ASE A4 Suspension and SteeringSteering System Diagnosis and RepairEasy
A vehicle equipped with an electric power steering (EPS) system has a warning light illuminated on the dashboard and exhibits a complete loss of power assist. A scan tool reveals DTC C0550, indicating an internal control module fault. What is the MOST likely repair for this condition?
- AReplace the EPS motor.
- BReplace the steering column assembly.
- CReprogram the EPS control module.
- DReplace the EPS control module (often integrated).
Show answer & explanationAnswer & explanation
Correct answer: D. Replace the EPS control module (often integrated).
DTC C0550 specifically indicates an internal fault within the control module itself. In many EPS systems, the control module is integrated into the steering gear or column, making replacement of the integrated unit the typical repair.
Why the other options are wrong
- A. The motor itself is not indicated as faulty by an internal control module fault code.
- B. While the module can be in the column, the fault is with the module itself, not necessarily the entire column assembly.
- C. Reprogramming might fix software glitches, but an 'internal fault' DTC often means a hardware failure.
EPS Control Module Fault
An electronic power steering (EPS) control module fault indicates an internal malfunction within the module, often requiring replacement of the module or the component it's integrated with.
- Typically results in a warning light and loss of assist.
- Specific DTCs (e.g., C0550) point to internal module issues.
- Module replacement is the common repair, sometimes as part of a larger assembly.
Memory trick: Module faults mean module replacement.