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Home >> Pontiac >> 2010 >> G3 L4-1.6L >> Repair and Diagnosis >> Heating and Air Conditioning >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> HVAC - Manual >> Air Conditioning Compressor Malfunction (w/ WHB)

Air Conditioning Compressor Malfunction (w/ WHB)




Air Conditioning Compressor Malfunction (w/ WHB)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Circuit/System Description

When the A/C switch is pressed, the HVAC control assembly sends a discrete message to the engine control module (ECM) for an A/C request. This input will request the IPC to send a serial data message to the ECM to ground the A/C compressor clutch relay control circuit, which will switch the A/C CLUTCH relay. With the relay contacts closed, battery voltage is supplied to the A/C compressor clutch assembly.

Reference Information
Schematic Reference

HVAC Schematics (without WHB) (HVAC Schematics (without WHB))HVAC Schematics (with WHB) (HVAC Schematics (with WHB))
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Air Delivery Description and Operation (HVAC - Manual)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Ignition ON, observe the scan tool IPC Air Conditioning parameter. The reading should be YES.

• If not YES, setup the IPC to enable AC.

2. Observe the scan tool IPC AC Switch parameter while pressing and releasing the AC switch. The reading should change between Active and Inactive.

• If not the specified value, test or replace the HVAC control head.

Note: The following conditions must be met in order for the ECM to turn on the compressor clutch:

* The IPC is programmed for A/C enabled.
* The battery voltage is between 9-18 volts.
* The engine coolant temperature (ECT) is less than 123°C (253°F).
* The engine speed is less than 4,760 RPM.
* The engine speed is more than 600 RPM.
* The A/C high side pressure is between 2929-269 kPa (425-39 psi).
* The throttle position is less than 100 percent.
* The evaporator temperature is greater than 0°C (32°F).
* The ECM does not detect excessive torque load.
* The ECM does not detect insufficient idle quality.

4. Command the AC clutch ON and OFF with a scan tool. The AC clutch should turn ON and OFF

Circuit/System Testing

1. Ignition OFF, disconnect the A/C CLUTCH relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 86 and ground.

• If the test lamp illuminates, test the control circuit for a short to voltage.

3. Verify that a test lamp illuminates between the ignition circuit terminal 85 and ground.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or a open/high resistance.

4. Verify that a test lamp illuminates between the relay B+ circuit terminal 30 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or a open/high resistance.

5. Disconnect the harness connector at the A/C clutch coil.
6. Test for less than 1 ohm between the ground circuit terminal A and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

7. Connect the harness connector at the A/C clutch coil.
8. Connect a 10-amp fused jumper wire between the B+ circuit terminal 30 and control circuit terminal 87. Verify the A/C clutch is activated.

• If the A/C clutch does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the A/C clutch.

9. Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.
10. Command the A/C relay output function ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
• If the test lamp is always OFF, test the control circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the ECM.

11. If all circuits test normal, test or replace the A/C clutch relay.

Component Testing

1. Ignition OFF, disconnect the A/C COMP relay.
2. Test for 60-180 ohms between terminals 85 and 86.

• If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87

• If not the specified value, replace the relay.

4. Install a 30-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.

• If greater than the specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Relay Replacement (Within an Electrical Center) (Service and Repair)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming

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