GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Remove the mounting nuts retaining the coolant recovery tank .
  2. Lift the coolant recovery tank to gain access to the camshaft position (CMP) sensor.

  3. Object Number: 256317  Size: SH
  4. Disconnect the electrical connector from the CMP sensor.
  5. Remove the CMP sensor mounting bolt (2).
  6. Remove the CMP sensor (1) from the cylinder head.
  7. • Remove the sensor by pulling on the sensor connector. DO NOT pry on the bracket.
    • DO NOT rotate or twist the sensor or damage the mounting bracket if the sensor is being reused.

Installation Procedure

Important: When replacing the CMP sensor with a new sensor or reinstalling the original sensor, use the following recommended procedures:

   • Ensure that the CMP sensor bore is completely free of any foreign material, such as old O-ring, dirt, burrs, etc.
   • Ensure that the flange on the CMP sensor bore is not damaged.
   • Clean all of the mounting surfaces before re-installing any components.
   • Inspect the CMP sensor and replace the sensor if any of the following conditions are present:
      - The bracket is damaged
      - The bottom of brass housing exhibits any damage
      - Never install a sensor that has been dropped
   • Lubricate the O-ring on the sensor with Amojell or clean engine oil prior to installing the sensor.
   • Inspect all of the connectors for any damaged terminals.


    Object Number: 256317  Size: SH
  1. Install and fully seat the CMP sensor (1) into the cylinder head.
  2. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  3. Install the CMP sensor mounting bolt (2).
  4. Tighten
    Tighten the bolt to 9 N·m (80 lb in).

  5. Connect the electrical connector to the CMP sensor.
  6. Lower the coolant recovery tank onto the mounting studs.
  7. Install the 2 mounting nuts to retain the coolant recovery tank .
  8. Tighten
    Tighten the nuts to 1 N·m (9 lb in).