Initial Inspection and Diagnostic Overview

HVAC PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE

For a complete wiring diagram, refer to the Wiring Information.

Perform the following steps prior to any diagnostic procedure(s).

NOTE: An HVAC Actuator Calibration using a scan tool should not be performed unless either the controller or an actuator has been replaced. DTC detection is disabled during an HVAC Actuator Calibration.

- Testing should only be performed with the battery fully charged to avoid false diagnosis.
- With the scan tool, read Powertrain Control Module (PCM) Diagnostic Trouble Codes (DTCs). If PCM DTCs are present, and perform the appropriate diagnostic procedure(s) before proceeding. A L L Diagnostic Trouble Codes ( DTC ).
- Depending on the vehicle configuration, with the scan tool, read Body Control Module (BCM) DTCs. If BCM DTCs are present, perform the appropriate diagnostic procedure(s) before proceeding. A L L Diagnostic Trouble Codes ( DTC ).
- With the scan tool, read HVAC DTCs. Record all Stored, Active, and Pending DTC information.
- With the scan tool, read the Environmental Data. Use this data to help identify the conditions in which the DTC was set.
- Refer to the When Monitored and Set Conditions for this DTC. DTCs can set at ignition on, at start up, or operating under specific conditions.
- Using the wiring diagram as a guide, inspect the wiring and connectors related to this circuit and clean/repair as necessary.
- Check for controller software updates if applicable. Some conditions can be corrected by upgrading the controller software.
NOTE: If the controller is updated with new software, with the scan tool, perform a HVAC Actuator Calibration.

- Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply.

Did any of the above procedures repair the vehicle?

Yes

- Testing is complete.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- A L L Diagnostic Trouble Codes ( DTC ) Perform the appropriate diagnostic procedure.