ECM Fail-Safe/Back-Up Functions

Fail-Safe Function
When an abnormality occurs in a signal from a sensor, the PGM-FI ECM ignores that signal and assumes a pre-programmed value that allows the engine to continue to run.
Back-Up Function
When an abnormality occurs in the PGM-FI ECM itself, the injectors are controlled by a back-up circuit independent of the system in order to permit minimal driving.
Self-Diagnosis Function (Check Engine Warning Light)
When an abnormality occurs in a signal from a sensor, the PGM-FI ECM lights the Check Engine warning light, stores the failure code in erasable memory. When the ignition is initially turned on, the PGM-FI ECM supplies ground for the Check Engine warning light for two seconds to provide bulb test.