The diagnostic strategy for the active suspension system control module will vary with the issue presented to the technician. For instance, if one air spring fails to inflate, the technician would likely begin by checking the hardware at that air spring or inspecting for leaks. However, if one air spring at a time randomly failed to inflate, the technician would likely begin inspection at the control module. It is less important to understand the diagnostic process for active suspension systems than it is to understand that the process differs greatly depending on the fault exhibited and other clues which may be present.

Once the control module has been recognized as the failed component, the technician will remove any obstructing covers or trim components, inspect and ensure the wiring harness and connectors for the module are in working order, and remove mounting hardware to remove the control module. Once the new control module is in place, the trim or other obstructions can be replaced and programming of the module can begin. As with most other procedures for automotive repair, the system will be tested before returning it to the customer.

We recommend thorough testing of the active suspension system before replacing any parts that are suspected of failure. Since the control module uses the inputs of the various sensors around the vehicle to perform its functions, it can easily mimic the failure of those electrical sensors and components. This has led to the costly replacements of good components on many occasions.

When diagnosing any active suspension system, the suspension must be deactivated before raising the vehicle with a jack. When the vehicle is lifted, the active suspension will attempt to level itself if left on, and this may result in damage to the active suspension system, or unstable lifting with the jack. If deactivating the system is not possible, disable the compressor.

Diagnosing and replacing the control module for many systems is outside of the scope of the DIY mechanic. This is typically due to two factors, availability of high quality and high functioning scan tools, and inexperience servicing computerized automotive systems. As stated before, the control module can mimic issues that any component of the system can cause, and the cause of the issue may not be immediately understood as part of the system. If the fault is not abundantly clear, leave diagnosis of the active suspension system to a trained professional. This will ensure the issue is diagnosed and repaired properly.