Hard Failures

Hard failures cause the MIL to come on and remain on until the problem is repaired. If the light comes on and remains on (light may flash) during vehicle operation, determine cause of malfunction by following the appropriate code retrieval procedures. If a sensor fails, the PCM will use a substitute value in its calculations to continue engine operation. In this condition, known as limp-in mode, the vehicle will run but driveability will not be optimum.