Common signs include a stiff or heavy steering wheel, a warning light on the dashboard, and sudden or intermittent loss of steering assist. These cues warrant prompt inspection to avoid a potential safety risk.
Electric power steering (EPS) uses an electric motor and torque sensors to provide steering assist, replacing the traditional hydraulic pump. Faults can arise from battery issues, faulty wiring, sensor or control-module failures, or software glitches. This article outlines how to recognize the symptoms, how technicians diagnose EPS problems, and what to do if you experience a failure on the road.
Recognizing the warning signs
If you notice any of the following cues, EPS may be failing and you should have the system checked by a qualified technician.
- The steering wheel feels heavy or stiff, especially at low speeds
- A warning light for EPS or Power Steering appears on the dashboard
- Unusual noises such as whining, grinding, or clunking from the steering area
- The steering wheel does not return to center or feels loose or Wanders
- Sudden loss of steering assist or intermittent, unpredictable steering response
- Dashboard messages about EPS, service power steering, or CAN-bus issues
If you experience these signs, treat them as a potential safety concern and have the vehicle inspected soon. Ignoring EPS faults can lead to progressive loss of steering assist or other electrical faults that affect driving safety.
How to diagnose EPS faults
To confirm an EPS fault, technicians typically perform a combination of electronic diagnostics and physical inspections. The following steps illustrate a common approach.
- Retrieve and interpret Diagnostic Trouble Codes (DTCs) using an OBD-II scanner compatible with your vehicle’s manufacturer’s EPS system.
- Inspect the 12-volt battery and charging system, and verify stable voltage since EPS relies on electrical power; a weak battery can cause false positives or intermittent assist.
- Check fuses, relays, grounds, and electrical connectors at the steering column, EPS motor, and the control module for corrosion, looseness, or damage.
- Test motor current and torque sensor signals, and verify proper communication on the vehicle’s CAN bus network; look for intermittent connections or software issues.
- Update or recalibrate software and, if applicable, perform steering-angle sensor calibration or motor calibration as guided by the manufacturer.
Proper diagnosis requires specialized tools and knowledge of the specific EPS implementation for the vehicle. A trained technician will interpret codes, conduct electrical tests, and determine whether the fault lies with the motor, sensor, wiring, or the control module.
What to do if EPS fails while driving
EPS failures can reduce or remove steering assist, but many cars can still be steered with extra effort. Take these safety steps if you experience a suspected EPS fault on the road.
- Remain calm and keep both hands on the wheel; reduce speed gradually and avoid sudden maneuvers
- Move to a safe area or shoulder as soon as possible and turn on hazard lights
- Avoid hard turns, aggressive braking, or high-speed driving until the system is inspected
- Restarting the engine occasionally clears a temporary fault code, but this is not a guaranteed fix; do not rely on reboot as a solution
- Have the vehicle towed to an authorized service center if steering remains stiff, unresponsive, or the warning light stays on
Note: Some EPS systems can still be steered with reduced assist even when faulty, but the effort required to steer increases and the risk of losing assist without warning remains. Do not drive the vehicle if steering feels unpredictable.
Maintenance and prevention tips
Regular electrical system checks and timely software updates can help prevent EPS faults. Consider these practices to maintain EPS reliability.
- Keep the 12-volt battery in good health and have the charging system tested periodically
- Address any dashboard warnings promptly and have recall or software updates applied by the dealership
- Avoid aggressive driving that can stress steering components and electrical connections
- Have a qualified technician inspect steering-column sensors and the EPS motor during routine service intervals
Because EPS relies heavily on electronics, the root cause can be electrical, software, or sensor-related rather than mechanical wear alone. Expert diagnostics are often necessary to pinpoint the exact cause and determine the appropriate repair.
Summary
Electric power steering faults manifest as a heavy steering feel, warning lights, and unusual noises, or as a sudden loss of steering assist. Start with a safety-focused check of the electrical system and look up any stored trouble codes with an OBD-II scanner. If faults are confirmed or the warning light remains on, seek professional diagnosis and repair. Regular battery maintenance, software updates, and timely diagnostics can help keep EPS reliable and safe on the road.