SMU - Revised Trim Height Inspection Procedure and Trim Height Specifications

This bulletin is being issued to revise the Trim Height Inspection Procedure and the Trim Height Specifications in the Suspension General Diagnosis sub-section of the Service Manual. Please replace the current information in the Service Manual with the following information.

The following information has been updated within SI. If you are using a paper version of this Service Manual, please make a reference to this bulletin on the affected page.

Trim Height Measurement

Trim height is a predetermined measurement relating to vehicle ride height. Incorrect trim heights can cause the vehicle to bottom out over bumps, damage to the suspension components and symptoms similar to wheel alignment problems. Check the trim heights when diagnosing suspension concerns and before checking the wheel alignment.

Perform the following before measuring the trim heights:

Important: All dimensions are measured vertical to the ground. Trim height should be within ±10 mm (±0.39 in) to be considered correct.

Use the following procedure to check the J and K dimensions:

1. Measuring the J dimension for the left and right side of the vehicle inboard of the pinch-weld flange at 544 mm (21.4 in) from the centerline of the front wheel.
2. Compare the measurement to the J specification. Refer to Trim Height Specifications.
3. If the measurement is outside of the specified range, replace the front springs. Refer to Strut, Strut Component and/or Spring Replacement in Front Suspension.
4. Using your hands, lift the rear bumper approximately 38 mm (1.59 in).
5. Gently remove your hands and allow the vehicle to lower.
6. Using your hands, jounce the rear of the vehicle downward approximately 38 mm (1.59 in).
7. Gently remove your hands and allow the vehicle to rise.
8. Measuring the K dimension for the left and right side of the vehicle inboard of the pinch-weld flange at 560 mm (22 in) from the centerline of the rear wheel.
9. Compare the measurement to the K specification. Refer to Trim Height Specifications.
10. If the measurement is outside of the specified range, replace the rear springs. Refer to Coil Spring Replacement in Rear Suspension.

The Z height dimension measurement determines the proper ride height for the front end of the vehicle. There is no adjustment procedure. Repair may require replacement of suspension components.

Use the following procedure to check the Z height dimension:

1. Using your hands, lift the front bumper approximately 38 mm (1.59 in).
2. Gently remove your hands and allow the vehicle to settle .
3. Repeat this operation a total of 3 times.
4. Measure at the bottom edge of the support flange and subtract the measurement from the lowest point of the ball stud. This will give you your Z height dimension.
5. Using your hands, jounce the front of the vehicle downward approximately 38 mm (1.59 in).
6. Gently remove your hands and allow the vehicle to settle .
7. Repeat the jouncing operation 2 more times.
8. Measure the Z height dimension.
9. The true Z height dimension number is the average of the high and the low measurements. Refer to Trim Height Specifications.

The D height dimension measurement determines the proper rear end ride height. There is no adjustment procedure. Repair may require replacement of suspension components.

Use the following procedure to check the D dimension:

1. With the vehicle on a flat level surface, lift upward on the rear bumper 38 mm (1.59 in).
2. Gently remove your hands and allow the vehicle to settle.
3. Repeat the jouncing operation 2 more times.
4. Measure the vertical distance from the bottom surface of the floor pan to the top surface of the control arm flange.
5. Repeat this task for the other side of the vehicle.
6. Using your hands, jounce the front of the vehicle downward approximately 38 mm (1.59 in).
7. Gently remove your hands and allow the vehicle to settle .
8. Repeat the jouncing operation 2 more times.
9. Measure the D height dimension.
10. The true D height dimension number is the average of the high and the low measurements. Refer to Trim Height Specifications.
11. If these measurements are out of specifications, inspect for the following conditions:

•	Worn or damaged suspension components

•	Collision damage