Chart A2, Check Engine Light Won't Flash On Steady

With ignition switch in the ON position and engine not running, CHECK ENGINE light should always be on. With check connector terminal grounded, CHECK ENGINE light will flash on and off rapidly, or will flash any stored trouble codes. A steady CHECK ENGINE light may be a short to ground or an open diagnostic terminal.

1. Checks for a grounded light circuit.
2. Determines if problem is an open check connector terminal or a faulty ECM.

Fig 1: Flow Chart A2, Check Engine Light Won't Flash, On Steady

Courtesy of GENERAL MOTORS CORP.

Fig 2: Chart A2 Schematic, Check Eng Light Won't Flash, On Steady

Courtesy of GENERAL MOTORS CORP.