- Powertrain/On-Board Diagnostic System Check

Self-Diagnostic Circuit Check:

The SELF-DIAGNOSTIC CIRCUIT CHECK is an organized approach for identifying a problem caused by the on-car computer-controlled electronics. Understanding this chart and using it correctly will reduce diagnosis time and prevent the unnecessary replacement of parts. Refer to HOW TO ENTER DIAGNOSTIC MODE.

NOTES ON CHART:

1. A two second bulb check of the "Service Air Conditioning" lamp at key "ON" (and after crank) confirms battery, ignition, and ground integrity to the BCM.

2. "SERVICE ENGINE SOON" and "SERVICE VEHICLE SOON" lamp illumination during crank confirms battery, ignition, and ground integrity to the ECM.

3. The Electronic Climate Control panel (ECC) and Fuel Data Center (FDC) must be functional in order to use the SELF-DIAGNOSTIC CIRCUIT CHECK. Check if the panels illuminate and respond when the buttons are depressed.

4. After entering diagnostics, record all displayed trouble codes and note those displayed during both the first and second pass. Codes displayed during the first pass only are history, (intermittents) and may require a visual or physical inspection of circuitry to isolate. Codes displayed during the second pass are current, (hard) malfunctions which can be diagnosed using the appropriate trouble code charts. If no codes were stored refer to DIAGNOSIS BY SYMPTOM-NO CODES.