| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. |
Note. For component location, see appropriate illustration in THEORY & OPERATION article.
Circuit Description
CMP sensor is a pick-up coil mounted in outer corner of left cylinder head, just below valve cover. A one-tooth signal plate is mounted to outer camshaft. DTC is set when either no cranking or engine running signal is received by ECM from CMP sensor. Possible causes are
- CMP sensor circuit is open or shorted.
- Defective CMP sensor.
- Defective signal plate.
- Defective ECM.
Diagnostic Aids
Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.