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DTC codes / C07xx · Brakes, steering and suspension / C0730

C0730Electric Power Steering Motor Position Sensor Circuit

The C0730 code indicates that the electric power steering (EPS) control module has detected an implausible or missing signal from the motor position sensor circuit, which tracks the rotational position of the assist motor. The computer sets this code when the sensor voltage or signal pattern falls outside the expected range during key-on or while the steering assist is active.

SystemChassis
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyProfessional
AreaBrakes, steering and suspension

Symptoms you may notice

  • The power steering warning light or a message such as 'Power Steering Assist Fault' appears on the dashboard.
  • Steering effort may increase noticeably, especially at low speeds or during parking maneuvers.
  • The steering assist may cut in and out intermittently, causing a variable feel through the steering wheel.
  • In some cases, the system enters a fail-safe mode and reduces or disables power assist entirely.
  • Often no symptoms besides the warning light, with normal steering feel retained.

Common causes, most likely first

  1. A faulty motor position sensor or its internal wiring inside the EPS motor assembly.
  2. Damaged, chafed, or corroded wiring in the sensor circuit between the EPS module and the motor.
  3. Loose or corroded electrical connectors at the EPS motor or control module.
  4. A failing EPS control module that cannot correctly interpret the sensor signal.
  5. Mechanical binding or damage within the steering column or motor assembly that affects sensor readings.
  6. Water intrusion or contamination in the EPS motor housing causing sensor malfunction.

How to diagnose and fix it

  1. Perform a visual inspection of the EPS motor and control module connectors for corrosion, looseness, or damage.
  2. Check the sensor circuit wiring for continuity, shorts to ground, and shorts to voltage using a digital multimeter.
  3. Verify the sensor reference voltage and signal voltage at the EPS control module connector with the key on.
  4. Inspect the steering column and motor assembly for mechanical binding or abnormal play that could affect sensor output.
  5. Use a scan tool to monitor live motor position sensor data while turning the steering wheel to check for erratic or missing signals.
  6. If the sensor signal is confirmed faulty, replace the motor position sensor or the EPS motor assembly as required by the manufacturer.
  7. After repair, clear the code and perform a steering angle sensor calibration or EPS system relearn if specified by the vehicle manufacturer.

Before you replace the EPS motor

  • A weak or failing battery can cause the EPS module to set this code due to low voltage during cranking, so always check battery health and charging system first.
  • The motor position sensor is often integrated into the EPS motor assembly and may not be serviceable separately, leading to unnecessary motor replacement when only a connector or wire is at fault.
  • After any steering column or EPS component replacement, a steering angle sensor calibration is usually required to prevent related codes and ensure proper assist.
  • This code can be set by a simple loose ground connection for the EPS module, so inspect and clean all grounds in the engine bay and under the dash.
  • Some vehicles require a specific drive cycle or steering sweep to complete self-calibration after clearing the code, so the light may not go out immediately.

Can I keep driving with C0730?

You can usually continue driving with this code, but be prepared for a sudden increase in steering effort if the assist fails completely. Avoid high-speed maneuvers or towing until the fault is repaired, and have the system checked promptly to prevent a loss of power steering.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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