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

Check Engine

The 'checking' indicator will illuminate when the Engine Control Module (ECM) detects a fault within the system, and sends a signal to the instrument pack (pin 22, 48-way connector). The signal line is pulled low by the ECM when a fault is detected.

The indicator lamp will illuminate during each ignition cycle, until the engine fires.