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HEATING AND A/C SYSTEM DESCRI...
2009 CR-V - - Heating and A/C System Description
The air conditioning (A/C) system removes heat from the passenger compartment by transferring heat from theambient air to the evaporator. The A/C refrigerant expands in the evaporator, and the evaporator becomes verycold and absorbs the heat from the ambient air. The blower fan pushes air across the evaporator where the heat isabsorbed, and then it blows the cool air into the passenger compartment.
This vehicle uses HFC-134a (R-134a) refrigerant, which does not contain chlorofluorocarbons. Pay attention to thefollowing service items:
Do not mix refrigerants CFC-12 (R-12) and HFC-134a (R-134a). They are not compatible.
Use only the recommended polyalkyleneglycol (PAG) refrigerant oil (SP-10) designed for the R-134a A/Ccompressor. Intermixing the recommended (PAG) refrigerant oil with any other refrigerant oil will result inA/C compressor failure.
All A/C system parts (A/C compressor, discharge line, suction line, evaporator, A/C condenser,receiver/dryer, expansion valve, O-rings for joints) are designed for refrigerant R-134a. Do not exchangewith R-12 parts.
Use a halogen gas leak detector designed for refrigerant R-134a.
R-12 and R-134a refrigerant servicing equipment are not interchangeable. Use only arecovery/recycling/charging station that is U.L.-listed and is certified to meet the requirements of SAEJ2210 to service the R-134a air conditioning systems.
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Always recover refrigerant R-134a with an approved recovery/recycling/charging station beforedisconnecting any A/C fitting.
Oil Separator
Oil emission from the A/C compressor to the A/C line is reduced by placing the oil separator in the A/Ccompressor. This results in a thinner oil film inside of the heat exchangers (A/C condenser and evaporator). Airconditioning efficiency is increased without sacrificing engine performance.
A/C Pressure Sensor
The A/C pressure sensor converts A/C pressure into electrical signals to the PCM.
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A/C System Pressure* SensorOutput
Voltage (Vout)
System OperationA/C System Pressure* SensorOutput
Voltage (Vout)
System Operation
Abnormally low pressure:Below 196 kPa(2.0 kgf/cm2, 28 psi)
Below 0.685V
The PCM disengages the compressorclutch. The radiator and condenserfans operate based on engine coolanttemperature.
Normal operating pressure:
Above 196 kPa (2.0kgf/cm2, 28 psi)
Below 1,470 kPa (15.0kgf/cm2, 213 psi)
0.686 V to1.944 V
The PCM cycles the compressorclutch based on cooling demand. Theradiator and condenser fans operateat low speed unless the enginecoolant temperature exceeds 206 °F(97 °C)
High operating pressure:
Above 1,470 kPa (15.0kgf/cm2, 213 psi)
Below 3,138 kPa (32kgf/cm2, 455 psi)
1.945 V to4.575 V
The PCM cycles the compressorclutch based on cooling demand. Theradiator and condenser fans operateat high speed.
Abnormally high pressure:More than 3,138 kPa (32kgf/cm2, 455 psi)
Above 4.575V
The PCM disengages the compressorclutch. The radiator and condenserfans operate based on engine coolanttemperature.
*: The A/C system pressure can be monitored through the climate control sensor inputdisplay function.
The response of the A/C pressure sensor is shown in the graph.
NOTE: When the refrigerant is below 196 kPa (2.0 kgf/cm2, 28 psi) or above 3,138 kPa (32 kgf/cm2, 455 psi), thePCM turns the compressor relay off to protect the A/C compressor. When the refrigerant pressure is above 1,470kPa (15.0 kgf/cm2, 213 psi), the PCM switches the radiator and A/C condenser fans to high speed.
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Heating/Air Conditioning Door Positions
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HVAC Control Unit Inputs and Outputs
CONNECTOR A
Cavity Wirecolor
Terminal name Description Signal
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Cavity Wirecolor
Terminal name Description Signal
3 ORN Mode controlmotor 1 Mode control motor position
feedback
With ignition switch ON (II), or vehicle inON mode: about 0 V or about 5 V
(depending on motor position)
4 LT GRN Mode controlmotor 2 Mode control motor position
feedback
With ignition switch ON (II), or vehicle inON mode: about 0 V or about 5 V
(depending on motor position)
5 PUR Mode controlmotor 3 Mode control motor position
feedback
With ignition switch ON (II), or vehicle inON mode: about 0 V or about 5 V
(depending on motor position)
6 LT BLU S5V Power source for sensors With ignition switch ON (II): about 5.0 V
7 BLU Mode controlmotor 4 Mode control motor position
feedback
With ignition switch ON (II), or vehicle inON mode: about 0 V or about 5 V
(depending on motor position)
8 GRY Air mix controlmotor
Detects air mix potentialsignal
With ignition switch ON (II): about 0.5-4.5V (depending on AIR MIX MOTOR position)
9 BRN EvaporatorTemperatureSensor
Detects evaporatortemperature sensor signal
With ignition switch ON (II), or vehicle inON mode: between 1.0 V and 4.0 V
(depending on evaporator temperature).About 2.5 V at 72 °F (22 °C)
10 WHT ACS A/C signal
11 BLU Blower Feedback Feedback signal fromblower power resistor
With ignition switch ON (II), or vehicle inON mode, and fan switch OFF: about 8 V.Voltage decreases as fan speed increases
12 RED Blower TransistorControl Outputs blower power
resistor gate voltage
With ignition switch ON (II), or vehicle inON mode, and fan switch at MIN: about 4
V. Voltage increases to about 12 V with fanswitch at MAX
14 GRN Illumination (-) Detects illumination controlsignal
With combination light switch ON: voltagevaries as dashlights brightness varies
18 BLK Ground for HVACcontrol unit (G503)
Ground for control unit(G503)
Less than 0.5 V at all times
19 LT GRN Sensor ground Common ground for sensors Less than 0.5 V at all times
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Cavity Wirecolor
Terminal name Description Signal
20 LT GRN Rear windowdefogger relay
Input rear window defoggerrelay
21 GRN Recirculationcontrol motor(REC)
Drives recirculation controlmotor to RECIRCULATE
With ignition switch ON (II), or vehicle inON mode, and motor moving toRECIRCULATE: battery voltage
22 WHT Recirculationcontrol motor(FRS)
Drives recirculation controlmotor to FRESH
With ignition switch ON (II), or vehicle inON mode, and motor moving to FRESH:
battery voltage
23 PNK Air mix controlmotor (HOT) Drives air mix control motor
to HOT
With ignition switch ON (II), or vehicle inON mode, and motor moving to HOT:
battery voltage
24 LT BLU Air mix controlmotor (COOL) Drives air mix control motor
to COOL
With ignition switch ON (II), or vehicle inON mode, and motor moving to COOL:
battery voltage
25 LT GRN Mode controlmotor (VENT) Drives mode control motor
to VENT
With ignition switch ON (II), or vehicle inON mode, and motor moving to VENT:
battery voltage
26 GRN Mode controlmotor (DEF) Drives mode control motor
to DEF
With ignition switch ON (II), or vehicle inON mode, and motor moving to DEF:
battery voltage
27 BRN IG2 (Power) IG2 Power source With ignition switch ON (II), or vehicle inON mode: battery voltage
28 GRY Illumination (+) Input voltage forillumination
With combination light switch ON: batteryvoltage
Portions of materials contained herein are sourced from American Honda Motor Inc., Co.
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