A vehicle equipped with an electric power steering (EPS) system has a persistent 'binding' or 'notchiness' felt in the steering wheel, particularly at low speeds or when turning from a stop. No DTCs are present. The technician confirms adequate battery voltage and proper EPS module power/ground. Which of the following is the MOST likely cause?
- AExcessive play in the steering rack's internal bushings.
- BContamination in the steering column's upper bearing.
- CA faulty steering torque sensor providing erratic readings.
- DAn internal fault within the EPS motor windings.
Show answer & explanationAnswer & explanation
Correct answer: B. Contamination in the steering column's upper bearing.
A 'binding' or 'notchiness' in the steering wheel, especially at low speeds or from a stop, often points to friction or wear within the steering column itself. Contamination, corrosion, or wear in the steering column's upper or lower bearings can create this sensation. Since no DTCs are present and EPS power is good, the EPS system is likely trying to assist but is fighting mechanical resistance in the column, which it cannot diagnose as a fault.
Why the other options are wrong
- A. Excessive play in steering rack internal bushings would cause looseness, wander, or clunking, not a binding or notchy feel.
- C. A faulty steering torque sensor providing erratic readings would cause inconsistent assist, sudden changes in effort, or likely set a plausibility DTC.
- D. An internal fault within the EPS motor windings would likely cause a complete loss of assist, intermittent assist, or a specific DTC related to the motor current or operation.
EPS Notchy Steering (Mechanical)
When an Electric Power Steering system has a 'notchy' or 'binding' feel in the steering wheel, particularly at low speeds and without DTCs, it often indicates mechanical friction or wear within the steering column bearings or universal joints, not an electrical EPS fault.
- Sensation felt directly through the wheel.
- No DTCs suggests mechanical resistance.
- Inspect steering column U-joints and bearings.
Memory trick: Notchy steering with no codes? Check the column's joints and bearings.