Hard Failures
WARNING: This page is about a different car, the 1994 Plymouth Sundance, 1994 Plymouth Acclaim, 1994 Dodge Spirit, 1994 Dodge Shadow, and 1994 Chrysler LeBaron. However, it is still accessible from the selected car via links, so may be relevant.
Hard failures will cause MIL to illuminate and remain on until malfunction is repaired. If MIL comes on and remains on (or light may flash) during vehicle operation, cause of malfunction must be determined using diagnostic tests.
If a sensor fails, PCM will use a substitute value in its calculations, allowing engine operation in limp-in mode. In this condition, vehicle will run but driveability will be poor.