Inspection and Verification
Climate Control System
Inspection and Verification
1. Verify the customer concern by operating the climate control system to duplicate the condition.
2. Inspect to determine if one of the following mechanical or electrical concerns apply:
Visual Inspection Chart
a A leak in the vacuum control circuit may occur during acceleration (slow leak), may exist at all times (large leak) and may exist only when specific functions are selected (indicating a leak in that portion of the circuit). The vacuum hoses used in the passenger compartment control circuit are constructed from PVC plastic material. The vacuum hoses used in the engine compartment are constructed of Hytrel(R). Because of the materials used, never pinch the vacuum hoses off during diagnosis to locate a leak. A wooden golf tee can be used as a plug when it is necessary to plug one end of the vacuum hose for leak test purposes.
3. If the inspection reveals obvious concern(s) that can be readily identified, repair as required.
4. NOTE: Make sure to use the latest scan tool software release.
If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).
5. NOTE: The Vehicle Communication Module (VCM) LED prove out confirms power and ground from the DLC are provided to the VCM.
If the scan tool does not communicate with the VCM:
- check the VCM connection to the vehicle.
- check the scan tool connection to the VCM.
- refer to Information Bus, No Power To The Scan Tool, to diagnose no power to the scan tool.
6. If the scan tool does not communicate with the vehicle:
- verify the ignition key is in the ON position.
- verify the scan tool operation with a known good vehicle.
- refer to Information Bus to diagnose no response from the PCM.
7. Carry out the network test.
- If the scan tool responds with no communication for one or more modules, refer to Information Bus.
- If the network test passes, retrieve and record Continuous Memory Diagnostic Trouble Codes (CMDTCs).
8. Clear the continuous DTCs and carry out the self-test diagnostics for the PCM.
9. NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to the PCM DTC Chart. A L L Diagnostic Trouble Codes ( DTC )
If the DTCs retrieved are related to the concern, go to the PCM DTC Chart. A L L Diagnostic Trouble Codes ( DTC )
10. If not DTCs related to the concern are retrieved, GO to Symptom Chart - Climate Control Systems or GO to Symptom Chart - NVH. Symptom Chart - Climate Control Systems Symptom Chart - NVH
A/C Performance Check
1. Place the vehicle in the shade with the hood open and windows down in an enclosed shop area to minimize wind gust and sunload. Make sure the right front footwell is free of obstruction.
2. With the engine running at idle, select MAX A/C (RECIRC) and set the temperature control to full cool with the blower speed set to medium (Position 2).
3. Measure the ambient temperature and humidity adjacent to the passenger side mirror, at approximately evaporator core height.
4. With all vents opened, place a thermometer in the left center register and allow the temperature to stabilize for 6 to 8 minutes.
5. Record 5 vent temperature readings at the center register within 5 minutes.
6. Calculate the average center vent temperature.
1. Add the 5 recorded vent temperature readings to obtain the sum.
2. Divide the sum of the vent temperature readings by 5 to obtain the average center vent temperature.
7. Compare the average center vent temperature to the A/C Performance Chart for the ambient conditions at the time of testing.
- If the average center vent temperature is less than the temperature in the A/C Performance Chart, no further diagnosis is required.
- If the average center vent temperature is greater than the temperature in the A/C Performance Chart, GO to Symptom Chart - Climate Control Systems. Symptom Chart - Climate Control Systems
A/C Performance Chart
