Diagnostic Instructions

1. Connect the scan tool to the Data Link Connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the scan tool menu. 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.
If the scan tool still does not allow the vehicle selection to be entered, refer to the scan tool manual.
2. 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 Communication System Diagnostics in Module Communications Network (Information Bus) to diagnose the network concern.
- If the Powertrain Control Module (PCM) is not listed for a communication concern, turn the A/C controls to OFF and execute the self-test diagnostics for the PCM.
- If the EATC module is not listed for a communication concern, execute the self-test diagnostics for the EATC module. On-Demand Self-Test
3. If any PCM DTCs are retrieved, and are related to the concern, go to the Powertrain Control Module Diagnostic Trouble Code (DTC) Index to continue the diagnostics. Powertrain Control Module Diagnostic Trouble Code (DTC) Index
4. If any EATC DTCs are retrieved, and are related to the concern, go to the Electronic Automatic Temperature Control (EATC) Module Diagnostic Trouble Code (DTC) Index to continue the diagnostics. Electronic A/C Control (EATC) Module Diagnostic Trouble Code
5. If no DTCs related to the concern are retrieved, go to the Symptom Chart to continue the diagnostics. Symptom Related Diagnostic Procedures
6. If the electronic automatic temperature control module cannot be accessed by the scan tool, go to Pinpoint Test A. Test A: No Communication With The Electronic Automatic Temperature Control (EATC) Module