Edmunds Answers



  • bronconvict 11/12/08 12:49 am PST

    Perhaps the reset they are talking about is the reprogramming of height within the 4wheel airs suspension control module (4WAS Module). Its essentially the suspension brain. It is possible you didn't need to change the compressor. Sometimes resetting the height configurations on the 4WAS Module is all that is necessary. Of course the dealer won't tell you that.

    Here is some information from the shop manual:

    4-Wheel Air Suspension (4WAS) Module

    NOTE: The 4WAS module must receive a ride height adjustment calibration and must pass a pneumatic test

    when it is installed new or swapped.

    The 4-wheel air suspension (4WAS) module controls the air compressor motor (through an

    electromechanical or solid state relay), all air spring solenoids, and provides power to front and rear height

    sensors. The 4WAS module also controls vehicle height adjustments by monitoring the three height sensors

    and other universal bus protocol (UBP) signals. The 4WAS module conducts all fail-safe and diagnostic

    strategies, and contains self-test and communication software for testing the vehicle and related


    The 4WAS module monitors and controls the air suspension system through a 26-pin, two-way connector.

    The 4WAS module is keyed so that it cannot be plugged into an incorrect harness. There are two harness

    Hope it helps.


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