FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.

Reading and Clearing Diagnostic Trouble Codes

The diagnostic monitor contains a microprocessor that monitors the electrical system components and connections. The monitor performs a self-check of the microprocessor internal circuits and energizes the system readiness indicator during prove out and whenever a fault occurs in the system. System electrical faults can be detected and translated into coded indicator displays. If certain faults occur, the microprocessor will disable the system by opening a thermal fuse built into the monitor. If a system fault exists and the indicator is malfunctioning, an audible tone will be heard indicating the need for service.