Ride Height Sensor: Testing and Inspection

Air Spring Sensor Calibration

1. Raise and support the vehicle. Refer to Vehicle Lifting.
2. Position the rear axle to the D-height trim specifications, plus an additional 25-35 mm (0.98-1.38 in). Refer to Trim Height Specifications.
3. Support the body in position.
4. Turn ON the ignition, with the engine OFF for 2 minutes. This will de-pressurize the rear air springs.
5. After depressurization is complete, turn OFF the ignition.
6. Remove the air suspension system fuse.
7. Remove the rear tire and wheels.





Important: A D-height block can be used to determine the D-height position. Create a D-height measurement gage, using metal stock. Cut a block to 20 mm X 30 mm X the correct D trim height specification. For the correct D-height specification, refer to Trim Height Specifications.

8. With the aid of an assistant, position the correct D-height gage blocks between the axle housing tube and the frame rail bracket. Centerline of hole on each side (2).
9. Raise the rear axle toward the frame until the D-height block contacts both rear axle housing tube and body rail (2).




10. Attempt to install an air spring level sensor locating pin. A 4 mm drill bit or rod can be substituted.

Notice: Failure to remove the air suspension auto level control sensor locating pin before the rear axle support is removed will cause damage to the air suspension auto level control sensor.

* If the pin can be inserted into each sensor, the air spring level sensors are properly positioned, and no adjustment is required.
* If the pin cannot be inserted into the sensor assembly, adjust the sensor continuing with the following steps.

11. Loosen the air spring level sensor to the frame mounting bolts.




12. Install the sensor locating pin.





Notice: Refer to Fastener Notice.

Important: Do not remove the air spring level sensor locating pin until the air spring level sensor has been properly aligned and the proper D-height has been measured and maintained. Refer to Trim Height Specifications.

13. Tighten the air spring level sensor to the frame mounting bolts.

Tighten the air spring level sensor to the frame mounting bolts to 8 Nm (71 in. lbs.).





Notice: Failure to remove the air suspension auto level control sensor locating pin before the rear axle support is removed will cause damage to the air suspension auto level control sensor.

14. Verify the pin can be removed and installed with ease to ensure correct sensor installation. If the pin cannot be inserted with ease, loosen the sensor fasteners and retighten until the pin can be eased in and out.
15. Remove the air spring level sensor locating pin.
16. Perform sensor calibration for the other side.
17. Ensure the air springs are properly positioned on the axle spring seats.
18. Install the rear tire and wheels.
19. Install the air suspension fuse.
20. Turn ON the ignition, engine OFF.

Important: If the air bags are inflated after depressurizing, an initial loud "pop" noise may be heard as the air bags are inflating. This is a normal condition.

21. Allow the air suspension to operate for several minutes to ensure that the air suspension is functioning properly.

Important: If the air springs are completely deflated, an additional ignition cycle may be required to allow the compressor to completely inflate the air springs.

22. Recycle the ignition if needed.
23. Turn OFF the ignition.
24. Lower the axle in order to remove the D-height blocks.
25. Lower the vehicle