Hard Failures

Hard failures cause Malfunction Indicator Light (MIL) to illuminate and remain on until problem is repaired. If light comes on and remains on (light may flash) during vehicle operation, a Diagnostic Trouble Code (DTC) will be retained in Powertrain Control Module (PCM), also known as the Engine Control Module (ECM). Cause of malfunction must be determined by retrieving and using DTCs. See RETRIEVING CODES . If a sensor fails, control unit will use 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.