HVAC System - Automatic: Other Chevrolet Captiva I facelift

Sensor Resistance Table

Sensor Resistance Table

Scheme 55

Scheme 56

Scheme 57

Scheme 58

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)
2. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)

Electrical Information Reference

1. «Circuit Testing»(ref-490227-S13587550022012072700000)
2. «Connector Repairs»(ref-490227-S17487895862012072700000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-490227-S34368910942012072700000)
4. «Wiring Repairs»(ref-490227-S26043121642012072700000)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Outside Air Temp. Raw parameter. The reading should be between -35 and +85°C (-39 and +185°F) and change with air temperature changes.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Ambient Air Temperature Sensor Replacement»(ref-490214-S08752119632012072700000)
2. «Control Module References»(ref-490222-S10733352112012072700000) for HVAC control module replacement, setup, and programming

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)
2. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)

Electrical Information Reference

1. «Circuit Testing»(ref-490227-S13587550022012072700000)
2. «Connector Repairs»(ref-490227-S17487895862012072700000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-490227-S34368910942012072700000)
4. «Wiring Repairs»(ref-490227-S26043121642012072700000)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool Inside Air Temp. Sensor or the appropriate Duct Actual parameter. The reading should be between -35 and +98°C (-39 and +208°F) and change with inside passenger compartment or upper/lower air duct air temperature changes.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Inside Air Temperature Sensor Replacement»(ref-490257-S18674113252012072700000)
2. «Duct Air Temperature Sensor Replacement - Upper»(ref-490257-S01521463412012072700000)
3. «Duct Air Temperature Sensor Replacement - Lower»(ref-490257-S00868801692012072700000)
4. «Control Module References»(ref-490222-S10733352112012072700000) for HVAC control module replacement, setup, and programming

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)
2. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)

Electrical Information Reference

1. «Circuit Testing»(ref-490227-S13587550022012072700000)
2. «Connector Repairs»(ref-490227-S17487895862012072700000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-490227-S34368910942012072700000)
4. «Wiring Repairs»(ref-490227-S26043121642012072700000)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the appropriate scan tool Sunload Sensor parameter. The reading should be between 5 and 250 counts and change with sunlight changes.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Automatic Control Ambient Light Sensor Replacement»(ref-490211-S10814059482012072700000)
2. «Control Module References»(ref-490222-S10733352112012072700000) for HVAC control module replacement, setup, and programming

Schematic Reference

1. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)
2. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)
3. «HVAC Schematics»(ref-490257-S26816463832012072700000)

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)
2. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)

Electrical Information Reference

1. «Circuit Testing»(ref-490227-S13587550022012072700000)
2. «Connector Repairs»(ref-490227-S17487895862012072700000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-490227-S34368910942012072700000)
4. «Wiring Repairs»(ref-490227-S26043121642012072700000)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, command the appropriate actuator in both directions with a scan tool. The scan tool Door Position parameter reading should be between 5 and 250 counts.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Inlet Valve Actuator Replacement»(ref-490257-S26436262782012072700000)
2. «Mode Valve Actuator Replacement»(ref-490257-S42547978502012072700000)
3. «Temperature Valve Actuator Replacement»(ref-490257-S37018361752012072700000)
4. «Control Module References»(ref-490222-S10733352112012072700000) for HVAC control module replacement, setup, and programming

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)
2. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)

Electrical Information Reference

1. «Circuit Testing»(ref-490227-S13587550022012072700000)
2. «Connector Repairs»(ref-490227-S17487895862012072700000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-490227-S34368910942012072700000)
4. «Wiring Repairs»(ref-490227-S26043121642012072700000)

Scan Tool Reference

Control Module References for scan tool information

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Conditioning (A/C) Refrigerant Low Temperature Sensor Replacement (Before February 20th 2012)»(ref-490214-S33488001042012072700000) , «Air Conditioning (A/C) Refrigerant Low Temperature Sensor Replacement (After February 20th 2012)»(ref-490214-S04266209912012072700000)
2. «Control Module References»(ref-490222-S10733352112012072700000) for HVAC control module replacement, setup, and programming

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)
2. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)

Electrical Information Reference

1. «Circuit Testing»(ref-490227-S13587550022012072700000)
2. «Connector Repairs»(ref-490227-S17487895862012072700000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-490227-S34368910942012072700000)
4. «Wiring Repairs»(ref-490227-S26043121642012072700000)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool A/C High Side Pressure parameter in the ECM. The reading should be between 0.1-4.90 volts (1-425 psi), and change with pressure.

Perform Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement»(ref-490214-S17420282262012072700000)
2. «Control Module References»(ref-490222-S10733352112012072700000) for ECM replacement, setup, and programming

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)
2. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)

Electrical Information Reference

1. «Circuit Testing»(ref-490227-S13587550022012072700000)
2. «Connector Repairs»(ref-490227-S17487895862012072700000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-490227-S34368910942012072700000)
4. «Wiring Repairs»(ref-490227-S26043121642012072700000)

Scan Tool Reference

Control Module References for scan tool information

Engine running, command the A/C compressor On and OFF using a scan tool. The A/C compressor clutch should engage and disengage as commanded.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Conditioning Compressor Replacement (L4)»(ref-490214-S11870278562012072700000) , «Air Conditioning Compressor Replacement (V6)»(ref-490214-S30988573732012072700000)
2. «Relay Replacement (Within an Electrical Center)»(ref-490221-S23842483862012072700000) , «Relay Replacement (Attached to Wire Harness)»(ref-490221-S41742508962012072700000)
3. «Control Module References»(ref-490222-S10733352112012072700000) for HVAC control module and ECM replacement, setup, and programming

Symptoms - HVAC Systems - Automatic

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)
2. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)

Electrical Information Reference

1. «Circuit Testing»(ref-490227-S13587550022012072700000)
2. «Connector Repairs»(ref-490227-S17487895862012072700000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-490227-S34368910942012072700000)
4. «Wiring Repairs»(ref-490227-S26043121642012072700000)

Scan Tool Reference

Control Module References for scan tool information

Engine running, command the A/C compressor On and OFF using a scan tool. The A/C compressor clutch should engage and disengage as commanded.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Air Conditioning Clutch Assembly Replacement»(ref-490214-S14005943222012072700000)
2. «Air Conditioning Compressor Replacement (L4)»(ref-490214-S11870278562012072700000) , «Air Conditioning Compressor Replacement (V6)»(ref-490214-S30988573732012072700000)
3. «Control Module References»(ref-490222-S10733352112012072700000) for BCM, ECM, and HVAC control module replacement, setup, and programming

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)
2. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)

Electrical Information Reference

1. «Circuit Testing»(ref-490227-S13587550022012072700000)
2. «Connector Repairs»(ref-490227-S17487895862012072700000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-490227-S34368910942012072700000)
4. «Wiring Repairs»(ref-490227-S26043121642012072700000)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, command the blower motor ON and OFF with a scan tool. Monitor/feel the operation of the blower motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Blower Motor Control Module Replacement»(ref-490214-S11999336612012072700000)
2. «Blower Motor Replacement»(ref-490214-S14734479472012072700000)
3. «Control Module References»(ref-490222-S10733352112012072700000) for HVAC replacement, setup, and programming

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Air Delivery Description and Operation»(ref-490257-S38673213302012072700000)
2. «Air Temperature Description and Operation»(ref-490257-S11306202362012072700000)

Electrical Information Reference

1. «Circuit Testing»(ref-490227-S13587550022012072700000)
2. «Connector Repairs»(ref-490227-S17487895862012072700000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-490227-S34368910942012072700000)
4. «Wiring Repairs»(ref-490227-S26043121642012072700000)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, cover the sunload sensor assembly with a shop towel or other suitable item. Verify the scan tool Right Sunload Sensor and Left Sunload Sensor parameters are within 3 counts of each other. If not within the specified range, refer to Sun Load Sensor Circuit Malfunction.
2. Measure actual outside air temperature using a thermometer. Compare this value to the scan tool Outside Air Temp. Raw parameter. The measured temperature should be within 5 degrees of parameter. If not within the specified range, refer to Ambient Air Temperature Sensor Circuit Malfunction.
3. Measure actual inside air temperature using a thermometer. Compare this value to the scan tool Inside Air Temp. Sensor parameter. The measured temperature should be within 5 degrees of parameter. If not within the specified range, refer to Inside Air Temperature Sensor Circuit Malfunction.
4. Measure actual temperature using a thermometer at each of the duct temperature sensors. Compare this value to the appropriate scan tool Duct Actual parameter. The measured temperature should be within 5 degrees of appropriate Duct Actual parameter. If not within the specified range, refer to Duct Temperature Sensor Circuit Malfunction.
5. Ignition ON, command the heater core pump ON and OFF with a scan tool. Observe the operation of heater core pump. If the heater core coolant pump does not turn on and off with each command , refer to Heater Core Coolant Pump Malfunction.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Duct Air Temperature Sensor Replacement - Upper»(ref-490257-S01521463412012072700000)
2. «Duct Air Temperature Sensor Replacement - Lower»(ref-490257-S00868801692012072700000)
3. «Inside Air Temperature Sensor Replacement»(ref-490257-S18674113252012072700000)
4. «Headlamp Automatic Control Ambient Light Sensor Replacement»(ref-490211-S10814059482012072700000)
5. «Control Module References»(ref-490222-S10733352112012072700000) for HVAC replacement, setup, and programming

Ambient Air Temperature Display Updating

The HVAC control module will not request compressor clutch engagement when the ambient air temperature display is less than 2°C (35°F). In order to inspect compressor clutch operation during cold weather conditions, the vehicle must be brought inside and the ambient air temperature display must be updated. To update the ambient air temperature display on the HVAC control module, perform the following procedure

With out Scan Tool

1. Turn ON the ignition.
2. Simultaneously press the A/C and RECIRC switches.

With Scan Tool

1. Turn ON the ignition.
2. Use the Instant OAT Update procedure in the scan tool Special Functions.

HVAC Control Components

HVAC Control Module

The HVAC control module is a non-class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive and ignition 1 voltage circuits provide power to the control module. The control module supports the following features

Mode Actuator

The mode actuator is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5-volt reference, position signal, and 2 control circuits enable the actuator to operate. The control circuit uses either a 0 or 12-volt value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 volt. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 volts. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometer's adjustable contact changes the door position signal between 0-5 volts.

The auxiliary HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, one of the control circuits is grounded. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module grounds both control circuits.

Blower Motor Control Processor

The blower motor control processor is an interface between the HVAC control module and the blower motor. The blower motor speed control, battery positive voltage and ground circuits enable the control processor to operate. The HVAC control module provides a pulse width modulation (PWM) signal to the control processor in order to command the blower motor speed. The processor supplies 12 volts to the blower motor through the blower motor voltage supply circuit. The control processor uses the blower motor ground or low reference as a low side control to adjust the blower motor speed.

Air Speed

The blower motor forces air to circulate within the vehicles interior. The vehicle operator determines the blower motors speed by placing the blower motor switch in a desired speed position. The blower motor will only operate if the blower motor switch is in any position other than OFF, and the ignition switch is in the RUN position.

Once a blower speed is selected, the blower speed remains constant until a new speed is selected.

As the requested blower speed increases, the following conditions occur

1. The HVAC control module increases the amount of time that the blower motor speed control circuit is modulated to ground.
2. The voltage and duty cycle, measured between the blower motor speed control circuit and ground, decrease.

As the requested blower speed decreases, the following conditions occur

1. The HVAC control module decreases the amount of time that the blower motor speed control circuit is modulated to ground.
2. The voltage and duty cycle, measured between the blower motor speed control circuit and ground, increase.

Afterblow

Afterblow is a feature that dries the evaporator core by operating the blower motor after the engine is turned off. This reduces the microbial growth that can create undesireable odors. The vehicle does not come with the afterblow feature enabled. If the afterblow feature is required due to an odor concern, it must be turned on by the scan tool. Certain items need to have happened for afterblow to operate

1. The A/C compressor operated on the latest key cycle.
2. The system voltage is at least 11 volts to start and 10 volts to continue to run.
3. The ignition has been in the OFF position for at least 30 minutes.

Once the above conditions have been met the following events will occur

1. The blower will run for roughly 2 minutes.
2. The recirculation door moves to the outside air position.
3. The mode valve moves to the floor position.

Air Delivery

The mode actuator controls air delivery. The HVAC control module controls the actuator in order to distribute airflow to a desired outlet. When the vehicle operator selects the defrost, mix-blend or floor positions, the A/C compressor clutch engages and the recirculation actuator will be moved to the outside air position. The flow of air during the various modes of operation is as follows

1. Panel-Outside Air and Recirculation inlet air setting, full air from Instrument Panel (I/P) outlets
2. Bi-Level-I/P and front and rear floor outlets
3. Floor-Small amount of air to the right and left side window outlets and a larger amount of air to the Front and Rear floor outlets
4. Mix-Blend-Floor and defroster outlets with a slight bleed to the I/P outlets
5. Defrost-Defrost outlets with a small amount of air to the right and left side window outlets and to the Driver Side floor outlet and a very small amount to the Rear floor outlet

HVAC Control Module

The HVAC control module is a serial data device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive and ignition 1 voltage circuits provide power to the control module. The control module supports the following features

Air Temperature Actuator

The air temperature actuator is a 5-wire bi-directional electric motor that incorporate a feedback potentiometer. Low reference, 5-volt reference, position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a 0 or 12-volt value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 volts. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 volts. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometer's adjustable contact changes the door position signal between 0-5 volts.

The HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, one of the control circuits is grounded. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module removes power from both control circuits.

Air Temperature Sensors

The air temperature sensors are a 2-wire negative temperature co-efficient thermistor. The vehicle uses the following air temperature sensors

1. Ambient Air Temperature Sensor
2. Inside air temperature sensor assembly
3. Sunload Sensor
4. Upper air temperature sensor
5. Lower air temperature sensor

A signal and low reference circuit enables the sensor to operate. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor signal voltage decreases as the resistance decreases. The sensor operates within a temperature range between -40 to +87.5°C (-40 to +190°F). The sensor signal varies between 0-5 volts.

The input of the duct air temperature sensors are different from the ambient and inside sensors. The HVAC control module converts the signal to a range between 0-255 counts. As the air temperature increases the count value will decrease.

If the HVAC control module detects a malfunctioning sensor, then the control module software will use a defaulted air temperature value. The default value for the inside air temperature sensor will be displayed on the scan tool. The default value for the duct air temperature sensors will not be displayed on the scan tool. The scan tool parameter for the duct air temperature sensors are the actual state of the signal circuit. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is corrected.

The ambient air temperature sensor mounts underhood and can be affected by city traffic, by idling, and by restarting a hot engine. Therefore, the HVAC control module filters the value of the ambient air temperature sensor for temperature display. The ambient air temperature value is updated under the following conditions

Sunload Sensor

The sunload sensor is a 2-wire photo diode. The vehicle uses left and right sunload sensors. The 2 sensors are integrated into the sunload sensor assembly. Low reference and signal circuits enable the sensor to operate. As the light shining upon the sensor gets brighter, the sensor resistance increases. The sensor signal decreases as the resistance increases. The sensor operates within an intensity range between completely dark and bright. The sensor signal varies between 0-5 volts. The HVAC control module converts the signal to a range between 0-255 counts.

The sunload sensor provides the HVAC control module a measurement of the amount of light shining on the vehicle. Bright, or high intensity, light causes the vehicles inside temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

If the HVAC control module detects a malfunctioning sensor, then the control module software will use a defaulted sunload value. This value will not be displayed on the scan tool. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is fixed. The scan tool parameter for the sunload sensor is the actual state of the signal circuit.

A/C Refrigerant Pressure Sensor

The A/C refrigerant pressure sensor is a 3-wire piezoelectric pressure transducer. A 5-volt reference, low reference, and signal circuits enable the sensor to operate. The A/C pressure signal can be between 0-5 volts. When the A/C refrigerant pressure is low, the signal value is near 0 volts. When the A/C refrigerant pressure is high, the signal value is near 5 volts.

The A/C refrigerant pressure sensor protects the A/C system from operating when an excessively high or low pressure condition exists. The engine control module (ECM) disables the compressor clutch under the following conditions

1. The A/C high side pressure is more than 2 929 kPa (425 psi).
2. The clutch will be enabled after the high side pressure decreases to less than 1 376 kPa (200 psi).
3. A/C low side pressure is less than 269 kPa (39 psi).
4. The clutch will be enabled or will allow engagement again after the low side pressure increases to more than 296 kPa (43 psi).

Evaporator Low Ambient Protection

The refrigerant temperature at the temperature sensor on the evaporator case controls cycling of the compressor clutch to prevent freezing of the evaporator core. The compressor is disabled when the temperature goes below 3°C (37°F) and vehicle speed is greater than 8 km/h (5 mph). The compressor is enabled when the temperature exceeds 4°C (40°F). The minimum cycling time off is 4 seconds.

Heating and A/C Operation

The purpose of the heating and A/C system is to provide heated and cooled air to the interior of the vehicle. The A/C system will also remove humidity from the interior and reduce windshield fogging. The vehicle operator can determine the passenger compartment temperature by adjusting the air temperature control. Regardless of the temperature setting, the following can effect the rate that the HVAC system can achieve the desired temperature

1. Recirculation
2. Difference between inside and desired temperature
3. Difference between ambient and desired temperature
4. Blower motor speed setting
5. Mode setting

The vehicle operator can activate the A/C system by pressing the A/C switch. The A/C system can operate regardless of the temperature setting.

The engine control module (ECM) will operate the A/C system automatically in FRONT DEFROST mode to help reduce moisture inside the vehicle. The A/C LED will not illuminate unless the driver presses the A/C request switch on the HVAC control module. The A/C system maybe running without the A/C LED indicator illuminated when in FRONT DEFROST mode. The HVAC system uses a compressor that incorporates a thermal switch that opens once the compressor temperature exceeds 211-217°C (380-454°F) creating an open circuit. The following conditions must be met in order for the ECM to turn on the compressor clutch

1. BCM Battery voltage between 11-16 volts A/C request from the HVAC control module
2. ECM Engine coolant temperature (ECT) is greater than 117°C (243°F). Engine speed is less than 4,760 RPM. A/C pressure is between 2,929-2,706 kPa (425-39 psi).

Once engaged, the compressor clutch will be disengaged for the following conditions

1. Throttle position is 100 percent
2. A/C pressure is more than 2,929 kPa (425 psi).
3. A/C pressure is less than 269 kPa (39 psi).
4. ECT is more than 120°C (248°F).
5. Engine speed is more than 6240 RPM.
6. Transmission shift
7. ECM detects excessive torque load.
8. ECM detects insufficient idle quality.
9. ECM detects a hard launch condition.

When the compressor clutch disengages, the compressor clutch diode protects the electrical system from a voltage spike.