Inspection and Verification

Climate Control System

Inspection and Verification

NOTE: Verify the service disconnect plug is correctly inserted and locked into the LOCK position.

1. Verify the customer concern.

2. Visually inspect for obvious signs of mechanical or electrical damage.

Visual Inspection Chart






3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

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 communication with the VCM:

- check the VCM connection to the vehicle.

- check the scan tool connection to the VCM.

- refer to Module Communications Network Testing and Inspection, No Power To The Scan Tool, to diagnose no power to the VCM.

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 Module Communications Network Testing and Inspection to diagnose no response from the HVAC module, Air Conditioning Compressor Module (ACCM), Instrument Panel Cluster (IPC) or PCM.

7. Carry out the network test.
- If the scan tool responds with no communication from one or more modules, refer to Module Communications Network Testing and Inspection.

- If the network test passes, retrieve and record the Continuous Memory Diagnostic Trouble Codes (CMDTCs).

8. Clear the CMDTCs and carry out the self-test diagnostics for the HVAC, ACCM, IPC or PCM.

9. If the HVAC DTCs retrieved are related to the concern, go to the HVAC Module DTC Chart. If the ACCM DTCs retrieved are related to the concern, go to the Air Conditioning Compressor Module (ACCM) DTC Chart. If the PCM DTCs retrieved are related to the concern, go to the PCM DTC Chart. For all other DTCs, refer to Multifunction Electronic Modules Testing and Inspection. HVAC Module DTC Chart Air Conditioning Compressor Module (ACCM) DTC Chart PCM DTC Chart

If no DTCs are present, GO to Symptom Chart - Climate Control Systems for the appropriate diagnostic action. Climate Control System


HVAC Module and A/C Compressor Self-Test

During the self-test, the HVAC module will do the following:

- command airflow to PANEL vents
- command temperature blend door actuator to full cold
- set blower speed to level 4 and the 4th level will be displayed on the display
- illuminate the POWER, A/C and RECIRC button indicators
- flash the DEFROST, AUTO and rear window defrost button indicators
- command the A/C compressor to between 1,900 and 2,000 rpm

1. Start the engine.

2. Observe the Electric A/C Compressor Speed (ACCM_ECS) Air Conditioning Compressor Module (ACCM) PID.

3. At the same time, press and release the POWER and DEFROST buttons then, within 2 seconds, press the RECIRC button.

4. Observe the HVAC module actions and A/C compressor speed.

- If the airflow is incorrect, refer to Climate Control System - General Information and Diagnostics Climate Control System - General Information and Diagnostics.
- If the panel outlet temperature is incorrect, refer to Climate Control System - General Information and Diagnostics Climate Control System - General Information and Diagnostics.
- If the blower is inoperative, GO to Pinpoint Test K. Pinpoint Test K: The Blower Motor is Inoperative
- If the blower speed is incorrect, GO to Pinpoint Test L Pinpoint Test L: The Blower Motor Does Not Operate Correctly - DATC
- If one or more indicators do not illuminate but the HVAC and A/C compressor operate correctly, INSTALL a new Front Controls Interface Module (FCIM). Refer to Information and Entertainment Systems Service and Repair.
- If the ACCM_ECS PID reads 0 RPM, GO to Pinpoint Test I. Pinpoint Test I: The Air Conditioning (A/C) is Inoperative
- If the ACCM_ECS PID reads between 1 and 1,899 rpm or greater than 2,000 rpm, INSTALL a new electric A/C compressor. REFER to Climate Control Service and Repair. TEST the system for normal operation.
- If all modes in the self-test are achieved, GO to Pinpoint Test E. Pinpoint Test E: Unable to Duplicate Customer Concern and No DTCs Present

5. To exit the self-test, press any climate control button or turn the ignition OFF.