Hard Failures

Hard failures cause CHECK ENGINE light (if equipped) to illuminate and remain on until the malfunction is repaired. If light comes on and remains on (light may flash) during vehicle operation, determine cause of malfunction using diagnostic (code) charts. If a sensor fails, ECU will use a substitute value in its calculations to continue engine operation. In this condition, (fail-safe mode) the vehicle runs but driveability will not be optimum and engine speed is restricted (2000-3000 RPM depending on model).