Engine Controls - Tests W/Codes: Description
WARNING: This page is about a different car, the 1991 Cadillac Fleetwood and 1991 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
The Self-Diagnostic System Check is an organized approach to identifying a problem caused by the on-vehicle computer controlled electronics. Understanding the chart and using it correctly will reduce diagnostic time and prevent unnecessary parts replacement.
Codes displayed during the first pass are history or intermittent codes and may require a visual or physical inspection of circuitry to isolate problem. Codes displayed during the second pass are current or hard codes which can be diagnosed using procedures outlined in PCM TROUBLE CODE DIAGNOSIS or BCM TROUBLE CODE DIAGNOSIS.
The Self-Diagnostic System Check should be used to begin diagnosis if any customer complaint does not directly relate to a specific subsystem.