Initial Inspection and Diagnostic Overview

INSPECTION AND VERIFICATION

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

Vacuum Inspection Chart:

2. Visually inspect for obvious signs of mechanical or electrical damage.
3. As pinpoint tests are being carried out, be sure to inspect for any disconnected, loose fitting, or incorrectly installed component, module and in-line electrical connectors and pins.
4. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
5. If the cause is not visually evident, connect the diagnostic tool to the data link connector (DLC) and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
- check that the program card is correctly installed.
- check the connections to the vehicle.
- check the ignition switch position.

6. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.
7. Carry out the DATA LINK DIAGNOSTICS test. If the diagnostic tool responds with:
- CKT 914 or CKT 915 = ALL ECUS NO RESP/NOT EQUIP, refer to Module Communications Network (Information Bus).
- SYSTEM PASSED, retrieve and record continuous diagnostic trouble codes (DTCs), erase the continuous DTCs, and carry out the self-test diagnostics for the EATC module. Reading and Clearing Diagnostic Trouble Codes
- If the electronic automatic temperature control module cannot be accessed by the diagnostic tool, GO to Pinpoint Test E. Test E

8. If the DTCs retrieved are related to the concern, go to the Powertrain Control Module Diagnostic Trouble Code (DTC) Index or the Electronic Automatic Temperature Control (EATC) Module Diagnostic Trouble Code (DTC) Index. Powertrain Control Module (PCM) Diagnostic Trouble Code Index Electronic Automatic Temperature Control Module DTC Index
9. If no DTCs related to the concern are retrieved, GO to Symptom Chart. Symptom Related Diagnostic Procedures