Chevrolet Trax: HVAC System malfunction (C67)

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), HVAC Schematics (Trax)

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

Manual 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 ACR 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.

• Temperature
• Mode
• Recirculation

If any HVAC door does not move

Refer to DTC B0223, B0233, B023A, or B0408 (C67)

If all HVAC doors move

5. Install the J43600 ACR Air Conditioning Service Center, ignition ON.
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 HVAC 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 HVAC A/C Evaporator Temperature Sensor parameter listed is within 10% of ambient temperature.

If not within 10% of ambient temperature

Refer to DTC B3933.

If within 10% of ambient temperature

9. Verify the A/C compressor clutch engages and disengages when commanding the ECM A/C Compressor Clutch Relay On and Off with a scan tool.

If the A/C compressor does not engage

Refer to DTC P0645, P0646, or P0647

If the A/C compressor does engage

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 (C67).
• 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. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• HVAC Component Replacement Reference (C67)
• Control Module References for HVAC control module replacement, programming and setup

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