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DTC codes / C00xx · Brakes, steering and suspension / C003E

C003ERear Wheel Speed Sensor Supply

C003E indicates that the antilock braking system (ABS) control module has detected a fault in the power supply circuit for the rear wheel speed sensor. This sensor provides wheel speed data critical for ABS, traction control, and stability control, and the module monitors the voltage and current on its dedicated supply line to ensure the sensor is receiving proper power.

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

Symptoms you may notice

  • ABS warning light illuminated on the dashboard
  • Traction control or stability control warning light may also be on
  • Often no symptoms besides the warning light
  • ABS may be disabled, leading to wheel lockup during hard braking
  • Traction control may not function, causing wheel spin on slippery surfaces
  • In some cases, a slight pulsation or noise from the rear brakes during ABS activation

Common causes, most likely first

  1. Damaged or corroded wiring harness to the rear wheel speed sensor
  2. Failed rear wheel speed sensor (internal short or open circuit)
  3. Poor electrical connection at the sensor connector
  4. Faulty ABS control module (internal supply circuit issue)
  5. Blown fuse or relay supplying power to the ABS system
  6. Corrosion or damage to the sensor mounting area allowing water intrusion

How to diagnose and fix it

  1. Use a scan tool to read ABS codes and confirm C003E is current; check for other codes that may indicate a related issue.
  2. Inspect the rear wheel speed sensor wiring and connector for damage, corrosion, or loose pins; repair as needed.
  3. Measure resistance and voltage at the sensor connector according to manufacturer specifications; replace sensor if out of range.
  4. Check the ABS fuse and relay; replace if blown or faulty.
  5. Perform a voltage drop test on the supply circuit from the ABS module to the sensor to identify high resistance.
  6. If all external circuits test good, suspect the ABS control module; test or replace as required.
  7. Clear codes and perform a road test to verify the repair and ensure the light stays off.

Rear sensor supply faults often misdiagnosed

  • A common mistake is replacing the rear wheel speed sensor without checking the supply voltage; the fault may lie in the wiring or module, not the sensor itself.
  • Corrosion inside the connector can cause intermittent supply faults that only appear in wet conditions, so a visual inspection may not be enough without a load test.
  • The ABS module may set C003E if the sensor supply is shorted to ground or voltage, but the root cause could be a chafed wire hidden behind a wheel arch liner.
  • Some vehicles use a shared supply for multiple sensors; a fault in one sensor's circuit can affect others, so always check for additional codes.
  • After replacing a sensor or module, some vehicles require a calibration or relearn procedure for the ABS system to recognize the new component.

Can I keep driving with C003E?

It is generally safe to drive with C003E as long as the brake pedal feels normal and the ABS light is the only warning, but remember that ABS and traction control may be disabled. Avoid hard braking or slippery conditions, and have the fault diagnosed promptly to restore full safety system function.

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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