Hard Failures

Hard failures cause MIL to illuminate and remain on until problem is repaired. If light comes on and remains on during vehicle operation, cause of malfunction must be determined by retrieving DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If a sensor fails, PCM will use 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.