Chevrolet Trax: HVAC System malfunction

Diagnostic Instructions

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

Diagnostic Aids

Check the following mechanical fault sources:

• Air distribution box
• Air distribution hoses/air distribution ducts

Reference Information

Schematic Reference

HVAC Schematics (Encore)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J43600 Air Conditioning Service Center

Circuit/System Verification

NOTE: Check for bulletins before proceeding.

1. Ignition ON.
2. Verify every applicable scan tool Switch parameter changes when pressing the appropriate switch on the A26 HVAC Controls.

If any parameter does not change

Replace the A26 HVAC Controls.

If all parameters change

3. Verify the blower motor operates properly with the blower motor switch in each speed position.

If the blower motor does not operate in each speed position

Refer to DTC B0193.

If the blower motor operates properly in each speed position

4. Verify the HVAC doors listed below move when pressing the appropriate switch.

• Driver Temperature
• Passenger Temperature
• Mode
• Recirculation

If any HVAC door does not move

Refer to DTC B0223, B022A, B0233, B023A, B0408, or B0418.

If all HVAC doors move

5. Install the J43600 Air Conditioning Service Center.
6. Verify the high side pressure reading on the Air Conditioning Service Center is within 10% of the scan tool ECM A/C High Side Pressure Sensor parameter

If the reading is not within 10%

Refer to DTC P0532 or P0533.

If the reading is within 10%

7. Verify the A/C High Side Pressure Sensor parameter is between 269-2929 kPa (39-425 PSI).

If the reading is not between 269-2929 kPa (39-425 PSI)

Refer to Air Conditioning (A/C) System Performance Test .

If the reading is between 269-2929 kPa (39-425 PSI)

8. Verify the scan tool parameters listed below are within 10% of ambient temperature.

• Lower Left Duct Air Temperature Sensor
• Upper Left Duct Air Temperature Sensor
• Lower Right Duct Air Temperature Sensor
• Upper Right Duct Air Temperature Sensor
• A/C Evaporator Temperature Sensor

If not within 10% of ambient temperature

Refer to DTC B0173, B0178, B0509, B0514 or B3933.

If within 10% of ambient temperature

9. Verify the scan tool parameters listed below are within 10% of actual conditions.

• Passenger Compartment Humidity
• Passenger Compartment Humidity Sensor Temperature
• Passenger Compartment Windshield Temperature

If not within 10% of actual conditions

Refer to DTC B018A, B048C, B048F, or B1395.

If within 10% of actual conditions

10. Engine ON, A/C system ON.
11. Verify cool air flows from the ducts with the temperature control in the coldest position.

If the air is not cool

1. Verify the Q2 A/C Compressor Clutch is engaged.

• If the Q2 A/C Compressor Clutch is not engaged, refer to Air Conditioning Compressor Malfunction.
• If the Q2 A/C Compressor Clutch is engaged, refer to Air Conditioning (A/C) System Performance Test .

If the air is cool

12. Verify warm air flows from the ducts with the temperature control in the warmest position.

If the air is not warm

Refer to Heating Performance Diagnostic .

If the air is warm

13. Engine OFF, ignition ON.
14. Verify the Sunload parameter changes while covering the B10B Ambient Light/Sunload Sensor with a shop towel and changes when shining a bright light on it.

If the Sunload parameter does not change

Refer to DTC B0163, B0183, or B1405.

If the Sunload parameter changes

15. Verify the actual inside air temperature, using a thermometer, is less than 3ºC (5ºF) difference from the scan tool Inside Passenger Compartment Air Temp. Sensor parameter.

If greater than a 3ºC (5ºF) difference

Refer to DTC B0163, B0183, or B1405.

If less than a 3ºC (5ºF) difference

16. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• HVAC Component Replacement Reference
• Control Module References for HVAC control module replacement, programming and setup

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