ECM Fail-Safe Back Up Functions
FAIL-SAFE FUNCTIONWhen an abnormality occurs in a signal from a sensor, the Engine Control Module (ECM) ignores that signal and assumes a pre-programmed value for that sensor that allows the engine to continue to run.
BACK-UP FUNCTION
When an abnormality occurs in the ECM itself, the fuel injectors are controlled by a back-up circuit independent of the system in order to permit minimal driving.
SELF-DIAGNOSIS FUNCTION MALFUNCTION INDICATOR LAMP (MIL)
When an abnormality occurs in a signal from a sensor, the ECM supplies ground for the MIL and stores the code in erasable memory. When the ignition is initially turned on, the ECM supplies ground for the MIL for two seconds to check the MIL bulb condition.