Symptoms
- Steering wheel suddenly feels much heavier to turn
- Power steering warning light on the dash
- Steering assist cuts in and out intermittently
- Warning message about steering assist reduced
Likely causes
- CommonFaulty steering angle or torque sensorElectric power steering relies on sensors that can fail and trigger reduced assist as a safety measure.
- CommonLow battery voltage affecting the steering moduleElectric power steering is sensitive to voltage and can reduce assist if voltage is too low.
- PossibleSteering module software faultLike other computer modules, it can develop a software glitch needing a reset or update.
- PossibleWiring or connector issue to the steering motorDamaged wiring can disrupt the signal needed for proper power assist.
What to do
- Note if the heavy steering happened suddenly or gradually, and if it coincides with other electrical symptoms.
- Check the battery and charging system, since low voltage is a common trigger for reduced steering assist.
- Try turning the car off and back on to see if the warning clears after a system reset.
- Have the steering system scanned with a code reader for stored fault codes.
- Avoid driving if steering becomes extremely difficult to control, and have the car towed instead.
- Note any unusual noises from the steering column when the issue occurs.
- Have a shop diagnose and replace a faulty sensor or module based on scan results.
- Get the battery and alternator fully checked as part of the diagnosis, since voltage issues are a common root cause.
Tools and parts
- OBD-II code reader
Steering angle sensorSearch: “steering angle sensor for [your car make model year]”
When to call a pro
Electric power steering faults should be diagnosed and repaired by a shop, since it directly affects your ability to safely control the vehicle.
Safety
Use caution
Sudden loss of power steering assist makes the car much harder to control, especially at low speeds; pull over safely if this happens while driving.