Self-Diagnostic System Check
The Self-Diagnostic System Check is an organized approach to identifying a computer-controlled electronics problem. Understanding the chart and using it correctly will reduce diagnostic time and prevent unnecessary parts replacement.
The Self-Diagnostic System Check should be used to begin diagnosis if any customer complaint does not directly relate to a specific subsystem. If the SERVICE SOON light fails to illuminate during cranking, then the problem could be in the power supply circuit of the BCM/ECM computer system. The Self-Diagnostic System Check will direct technician to an appropriate diagnostic chart.
If the CCDIC display is not operating properly, BCM/ECM COMPUTER SYSTEM SELF-DIAGNOSTICS mode CANNOT be used and the SELF-DIAGNOSTIC SYSTEM CHECK will direct technician to an appropriate diagnostic chart.
If a trouble code is identified the BCM/ECM computer system self-diagnostics mode, problem can be corrected following the appropriate numbered code chart(s). If no code has been identified, the SELF-DIAGNOSTIC SYSTEM CHECK will direct technician to an appropriate diagnostic chart.