Hard Failures

Malfunction Indicator Light (MIL) will illuminate when a hard failure is detected and remain on until problem is repaired. If MIL comes on and remains on or flashes during vehicle operation, cause of malfunction must be determined. When most sensors fail, ECM will default to a substitute value in its calculations to continue engine operation. In this condition, commonly known as limp-in mode, the vehicle runs but driveability will not be optimum.