for open or short on wiring between IAT sensor andPCM. Repair as necessary.

IAT RESISTANCE (MPV)


25/64

Temperature

F (

C) Ohms

50 (10) ................................................. 3300-410068 (20) ................................................. 2200-270086 (30) ................................................. 1400-1900

Protege 1.8L IAT sensor is part of Mass Airflow (MAF) sensor. DisconnectMAF sensor connector. Using ohmmeter, measure resistance between MAFsensor terminals "C" and "D". See Fig. 20. Resistance should be 2210-2690 ohms. If resistance is not as specified, replace MAF sensor.

Fig. 20: Identifying MAF Sensor Terminals (Protege 1.8L)Courtesy of Mazda Motors Corp.

KNOCK SENSOR

Miata, Millenia & 626 2.5L Disconnect knock sensor connector. Using ohmmeter, measureresistance between knock sensor terminal "A" (Red wire on Millenia 2.3L, White wire on all others) and knock sensor body. Resistance should

be about 560,000 ohms at 68

F (20

C). If resistance is not asspecified, replace knock sensor.

MPV Disconnect knock sensor connector. Using ohmmeter, measureresistance between knock sensor terminals "A" (Red wire) and "B"(Black wire). Resistance should be about 560,000 ohms at 68

F (20

C).If resistance is not as specified, replace knock sensor.

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

Millenia 2.3L 1) MAP sensor is located in right rear of engine compartment.Connect NGS scan tool to Data Link Connector (DLC). DLC is locatedunder left side of instrument panel, right of steering column. Turn


26/64

ignition on. Using scan tool, access DIAGNOSTIC DATA LINK menu, andselect PCM. Highlight and select PID/DATA MONITOR AND RECORD. SelectMAP V PID. 2) With 29.5 psi (100 kPa) of pressure applied to sensor,voltage should be 4-5 volts. With 0 psi (0 kPa) of pressure applied tosensor, voltage should be 2.3-2.8 volts. With 25.6 in. Hg of vacuumapplied to sensor, voltage should be .9-1.1 volts. If all voltagereadings are as specified, MAP sensor is functioning properly. If anyvoltage reading is not as specified, go to next step. 3) Turn ignition off. Check continuity of circuits betweenMAP sensor wiring harness connector and PCM. See appropriate wiringdiagram in WIRING DIAGRAMS article. If continuity exists in allcircuits, go to next step. If continuity does not exist in one or morecircuits, repair wiring harness as necessary. 4) Turn ignition on. Measure voltage at terminal "B" at MAPsensor wiring harness connector. See Fig. 13. Voltage should be 4.5-5.5 volts. Measure voltage at terminal "C" at fuel tank pressure sensorwiring harness connector. Voltage should be less than one volt. If

voltage is as specified, replace MAP sensor. If voltage is not asspecified, locate and repair short circuit in wiring harness. Seeappropriate wiring diagram in WIRING DIAGRAMS article.

MASS AIRFLOW (MAF) SENSOR

1) Visually check MAF sensor for cracks or damage. If anydamage is present, replace MAF sensor. If no damage is present, turnoff all accessories. Connect New Generation Star (NGS) scan tool toData Link Connector (DLC). DLC is located under left side ofinstrument panel, right of steering column. Turn ignition on. 2) Using scan tool, select PID/DATA MONITOR AND RECORDfunction. Select MAF V PID and record value while operating vehicleunder specified conditions. See MASS AIRFLOW (MAF) SENSOR VOLTAGEtable. If voltage is not as specified, check continuity of each

circuit between MAF sensor and PCM. See appropriate wiring diagram inWIRING DIAGRAMS article. Repair as necessary. If continuity exists inall circuits, replace MAF sensor.

MASS AIRFLOW (MAF) SENSOR VOLTAGE

Condition Volts

Miata Ignition On ............................................. 0.9-2.0 Idle .................................................... 1.7-2.4Millenia Ignition On ............................................. 1.0-1.5 Idle .................................................... 1.5-2.5MPV

Ignition On ................................................ 0-.1 Idle ...................................................... .5-.8Protege 1.6L Ignition On ........................................... 0.6-1.5 Idle .................................................. 0.8-2.2 1.8L Ignition On ........................................... 0.2-1.0 Idle .................................................. 0.2-2.0626 2.0L Ignition On ............................................... 0.2 Idle .................................................. 0.6-1.1 2.5L Ignition On ..................................... Less Than 1.0


27/64

Idle .................................................. 1.0-2.0

NEUTRAL SWITCH (M/T)

Protege & 626 Disconnect neutral switch. Using ohmmeter, check continuitybetween switch terminals. Ensure continuity exists with transmissionin Neutral and does not exist in any other gear. Replace switch asnecessary.

POWER STEERING PRESSURE (PSP) SWITCH

Millenia, MPV, Protege & 626 Disconnect power steering pressure switch connector. Connectohmmeter between PSP switch and ground. Start engine and operate atidle. Turn steering wheel from side to side and observe ohmmeter.Continuity should exist when steering wheel is turned. Continuityshould not exist when steering wheel is straight ahead. If continuityis not as specified, replace PSP switch.

THROTTLE POSITION SENSOR

See ON-VEHICLE ADJUSTMENTS article for TP sensor testing andadjustment procedures.

TRANSMISSION RANGE SENSOR (626 2.0L A/T)

See TRANSMISSION SERVICE & REPAIR for testing and adjustmentprocedures.

TRANSMISSION RANGE SWITCH (EXCEPT 626 2.0L A/T)

Miata, Millenia, MPV, Protege & 626 2.5L 1) Check for starter operation with ignition switch in STARTposition and shift lever in "P" and "N" position only. Ensure back-uplights illuminate with ignition in ON position and selector lever in"R". 2) To test switch, disconnect transmission range switchconnector. Check for continuity between specified terminals attransmission range switch. See Figs. 21, 22, 23 or 24. If continuityis not as specified, replace switch.

Fig. 21: Checking Transmission Range Switch (Miata)Courtesy of Mazda Motors Corp.


28/64

Fig. 22: Checking Transmission Range Switch (Millenia 2.3L)Courtesy of Mazda Motors Corp.

Fig. 23: Checking Transmission Range Switch (Millenia 2.5L,Protege & 626 2.5L)Courtesy of Mazda Motors Corp.


29/64

Fig. 24: Checking Transmission Range Switch (MPV)Courtesy of Mazda Motors Corp.

VEHICLE SPEED SENSOR (VSS)


30/64

Miata, Millenia, Protege & 626 VSS is located on side of transaxle (transmission on Miata).Disconnect negative battery cable. Disconnect VSS connector. Rotatefront wheels (rear wheels on Miata) and measure voltage between sensorterminals. See Fig. 25. If voltmeter needle does not fluctuate,replace sensor.

Fig. 25: Checking Speedometer SensorCourtesy of Mazda Motors Corp.

MPV VSS is located on side of transaxle. Disconnect VSS

connector. Remove VSS. Rotate gear and measure voltage between sensorterminals. See Fig. 25. If voltmeter needle does not fluctuate,replace sensor.

RELAYS & SOLENOIDS

FUEL PUMP RELAY

Miata

NOTE: The fuel pump relay mounting lock is easily broken when relay is removed. Test relay in place and remove relay only for replacement.


31/64

Disconnect negative battery cable. Disconnect fuel pump relayconnector, located above accelerator pedal. Check continuity betweenrelay terminals "A" and "B". See Fig. 26. Continuity should exist.Using jumper wires, connect positive battery terminal to relayterminal "A". Connect relay terminal "B" to battery negative terminal.Continuity should exist between relay terminals "C" and "D". Replacerelay if continuity is not as specified.

Fig. 26: Identifying Fuel Pump Relay Terminals (Miata)Courtesy of Mazda Motors Corp.

Millenia, Protege & 626 Remove fuel pump relay. See FUEL PUMP RELAY LOCATIONS table.Using ohmmeter, check for continuity between relay terminals "C" and"D". See Fig. 27. Continuity should not exist. Apply battery voltageto terminal "A" and ground terminal "B". Again, check for continuitybetween relay terminals "C" and "D". Continuity should exist with

battery voltage applied. If continuity is not as specified, replacefuel pump relay.

FUEL PUMP RELAY LOCATIONS


Millenia 2.3L ......... In Left Rear Of Engine Compartment, Mounted Near Cruise ActuatorMillenia 2.5L &626 ......................... Fuse/Relay Box In Left Side Of Engine CompartmentProtege ................ Mounted On Passenger Side Of Front Console


32/64

Fig. 27: Testing Main & Fuel Pump RelaysCourtesy of Mazda Motors Corp.

MPV Remove fuel pump relay, located in main fuse and relay box,next to battery. Using ohmmeter, check for continuity between relayterminals "C" and "E". See Fig. 28. Continuity should not exist. Applybattery voltage to terminal "A" and ground terminal "B". Again, checkfor continuity between relay terminals "C" and "E". Continuity shouldexist with battery voltage applied. If continuity is not as specified,replace fuel pump relay.

Fig. 28: Testing Fuel Pump Relay (MPV)Courtesy of Mazda Motors Corp.

FUEL PUMP RESISTOR & RELAY (SPEED)


33/64

Millenia 2.3L 1) Fuel pump resistor and relay (speed) is located in leftrear corner of engine compartment. Disconnect fuel pump resistor andrelay connector. To check fuel pump resistor, measure resistancebetween relay terminals "A" and "B". See Fig. 29. Resistance should be.38-.42 ohm. If resistance is not as specified, replace fuel pumpresistor and relay. 2) To check relay, check for continuity between terminals "E"and "F". See Fig. 29. Continuity should not exist. Using jumper wires,apply battery voltage to connector terminals "C" and "D". Continuityshould exist between terminals "E" and "F". If continuity is not asspecified, replace fuel pump resistor and relay (speed).

Fig. 29: Identifying Fuel Pump Resistor & Relay (Speed) ConnectorTerminals (Millenia 2.3L)Courtesy of Mazda Motors Corp.

MAIN RELAY


34/64

1) Ensure main relay clicks when ignition is turned on andoff. If no sound is heard, locate and remove main relay from main fuseblock, in left side of engine compartment. Using ohmmeter, checkcontinuity between terminals "C" and "D". See Fig. 27. Continuityshould not exist. 2) Using jumper wires, apply battery voltage to relayterminal "A" and ground terminal "B". Check continuity between relayterminals "C" and "D". Continuity should exist with battery voltageapplied. If continuity is not as specified, replace main relay.

SOLENOIDS

Air By-Pass Valve (ABV) Vent Solenoid Valve (Millenia 2.3L) See AIR CHARGING PRESSURE CONTROL (MILLENIA 2.3L) under AIRINDUCTION SYSTEMS.

By-Pass Air Solenoid Valve (Millenia 2.3L)

1) Solenoid valve is located in right rear of enginecompartment. To identify solenoid valve, see appropriate illustrationin VACUUM DIAGRAMS article. Disconnect vacuum hoses and connector fromsolenoid valve. 2) Apply air pressure to a solenoid valve port. Air shouldnot flow from other port on valve. Using jumper wires, apply batteryvoltage to solenoid valve terminals. Air should flow through valve.Replace solenoid valve as necessary.

Charge Air Cooler By-Pass Solenoid Valve (Millenia 2.3L) See AIR CHARGING PRESSURE CONTROL (MILLENIA 2.3L) under AIRINDUCTION SYSTEMS.

EGR Vent Solenoid Valve See EXHAUST GAS RECIRCULATION (EGR) SYSTEM under EMISSION

SYSTEMS & SUB-SYSTEMS.

EGR Vacuum Solenoid Valve See EXHAUST GAS RECIRCULATION (EGR) SYSTEM under EMISSIONSYSTEMS & SUB-SYSTEMS.

Manifold Absolute Pressure (MAP) Sensor Solenoid Valve (Millenia 2.3L) Remove MAP sensor solenoid valve. Solenoid valve is mountedon top of right shock tower. Apply air pressure to port "B" ofsolenoid valve. See Fig. 3. Air from port "B" should flow from "C"only. Using jumper wires, apply battery voltage to solenoid valveterminals. Apply air pressure to port "A" of solenoid valve. Airshould flow from port "B" only. Replace solenoid valve as necessary.

Pressure Regulator Control (PRC) Solenoid Valve Disconnect vacuum hose from PRC solenoid valve. SeePRC SOLENOID VALVE LOCATIONS table. Apply air pressure to solenoidport "A". See Fig. 30. Air should flow from port "B". Using jumperwires, apply battery voltage to solenoid terminals. Apply air pressureto solenoid port "A". Air should flow through valve air filter.Replace solenoid valve as necessary.

PRC SOLENOID VALVE LOCATIONS


Millenia 2.3L ................................... Top Right Side Of Engine 2.5L ........................... Left Front Of Engine Compartment


35/64

626 2.0L ...................................... On Top Of Air Cleaner 2.5L ................................. On Side Of Intake ManifoldProtege ................... Right Rear Corner Of Engine Compartment

Fig. 30: Identifying PRC Solenoid Valve (Millenia, Protege & 626)Courtesy of Mazda Motors Corp.

Purge Control Solenoid See FUEL EVAPORATION (EXCEPT MPV) under EMISSION SYSTEMS &SUB-SYSTEMS.

VICS Solenoid See appropriate VARIABLE INERTIA CHARGING SYSTEM (VICS) underAIR INDUCTION SYSTEMS.

VRIS Solenoid SeeVARIABLE RESONANCE INDUCTION SYSTEM (VRIS) - MILLENIA 2.5L & 626 2.5Lunder AIR INDUCTION SYSTEMS.

FUEL SYSTEM

FUEL PRESSURE RELEASE

On all models except Protege, disconnect fuel pump relay. SeeFUEL PUMP RELAY LOCATIONS table. On Protege, disconnect fuel pumpconnector located behind rear seat. On all models, start engine (ifpossible) and allow to die. Turn ignition off. Reconnect fuel pumprelay or fuel pump connector (Protege).


36/64

FUEL PUMP RELAY LOCATIONS


Miata ..................................... Above Accelerator PedalMillenia2.3L ............. In Left Rear Of Engine Compartment, Mounted Near Cruise ActuatorMillenia2.5L ............ Fuse/Relay Box In Left Side Of Engine CompartmentMPV ............. Fuse/Relay Box In Left Side Of Engine CompartmentProtege ................ Mounted On Passenger Side Of Front Console626 ............. Fuse/Relay Box In Left Side Of Engine Compartment

FUEL DELIVERY

NOTE: For fuel system pressure testing, see BASIC DIAGNOSTIC PROCEDURES article.

Fuel Pump Circuit See FUEL PRESSURE under FUEL SYSTEM in BASIC DIAGNOSTICPROCEDURES article.

Fuel Pressure Regulator See FUEL PRESSURE under FUEL SYSTEM in BASIC DIAGNOSTICPROCEDURES article.

Pressure Regulator Control Solenoid See Pressure Regulator Control (PRC) Solenoid Valve underSOLENOIDS.

FUEL CONTROL

Fuel Injectors Using stethoscope, listen for normal clicking sound at eachinjector during idle and acceleration. If clicking sound is not heard,check injector wiring circuit, or main relay and circuit.

Fuel Injector Leakage 1) Using mechanics wire, secure each fuel injector to fuelrail. Disconnect fuel injector connectors. Remove fuel rail assemblyfrom intake manifold. See REMOVAL, OVERHAUL & INSTALLATION article.Reconnect fuel lines to fuel rail. Locate underhood Data LinkConnector (DLC) in left side of engine compartment. 2) Connect a jumper wire between underhood DLC terminals F/Pand GND. See Fig. 31. Turn ignition on. Tilt injectors about 60

degrees and check injector nozzles for fuel leaks. Fuel leakage shouldbe less than one drop every 2 minutes. If fuel leakage exists, replaceinjector.


37/64

Fig. 31: Identifying Data Link Connector TerminalsCourtesy of Mazda Motors Corp.

Fuel Injector Resistance (Except Millenia) Disconnect fuel injector connector. Using ohmmeter, measureresistance between injector terminals. Resistance should be about 13.8ohms (Protege 1.6L) or 12-16 ohms (all others). Replace injector asnecessary.

Fuel Injector Resistance (Millenia) Disconnect fuel injector connectors. Using ohmmeter, measureresistance between injector terminals. SeeCHECKING FUEL INJECTOR RESISTANCE (MILLENIA) table. See Fig. 32. Withsensor temperature at 68

F (20

C), resistance should be about 13.8ohms. Replace injectors as necessary.

CHECKING FUEL INJECTOR RESISTANCE (MILLENIA)


38/64

Application Check Between Terminals

Fuel Injector Left Bank 2 ....................................................... C & D 4 ....................................................... B & D 6 ....................................................... A & D Right Bank 1 ....................................................... A & B 3 ....................................................... A & D 5 ....................................................... A & C

Fig. 32: Identifying Fuel Injector Wiring Harness ConnectorTerminals (Millenia)Courtesy of Mazda Motors Corp.

Fuel Injector Volume (Miata) 1) Disconnect battery. Remove fuel rail assembly andinjectors from intake manifold. See REMOVAL, OVERHAUL & INSTALLATIONarticle. 2) Using mechanics wire, secure each fuel injector to fuelrail. Disconnect fuel injector connectors. Reconnect fuel lines tofuel rail.

3) Using Service tool (49L018901), connect battery to eachinjector in turn. Using a jumper wire, connect data link connectorterminals F/P and GND. Turn ignition on for 15 seconds. Measure fuelinjector volume. 4) If injector output volume is less than 66-82 ccs, replacesuspect injector, then check next injector. If injector output volumeis 66-82 ccs or more, check next injector. 5) When all injectors have been checked, reinstall allcomponents. recheck system.

Fuel Injector Volume (MPV) Disconnect battery. Remove fuel rail assembly and injectorsfrom intake manifold. See REMOVAL, OVERHAUL & INSTALLATION article.Using a fuel injector tester, check each injector output for 15seconds. If injector output volume is not 44-58 ccs, replace suspect


39/64

injector.

Fuel Cut Control System (Millenia) 1) To check system operation, connect New Generation Star (49T088 0A0) scan tool to Data Link Connector (DLC) No. 2. DLC 2 islocated under left side of instrument panel, right of steering column.Ensure engine is at normal operating temperature. Allow engine toidle. Turn A/C switch off. 2) Using scan tool, access DIAGNOSTIC DATA LINK menu, andselect PCM. Highlight and select PID/DATA MONITOR AND RECORD. SelectINJR and INJL. Scan tool will measure and display fuel injector pulsewidth. Increase engine speed to 4000 RPM, then quickly close throttlevalve. 3) Fuel injection pulse width should be zero millisecondsuntil engine speeds drops to about 1200 RPM, then pulse width shouldreturn to specification noted prior to increasing engine speed. Ifpulse width is as specified, A/C cutoff system is functioningproperly.

4) If pulse width is not as specified, measure voltage at PCMterminals 3Q (ECT sensor circuit), 3X (closed throttle position switchcircuit), 4AH and 4AL (crankshaft position sensor circuit). See PINVOLTAGE/PID VALUE CHARTS article. Repair as necessary.

IDLE CONTROL SYSTEM

SYSTEM CHECK (MPV)

1) Ensure engine is at ambient temperature. Connect scantool. Using PID/DATA monitor and record function, select ECT, IAC Vand RPM PIDs. Start engine. 2) Engine speed should decrease as engine reaches operatingtemperature. If idle speed decreases, go to next step. If engine speed

does not decrease, check ECT sensor, IAC valve and wiring. 3) Allow engine to warm to operating temperature. Check forDTC P0506, P0507 and P1504. If no DTCs are present, go to next step.If any DTCs are present, diagnose and repair as necessary. 4) Using scan tool, select SIMULATION TEST. Change duty cycleof IAC valve to 100 percent. If idle speed increases, go to next step.If idle speed does not increase, check IAC valve passages and wiring. 5) Using scan tool PID/DATA monitor and record function,select A/C SW, ALTF, IAC V, PSP SW, RPM and RPM DES PIDs. Ensure idlespeed stays in specification when accessories are operated. SeeIDLE SPECIFICATIONS table. If idle speed is okay, check is complete.If idle speed is not okay, check suspect component and circuit.

IDLE SPECIFICATIONS

Condition (1) Idle Speed

No Load ................................................... 700-800All Accessories On (2) .................................... 700-800Power Steering Operating .................................. 700-800A/C On .................................................... 800-900

(1) - In Neutral or Park.(2) - Headlights, fan switch, defroster and cooling fan are on.

BY-PASS AIR CONTROL (BAC) VALVE (MILLENIA)

1) On Millenia 2.3L, BAC valve is located on rear of frontcylinder head. See Fig. 33. On Millenia 2.5L, BAC valve is located


40/64

underneath throttle body. See Fig. 34. 2) On all models, ensure engine is cold. Start engine and letit idle. Idle speed should gradually decrease as engine reaches normaloperating temperature. If idle speed does not decrease, check coolanthose to BAC valve. Repair as necessary. If coolant hose is okay,replace BAC valve.

Fig. 33: Identifying BAC Valve (Millenia 2.3L)Courtesy of Mazda Motors Corp.

Fig. 34: Identifying BAC Valve (Millenia 2.5L)Courtesy of Mazda Motors Corp.

IDLE AIR CONTROL (IAC) VALVE


41/64

Miata, MPV, Protege & 626 Disconnect IAC valve connector. Using an ohmmeter, measureresistance between IAC valve terminals. SeeIAC VALVE RESISTANCE SPECIFICATIONS table. If resistance is not withinspecification, replace IAC valve.

Millenia IAC valve is part of By-Pass Control (BAC) valve. DisconnectIAC valve connector. Using an ohmmeter, measure resistance between IACvalve terminals. See IAC VALVE RESISTANCE SPECIFICATIONS table. Ifresistance is not as specified, replace BAC valve.

IAC VALVE RESISTANCE SPECIFICATIONS

Application Ohms

Miata, MPV & 626 2.5L ................................ (1) 8.7-10.5Millenia & Protege 1.8L .............................. (2) 0.7-12.3

Protege 1.6L & 626 2.0L ............................... (1) 7.7-9.3

(1) - With IAC valve temperature at 73

F (23)

C.(2) - With IAC valve temperature at 60

F (20)

C.

IGNITION SYSTEM

NOTE: For basic ignition checks, see BASIC DIAGNOSTIC PROCEDURES article.

EMISSION SYSTEMS & SUB-SYSTEMS

THREE-WAY CATAYLTIC CONVERTER (MPV)NOTE: If any HO2S DTC has been set, this test cannot be used.

1) Connect scan tool. On California models, monitor left WU-TWC using FHO2SL PID for upstream reading and RHO2SL for downstreamreading. Monitor right WU-TWC using FHO2SR PID for upstream readingand RHO2SR for downstream reading. On Federal models, monitor TWCusing FHO2S PID for upstream reading and RHO2S for downstream reading.On all models, press START to begin monitoring appropriate PIDS. 2) Drive vehicle at 40-60 MPH for 10 minutes to warm TWC tooperating temperature. Stop vehicle and allow to idle. Press TRIGGERto begin recording PIDs. Wait one minute, then press TRIGGER to endrecording PIDs. 3) Select appropriate PIDs and read graph in VIEW RECORDING.Count the number of times (inversions) the upstream reading crosses

the .5 volt line. Count the number of times (inversions) thedownstream reading crosses the .5 volt line. Do not count the numberof peaks. See Fig. 35. 4) Compare the inversions of the upstream reading to thedownstream reading. If the upstream reading has at least twice as manyinversions as the downstream reading or downstream reading has noinversions, TWC is okay.


42/64

Fig. 35: Identifying Upstream & Downstream HO2S InversionsCourtesy of Mazda Motors Corp.

EXHAUST GAS RECIRCULATION (EGR) SYSTEM


43/64

System Check (Except Miata, MPV & Protege) Check all connectors and vacuum hose routing. Check forcracks, leakage and restrictions, and repair as necessary. Startengine and operate throttle. Diaphragm of EGR control valve should notmove while engine is cold. Warm engine to operating temperature.Increase engine speed to about 2000 RPM, EGR control valve diaphragmshould move. If no movement is detected, check EGR system components.

System Check (Miata & MPV) 1) While listening to EGR valve, turn ignition on. If initialoperation of EGR valve is present, go to next step. If initialoperation of EGR valve is not present, check for DTCs. See appropriateSELF-DIAGNOSTICS article. Check EGR valve. See EGR Valve (Miata, MPV,Protege & 626). 2) Start engine. Connect scan tool and select SIMULATIONTEST. Using scan tool, increase EGR step value from 0 to 40. If idlespeed does not change, go to next step. If engine stumbles or stalls,go to step 5).

3) Turn ignition off. Remove EGR valve. Reconnect EGRelectrical connector. Turn ignition on. Using scan tool, increase EGRstep value from 0 to 40. If EGR valve operates, clean EGR valve andpassages. Install and retest. If EGR valve does not operate, replaceEGR valve and retest. 4) Warm engine to operating temperature. Raise and supportvehicle with drive wheels off the ground, or place vehicle on achassis dynamometer. Using scan tool, select PID/DATA MONITORfunction. Select SEGRP, RPM, VS, TP V, and ECT V PIDs. Start engineand allow vehicle to idle in gear. Ensure SEGRP PID is 0. Raise enginespeed and check SEGRP. If SEGRP does not change, go to next step. IfSEGRP changes, go to step 4). 5) Check TP PID for change when throttle is depressed. CheckVS PID for change when vehicle speed is increased. Check ECT PID forproper voltage when engine is at operating temperature. If any

problems exist, repair component or wiring as necessary and retest. 6) Stop vehicle. Check SEGRP PID at idle. Ensure SEGRP PID is0.

EGR Boost Sensor 1) Connect NGS scan tool to Data Link Connector (DLC). DLC islocated under left side of instrument panel, right of steering column.Turn ignition on. Using scan tool, access DIAGNOSTIC DATA LINK menu,and select PCM. Highlight and select PID/DATA MONITOR AND RECORD.Select BARO V PID. 2) Apply vacuum to sensor and monitor voltage. SeeEGR BOOST SENSOR SPECIFICATIONS table. If vacuum is exceeded, sensorwill be damaged. If all voltage readings are as specified, EGR boostsensor is functioning properly. If any voltage reading is not asspecified, go to next step. 3) Turn ignition off. Check continuity of circuits betweenEGR boost sensor wiring harness connector and PCM. See appropriatewiring diagram in WIRING DIAGRAMS article. If continuity exists in allcircuits, go to next step. If continuity does not exist in one or morecircuits, repair wiring harness as necessary. 4) Turn ignition on. Measure voltage at terminal "B" at fuelpressure sensor wiring harness connector. See Fig. 36. Voltage shouldbe less than one volt. Measure voltage at terminal "C" at fuel tankpressure sensor wiring harness connector. Voltage should be 4.5-5.5volts. If voltage is as specified, replace fuel tank pressure sensor.If voltage is not as specified, locate and repair short circuit inwiring harness. See appropriate wiring diagram in WIRING DIAGRAMSarticle.


44/64

Fig. 36: Identifying Boost Sensor TerminalsCourtesy of Mazda Motors Corp.

EGR BOOST SENSOR SPECIFICATIONS


45/64

Vacuum Applied (In. Hg) Volts

Millenia 2.5L & 626 0.0 ..................................................... 3.6-4.4 16.1 .................................................. 1.66-2.03 24.0 ................................................ 0.711-0.867MPV 7.9 ...................................................... .8-1.3Protege 0.0 ..................................................... 2.5-4.9 17.9 .................................................... 1.0-1.3

EGR Boost Solenoid (Millenia 2.5L, MPV, Protege & 626) Remove EGR boost solenoid. See EGR BOOST SOLENOID LOCATIONStable. Apply air pressure to port "B" of solenoid valve. See Fig. 3.Air should flow from port "C" only. Using jumper wires, apply batteryvoltage to solenoid valve terminals. Apply air pressure to port "A" of

solenoid valve. Air should flow from port "B" only. Replace solenoidvalve as necessary.

EGR BOOST SOLENOID LOCATIONS


Millenia 2.5L ................... Center Rear Of Engine CompartmentMPV ........................................... Next To Air CleanerProtege .......................... Right Rear Of Engine Compartment626 2.0L ....................................... Right Side Of Engine 2.5L ......................................... Top Rear Of Engine

EGR Position Sensor (Millenia) EGR position sensor is part of EGR valve. Disconnect EGRposition sensor connector. Disconnect vacuum hose from EGR controlvalve. Measure resistance between EGR position sensor terminals. SeeEGR POSITION SENSOR RESISTANCE table. See Fig. 37. Apply 5.9 in. Hg ofvacuum to EGR position sensor and recheck resistance. If resistance isnot as specified, replace EGR valve.

EGR POSITION SENSOR RESISTANCE

Terminals (1) Ohms With No (1) Ohms With Vacuum Applied Vacuum Applied

A & B ................ 2700 ................................ 2700A & C ................ 500 ................................. 2700B & C ................ 2400 ................................. 100

(1) - Specification listed is approximate.


46/64

Fig. 37: Testing EGR Position Sensor (Typical)Courtesy of Mazda Motors Corp.

EGR Vacuum Solenoid Valve (Millenia) Remove EGR vacuum solenoid. SeeEGR VACUUM/VENT SOLENOID VALVE LOCATIONS table. Apply air pressure toa solenoid valve port. See Fig. 39. Air should not flow from othersolenoid port. Using jumper wire, apply battery voltage to solenoidvalve terminals. Air should flow with voltage applied. If solenoidvalve does not operate as specified, replace valve.

EGR Valve (Miata, MPV, Protege & 626) 1) Using a stethoscope, listen for EGR valve initializationnoise (clicks) when starting and stopping engine. If clicking noise isheard, EGR valve is functioning properly. If clicking noise is notheard, go to next step. 2) Turn ignition off. Disconnect EGR valve connector. Usingan ohmmeter, measure resistance between EGR valve terminals "C" and"E", "C" and "A", "D" and "B" and between "D" and "F". See Fig. 38.Each resistance reading should be about 22 ohms. 3) If resistance is as specified, check wiring harnessbetween EGR valve and PCM. See appropriate wiring diagram in WIRINGDIAGRAMS article. If resistance is not as specified, replace EGRvalve.


47/64

Fig. 38: Identifying EGR Valve Terminals (Miata & Protege)Courtesy of Mazda Motors Corp.

EGR Valve (Millenia) Warm engine to normal operating temperature and operate at


48/64

idle. Disconnect and plug vacuum hose at EGR valve. Engine should runsmoothly. Connect vacuum pump to EGR valve, and apply vacuum. Engineshould run rough or stall. If engine does not operate as specified,replace EGR valve.

EGR Vent Solenoid Valve (Millenia) Remove EGR vent solenoid valve. SeeEGR VACUUM/VENT SOLENOID VALVE LOCATIONS table. Apply air pressure toport "A". See Fig. 39. Air should flow from ports "B" and "C". Usingjumper wires, apply battery voltage to solenoid valve terminals. Applyair pressure to port "A". Air should flow from port "B" only. Replacesolenoid valve as necessary.

EGR VACUUM/VENT SOLENOID VALVE LOCATIONS


Millenia ......................... Right Rear Of Engine Compartment

626 2.0L ....................................... Right Side Of Engine 2.5L .......................... Center Rear Of Engine Compartment

Fig. 39: Testing EGR Vacuum & Vent Solenoid Valves (Millenia)Courtesy of Mazda Motors Corp.

FUEL EVAPORATION (EXCEPT MPV)

NOTE: For system testing, see appropriate SELF-DIAGNOSTICS article.

System Inspection Purge system operation takes place when vehicle isaccelerating in gear (off idle), engine is at operating temperatureand oxygen sensor is functioning normally. Ensure all vapor lines areconnected and in acceptable condition. See Figs. 40, 41 or 42.

NOTE: Evaporative emission system schematic for 626 is not available from manufacturer.


49/64

Fig. 40: Identifying Evaporative Emission Components (Miata)Courtesy of Mazda Motors Corp.


50/64

Fig. 41: Identifying Evaporative Emission Components (Millenia)Courtesy of Mazda Motors Corp.


51/64

Fig. 42: Identifying Evaporative Emission Components (Protege)Courtesy of Mazda Motors Corp.

Charcoal Canister (Miata) Remove charcoal canister. Plug two smaller ports. Blow air


52/64

into large port. If canister leaks, replace canister.

Charcoal Canister (Millenia & Protege) Charcoal canister is located under rear of vehicle. PlugCanister Drain Cut Valve (CDCV) port and purge solenoid valve port.See Figs. 43 or 44. Apply small amount of air pressure to fuel tankport on charcoal canister. If air leaks, replace charcoal canister.

Fig. 43: Identifying Charcoal Canister Ports (Millenia)Courtesy of Mazda Motors Corp.

Fig. 44: Identifying Charcoal Canister Ports (Protege)Courtesy of Mazda Motors Corp.

Charcoal Canister (626) Check for loose, missing, cracked and broken connections andparts. Repair or replace as necessary. No liquid should exist in


53/64


54/64

Remove catch tank, located in right front of enginecompartment. Blow air into tank and check for leaks. Replace if anyleaks are present.

One-Way Check Valve (Millenia) One-way check valve is located on top of fuel tank. Notedirection of valve installation. Remove check valve. Apply airpressure to check valve port "A". See Fig. 46. Air should flow fromport "B". Apply air pressure to port "B". Air should not flow fromport "A". If check valve does not operate as specified, replace checkvalve.

Fig. 46: Identifying One-Way Check Valve (Millenia)Courtesy of Mazda Motors Corp.

2-Way Check Valve (Protege) Remove check valve, located at rear of vehicle by fuelfiller. Apply air pressure to port "B". See Fig. 47. Air should flowfrom port "C". Apply air pressure to port "C". Air should flow fromport "A". Replace 2-way check valve as necessary.

Fig. 47: Identifying 2-Way Check Valve (Protege)Courtesy of Mazda Motors Corp.

Fuel Vapor Rollover Valve (Miata) Vehicle is equipped with 1 fuel vapor valve located in top offuel tank. Remove rear package tray trim, service cover, evap hose andvalve. With valve in upright position, air should flow through valve.With valve turned upside down, air should not flow through valve. Ifvalve does not operate as specified, replace fuel vapor rollovervalve.


55/64

Fuel Vapor Rollover Valve (Millenia) Vehicle is equipped with 2 fuel vapor valves, built into topof fuel tank. With valve in upright position, air should flow throughvalve. With valve turned upside down, air should not flow throughvalve. If fuel vapor valve does not operate as specified, replace fueltank.

Fuel Vapor Rollover Valve (Protege & 626) Two fuel vapor rollover valves are located in top of fueltank. Remove fuel vapor valve. It may be necessary to remove fuel tankto access valve. Hold valve in level upright position. Blow air intoport (hose barb). Air should flow through valve to lower port. Turnvalve upside down. Air should not flow through valve. Replace valve asnecessary.

Purge Control Solenoid Valve Disconnect purge control solenoid valve connector. See

PURGE CONTROL SOLENOID VALVE LOCATIONS table. Ensure air does not flowthrough solenoid valve vacuum ports. Using jumper wires, apply batteryvoltage to solenoid valve terminals. Apply air pressure to a solenoidvalve port. Air should flow from other port. If valve does not operateas specified, replace solenoid valve.

PURGE CONTROL SOLENOID VALVE LOCATIONS


Miata ........................... Right Front Of Engine CompartmentMillenia 2.3L ........................................ Top Right Of Engine 2.5L .......................... Center Rear Of Engine Compartment626

2.0L .................................... On Right Side Of Plenum 2.5L ............................... Between Air Filter & BatteryProtege ......................... Center Rear Of Engine Compartment

Tank Pressure Control Valve (Miata) 1) Remove Tank Pressure Control Valve (TPCV), located abovefuel tank. 2) Apply air pressure to inlet port (on same side aselectrical connector). At pressures less than .03 psi (.20 kPa), airshould not flow. At pressures more than .14 psi (.98 kPa), air shouldflow through valve. 3) Using a vacuum pump, apply vacuum to inlet port. Withvacuum at more than .3 in. Hg (-.98 kPa), air should flow throughvalve. Replace TPCV as necessary.

Tank Pressure Control Valve (Protege) 1) Remove Tank Pressure Control Valve (TPCV), located on topof fuel tank. 2) Apply air pressure to inlet port (on same side aselectrical connector). At pressures less than .03 psi (.20 kPa), airshould not flow. At pressures more than .14 psi (.98 kPa), air shouldflow through valve. 3) Using a vacuum pump, apply vacuum to inlet port. Withvacuum at more than .3 in. Hg, air should flow through valve. ReplaceTPCV as necessary.


56/64

Purge system operation takes place when vehicle isaccelerating in gear (off idle), engine is at operating temperatureand oxygen sensor is functioning normally. Ensure all vapor lines areconnected and in acceptable condition. See Fig. 48.

Fig. 48: Identifying Evaporative Emission Components (MPV)Courtesy of Mazda Motors Corp.

EVAP System Test

NOTE: This can be used as an alternative to Drive mode 4.

1) Connect scan tool. Select startup. Select metric. CheckPIDs. Ensure BARO (72.2 kPa or more), ECT (-7.5-70

C), FLT V (1.1-3.0

volts) and IAT (0-60

C) are as specified. Ensure IAT and ECT arewithin 10

C. 2) Start engine. Run engine at 3500 RPM for 3.5 minutes.Select DIAGNOSTIC SUPPORT PROCEDURE, SINGLE TEST, EVAP LEAK TEST.Press trigger. Engine spped should raise to 2000 RPM. After oneminute, depress accelerator to end test. Check and record FTP1SV andFTP2SV PIDs. Check FTP1SV PID value. See Fig. 49. If PID is okay, goto next step. If PID is not within specification, a large leak ispresent. See DTC P0455.

FUEL EVAPORATION (MPV)

System Inspection


57/64

Fig. 49: FTP1SV SpecificationCourtesy of Mazda Motors Corp.

3) Subtract FTP1SV from FTP2SV. Check specification. SeeFig. 50. If specification is okay, test is complete. If specificationis not within specification, a small leak is present. See DTC P0442.

Fig. 50: FTP2SV Minus FTP1SV SpecificationCourtesy of Mazda Motors Corp.

NOTE: Test must be performed within 10 minutes and without starting engine. Do not exceed 6.4 kPa pressure in EVAP system.


58/64

Whole System Test Disconnect vacuum hose from catch tank to purge solenoidvalve at valve. Connect hose to vacuum pump. Connect scan tool. SelectON BOARD DEVICE CONTROL. Return to scan tool main menu and select PIDmonitor. Select FTP PID. Apply 1.7 kPa vacuum. Vacuum should hold forat least two minutes. If vacuum does not hold, check FTP sensor.Replace as necessary. If sensor is okay, replace hose and go toCharcoal Canister-To-Purge Solenoid Test.

NOTE: Test must be performed within 10 minutes and without starting engine. Do not exceed 6.4 kPa pressure in EVAP system.

Charcoal Canister-To-Purge Solenoid Test Check hose condition and routing between charcoal canisterand purge solenoid valve. Repair as necessary. Disconnect vacuum hosefrom fuel tank to charcoal canister at canister. Connect hose tovacuum pump. Connect scan tool. Select ON BOARD DEVICE CONTROL. Return

to scan tool main menu and select PID monitor. Select FTP PID. Apply1.7 kPa vacuum. Vacuum should hold for at least t

Documents

System Component Tests