ASE A4 Suspension and SteeringSteering System Diagnosis and RepairMedium
A vehicle with an electronic power steering (EPS) system develops an intermittent loss of power assist, often accompanied by the EPS warning light illuminating briefly. The issue seems to resolve itself after cycling the ignition or driving for a short period. All wiring and connections appear visually sound. Which of the following is the MOST likely cause?
- AA failing EPS control module.
- BA corroded ground connection for the EPS system.
- CA worn steering rack internal component.
- DA faulty steering angle sensor.
Show answer & explanationAnswer & explanation
Correct answer: A. A failing EPS control module.
Intermittent electrical issues that resolve with an ignition cycle or brief driving, especially when wiring appears sound, are highly indicative of an internal fault within an electronic control module, such as the EPS control module. These modules can have internal solder joint failures or component degradation that manifests intermittently.
Why the other options are wrong
- B. A corroded ground connection would typically cause more consistent and severe electrical issues, or complete failure, rather than self-resolving intermittent problems.
- C. A worn steering rack internal component would cause mechanical symptoms like binding, clunking, or consistent heavy steering, not intermittent electrical power assist loss that resolves with an ignition cycle.
- D. A faulty steering angle sensor would typically cause a consistent loss of assist or incorrect steering response, often with specific DTCs, but less likely to be intermittent and self-resolving with ignition cycles.
Intermittent EPS Electrical Faults
Intermittent loss of electric power assist that resolves with an ignition cycle or short drive, despite sound wiring, often points to a failing EPS control module.
- Power assist is intermittent.
- Resolves with ignition cycle/driving.
- Wiring appears visually good.
- Indicates internal module fault.
Memory trick: EPS flickers, then it's fine? Module's brain might be offline!