Initial Inspection and Diagnostic Overview

1. Verify the customer's concern by operating the climate control system to duplicate the condition.

Visual Inspection Chart:

2. Inspect to determine if one of the mechanical or electrical concerns apply.
3. If the inspection reveals obvious concern(s) that can be readily identified, repair as required.
4. If the concern remains after the inspection, determine the symptom and GO to Symptom Chart to continue diagnostics. Symptom Related Diagnostic Procedures
If the vehicle selection cannot be entered:
^ check that the program card is correctly installed.
^ check the connections to the vehicle.
^ check the ignition switch position.
5. If the scan tool still does not allow with the vehicle selection to be entered, refer to the scan tool manual.
6. Carry out the DATA LINK DIAGNOSTIC TEST using the scan tool. If the scan tool responds with:
^ CKT 914 and CKT 915 = ALL MODULE NO RESPONSE/NOT EQUIPPED, go to Module Communications Network (Information Bus) to diagnose the communications network concern.
^ If the Powertrain Control Module (PCM) is not listed for a communication concern, turn the A/C controls to OFF and carry out the self-test diagnostics for the PCM.

7. If any PCM Diagnostic Trouble Codes (DTCs) are retrieved and related to the concern, go to the Diagnostic Trouble Code (DTC) Index to continue diagnostics. Diagnostic Trouble Code Tests and Associated Procedures
8. If no DTCs related to the concern are retrieved, GO to Symptom Chart to continue diagnostics. Symptom Related Diagnostic Procedures