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DTC codes / C07xx · Brakes, steering and suspension / C0735

C0735Electric Power Steering Module Internal Fault

C0735 indicates that the Electric Power Steering (EPS) module has detected an internal fault within its own circuitry or firmware, not a problem with the motor, sensors, or wiring outside the module. The module's self-diagnostic routine has flagged a failure that prevents it from reliably controlling assist, so it typically disables power steering and illuminates the warning light.

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

Symptoms you may notice

  • Power steering assist may be completely lost, making the steering wheel very hard to turn, especially at low speeds
  • The power steering warning light or a generic EPS fault message appears on the dashboard
  • The steering may feel intermittently heavy or assist may cut in and out while driving
  • Often no symptoms besides the warning light, with steering assist still functioning normally
  • The vehicle may enter a fail-safe mode that limits engine power or disables other chassis features
  • A stored C0735 code is present when scanning the EPS module, sometimes with no driver complaints

Common causes, most likely first

  1. Internal failure of the EPS module's power supply circuit or microcontroller
  2. Corrupted or invalid firmware/software within the EPS module
  3. Solder joint or component failure on the EPS module circuit board due to heat or vibration
  4. Water intrusion or corrosion inside the EPS module housing
  5. Voltage spikes or low-voltage events that damaged the module's internal electronics
  6. A faulty ground connection that causes the module to self-detect an internal fault (less common but possible)

How to diagnose and fix it

  1. Verify battery voltage and charging system health, as low voltage can trigger false internal fault codes
  2. Check and clean the EPS module ground connections and inspect for corrosion or loose terminals
  3. Perform a thorough visual inspection of the EPS module and its connectors for water intrusion, bent pins, or damaged wiring
  4. Use a factory-level scan tool to read EPS module data, clear the code, and see if it returns immediately or after a drive cycle
  5. Check for any applicable software updates or recalibration procedures for the EPS module
  6. If the code persists after all external checks, replace or reprogram the EPS module following the manufacturer's procedures
  7. After repair, perform a steering angle sensor calibration and clear all related codes, then test-drive to confirm assist is restored

What the code does not always mean

  • C0735 is often set by a momentary low-voltage event, such as a weak battery during cranking, and may not indicate a permanent module failure.
  • A poor ground connection at the EPS module can mimic an internal fault, so always verify grounds before condemning the module.
  • Some vehicles store C0735 as a history code after a jump-start or battery replacement, and clearing it may be all that is needed.
  • The EPS module may share power or ground with other systems, so a fault in a related circuit can cause the module to self-report an internal error.
  • After replacing the EPS module, many vehicles require programming or calibration with a factory scan tool, or the code will return.

Can I keep driving with C0735?

If the power steering assist is lost, the vehicle is still steerable but requires significantly more effort, especially at low speeds, so avoid driving until the fault is diagnosed. If the warning light is on but assist feels normal, you may drive cautiously to a repair shop, but be prepared for a sudden loss of assist.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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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