GM Service Manual Online
For 1990-2009 cars only
  1. Prior to measuring the vehicle trim height, prepare the vehicle as follows:
  2. Ensure that the following conditions exsist:
  3. 2.1. The fuel gage reads full.
    2.2. The spare tire and the tools are properly located.
    2.3. The vehicle is free of the ice, the snow and the mud accumulations.
  4. Set the front and the rear tire pressure to within plus or minus 20 kPa (3 psi) of the recommended pressure shown on the tire placard. If two load conditions are shown on the placard, use the lower load condition.
  5. Close the engine compartment hood and all of the doors.
  6. Up to 7 kg (15.5 lb) may be left in the trunk if the weight is located approximately on the vehicle centerline. Remove the items necessary in order to meet this requirement.
  7. Measure the vehicle trim height as follows:
  8. • Z and J Dimensions: Lift the front bumper of the vehicle up approximately 38.0 mm (1 1/2 in). Gently remove your hands and let the vehicle settle. Repeat twice for a total of 3 times. Measure Z and J dimensions. Push the front bumper down approximately 38.0 mm (1 1/2 in). Gently repeat twice for a total of 3 times. Measure Z and J dimensions. True heights are the average of the high and low measurements.
    • K dimension: Lift the rear bumper of the vehicle up approximately 38.0 mm (1 1/2 in). Gently remove your hands and let the vehicle settle. Repeat twice for a total of 3 times. Measure K dimension. Push the rear bumper down approximately 38.0 mm (1 1/2 in). Gently remove your hands and let the vehicle rise on its own. Repeat twice for a total of 3 times. Measure K dimension. True heights are the average of the high and low measurements.