ECM Fail-Safe/Back-Up Functions

1. Fail-Safe Function
When an abnormality occurs in a signal from a sensor, the ECM ignores that signal and assumes a pre-programmed value that allows the engine to continue to run.
2. Back-Up Function
When an abnormality occurs in the ECM itself, the injectors are controlled by a back-up circuit independent of the system in order to permit minimal driving.
3. Self-Diagnosis Function [Malfunction Indicator Lamp (MIL)]
When an abnormality occurs in a signal from a sensor, the ECM lights the MIL and stores the failure 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.