GM Service Manual Online
For 1990-2009 cars only

    Object Number: 238315  Size: SH
  1. Perform the trim height inspection. Refer to Trim Height Inspection in Suspension General Diagnosis.
  2. Load 250-300 lbs into the rear of the passenger compartment (enough load to activate the automatic level control air compressor), distributed evenly from left to right.
  3. Turn ON the ignition, with the engine OFF. Wait for approximately one minute for the Air Replenishment Cycle to complete.
  4. Turn OFF the ignition.
  5. Repeat the trim height inspection. Refer to Trim Height Inspection in Suspension General Diagnosis. Do not adjust the automatic level control sensor if the vehicle is within the correct trim height range.
  6. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Ensure that the vehicle is roughly level and supported by the rear wheels or axle.
  7. Notice: When diagnosis or repair requires raising the vehicle on a hoist, it is important that the rear axle remains in the normal trim height position at all times. Therefore, the hoists should support the rear wheels or axle housing. Use two additional jack stands to support the rear axle when a frame contact hoist is used or damage to the auto level control air compressor could occur.

  8. Inspect the automatic level control sensor for damage. Ensure that the automatic level control sensor link is properly connected .
  9. Important: The link must be attached to the height sensor arm and the suspension control arm during the adjustment.

  10. Loosen the lock bolt (5) that clamps the metal actuating arm (4) to the plastic actuating arm.
  11. To increase the trim height, move the plastic arm up in relation to the metal arm. To decrease the trim height, move the plastic arm down in relation to the metal arm.
  12. 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.

  13. Tighten the lock bolt.
  14. Tighten
    Tighten the lock bolt to 5 N·m (44 lb in).

  15. Perform the trim height inspection. Refer to Trim Height Inspection in Suspension General Diagnosis.

Optional Sensor Adjustment Method

Special Tool J 34825 may be used for sensor adjustment. Instructions are provided with the tool.