HVAC System Malfunction

HVAC System Malfunction

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.

Diagnostic Aids

Check the following mechanical fault sources:

* Air distribution box

* Air distribution hoses/air distribution ducts

Reference Information

Schematic Reference

HVAC Schematics Electrical Diagrams

Connector End View Reference

Component Connector End Views A/C Compressor Clutch

Description and Operation

Air Delivery Description and Operation Air Delivery

Air Temperature Description and Operation Air Temperature

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 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. 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 Blower Motor Malfunction Blower Motor Malfunction

• If the blower motor operates properly in each speed position

2. Verify all HVAC doors move when pressing the appropriate switch.

* Temperature

* Bi-Level mode

* Recirculation

• If any HVAC door does not move
Refer to DTC B0223, B0233, B0248, B0268, B0408, B0418, or B0428 B0223.

• If all HVAC doors move

3. Install the J43600 - ACR Air Conditioning Service Center.

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

• If the reading is not within 10%
Refer to DTC P0532 or P0533 P0532.

• If the reading is within 10%

5. 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 (LFX) Air Conditioning (A/C) System Performance Test (LFX).

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

6. Engine ON, A/C system ON.

7. Verify cool air flows from the ducts with the temperature control in the coldest position.

• If the air is not cool
Verify the compressor clutch is engaged.

• If the compressor clutch is not engaged
Refer to DTC P0645 P0645.

• If the compressor clutch is engaged
Refer to Air Conditioning (A/C) System Performance Test (LFX) Air Conditioning (A/C) System Performance Test (LFX).

• If the air is cool

8. 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 Heating Performance Diagnostic.

• If the air is warm

9. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.