Hard Failures

Hard failures cause the malfunction indicator light 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 TROUBLE CODES procedures. If a sensor fails, the ECM 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.