ASE A4 Suspension and SteeringSuspension System Diagnosis and RepairHard
A technician is diagnosing a luxury vehicle with an active suspension system that uses continuously variable dampers. The customer reports that the vehicle feels 'floaty' and exhibits excessive body roll during cornering, despite selecting the 'Sport' driving mode. A diagnostic scan reveals no active DTCs related to the suspension system. Which of the following is the MOST likely cause of these symptoms?
- AA software glitch requiring a control module reflash
- BIncorrectly calibrated ride height sensors after a suspension repair
- CA faulty steering angle sensor preventing proper mode activation
- DWorn adaptive shock absorber internal valves or fluid
Show answer & explanationAnswer & explanation
Correct answer: D. Worn adaptive shock absorber internal valves or fluid
A 'floaty' feel and excessive body roll, even in 'Sport' mode, with no DTCs, points to a mechanical failure within the continuously variable dampers themselves. Worn internal valves or degraded damping fluid would prevent the dampers from stiffening sufficiently, regardless of the control module's commands, leading to a loss of damping control and the described symptoms.
Why the other options are wrong
- A. A software glitch is possible, but without any DTCs or other erratic behavior, a mechanical failure of the damper's internal components is more probable for a consistent lack of damping.
- B. Incorrectly calibrated ride height sensors would primarily affect ride height or cause a system fault, not necessarily a fundamental loss of damping across all modes without a DTC.
- C. A faulty steering angle sensor might affect cornering strategies, but 'floaty' and excessive body roll suggests a fundamental lack of damping, and it would likely set a DTC.
Continuously Variable Dampers
These dampers use electronic control to adjust damping force in real-time, adapting to driving conditions and driver input. Internal wear can lead to loss of damping capacity.
- Feature adjustable internal valves or magnetic fluid
- Controlled by suspension control module
- Failure results in poor ride quality and handling, even without DTCs
Memory trick: Variable damper's failed, the ride is now sailed.