Diagnostic Circuit Check

Self Diagnostic System 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. This process assures that there are not BCM inputs active that would not allow the system to wake-up in the correct sequence. Are the IPC and Combo panel displays operating? If these displays are not operating, then the problem is related to power and ground circuits to the IPC, Combo panel, or BCM.

2. Is the engine control system fault lamp working? If this lamp fails to illuminate during crank, then the problem could be in the power supply circuits to the computer system.

3. The odometer displays and the engine control system lamp works. Enter diagnostics and continue with code diagnosis. If diagnostics cannot be entered, refer to CHART C-1. Is there a trouble code displayed? If a trouble code is identified using the self Diagnostics, a problem has been detected by the system which can be corrected following the appropriately numbered code chart. Codes with a prefix of "E" are ECM codes, "B" are BCM codes, "L" are Lighting codes, and "R" are SIR codes.