Suspension Control ( Automatic - Electronic ): Testing and Inspection

Air Spring Damper and Level Control System, Troubleshooting










Front Air Line Installation Position





The air line has 2 markings.

Insert the air line until the front marking - arrow A - is completely covered by the union nut.

Ensure that only the second marking - arrow B - on the air line is visible.

Rear Air Line Installation Position






The rear air line is covered with shrinkable tubing.

- Insert the air line until the end of the shrinkable tubing - 2 - is in contact with the union nut - 1 -.

The end of the shrinkable tubing may be a maximum of 2 mm in front of the union nut.

Perform the following test under these conditions:

• The vehicle must be cold and can not be moved during the test.

• The room temperature should be 10-30°C and remain steady.

• The vehicle must be sitting on a level surface.

- Start engine.

- Use the vehicle level adjustment knob to move the vehicle to the highest level and then the normal level.

- Activate vehicle lift mode. Refer to => [ Vehicle Lift Mode ] Description and Operation.






- Turn off engine.

- Measure and record the vehicle height at all 4 wheels.






- After 2 hours, measure the vehicle height again, record it and compare dimension - a - to the first measurement.

If the vehicle is sitting crooked, a leakage is present at the suspension with the greatest difference between the first and second measurement.

- Use commercially available leak detection spray to test the affected air spring shock absorber and the corresponding air line in this sequence:

• Air line connections

• Pressure-holding valve

• Check the air spring shock absorber.

If no deviation is determined after 2 hours, the measurement must be repeated once more after 24 hours. After 24 hours, a deviation of up to 0.16 in is permissible.