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DTC codes / C00xx · Brakes, steering and suspension / C0043

C0043Right Front Wheel Speed Sensor Circuit High

C0043 means the anti-lock brake system (ABS) module has detected an abnormally high voltage on the right front wheel speed sensor circuit, which usually indicates an open circuit, a short to voltage, or a sensor that is not producing a proper signal. The computer expects the sensor to pull the signal line to a specific voltage range as the wheel turns, and a high reading tells it the circuit is not behaving as designed.

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

Symptoms you may notice

  • The ABS warning light is illuminated on the dashboard, often accompanied by the traction control and stability control lights.
  • The ABS system is disabled, so the wheels can lock during hard braking and the vehicle may skid.
  • Traction control and stability control systems may stop working, reducing grip on slippery surfaces.
  • A scan tool may show no wheel speed reading for the right front wheel while other wheels show normal speeds.
  • Often no symptoms besides the warning light, especially if the fault is intermittent and the sensor occasionally produces a signal.
  • In some vehicles, the speedometer or cruise control may act erratically if the ABS module shares wheel speed data with other systems.

Common causes, most likely first

  1. A damaged or corroded right front wheel speed sensor connector, allowing the signal circuit to go open or short to voltage.
  2. A broken, chafed, or open wire in the right front wheel speed sensor harness, often near the strut, steering knuckle, or where the harness flexes with suspension movement.
  3. A failed right front wheel speed sensor that no longer produces a consistent signal, causing the module to see a high voltage condition.
  4. Excessive air gap between the sensor tip and the tone ring due to a worn wheel bearing, damaged knuckle, or incorrect sensor installation.
  5. A damaged or dirty tone ring (reluctor ring) on the right front hub or CV joint that prevents the sensor from generating a proper signal.
  6. A short to voltage on the signal circuit from another wire in the harness, often caused by rubbing against a metal edge or a faulty component sharing the circuit.
  7. A faulty ABS control module, though this is less common and should only be suspected after all circuit and sensor tests pass.

How to diagnose and fix it

  1. Inspect the right front wheel speed sensor connector and harness for corrosion, loose pins, or obvious damage, and clean or repair as needed.
  2. Disconnect the sensor and measure resistance across the sensor terminals; compare to the manufacturer's specification, which is typically in the 1,000 to 2,500 ohm range for many magnetic sensors.
  3. Check the sensor signal circuit for continuity to ground and for short to voltage using a multimeter, wiggle-testing the harness while watching the reading.
  4. Remove the sensor and inspect the tone ring for cracks, missing teeth, or heavy contamination, and clean or replace the ring if damaged.
  5. Check the air gap between the sensor and tone ring with a feeler gauge, and verify the wheel bearing is not loose or noisy, which can alter the gap.
  6. If the sensor and wiring test good, use a scan tool to monitor live wheel speed data while driving; an erratic or missing right front signal confirms a sensor or tone ring fault.
  7. Replace the right front wheel speed sensor if all circuit tests pass but the signal remains faulty, then clear codes and verify the repair with a test drive.

What a high voltage reading really tells you

  • A high voltage code often means the signal circuit is open, not that the sensor is producing too much voltage; the ABS module pulls the signal line up and expects the sensor to pull it down, so an open circuit looks like a high voltage.
  • Corroded or water-intruded connectors at the wheel speed sensor are a leading cause of this code, especially on vehicles driven in salt-belt regions or through deep water.
  • A worn wheel bearing can change the air gap between the sensor and tone ring, causing an intermittent high voltage signal that may not set a code until the vehicle is driven at higher speeds.
  • Do not replace the ABS module based on this code alone; the module is rarely the cause, and a thorough circuit test will almost always find the fault elsewhere.
  • After replacing a sensor or repairing wiring, the ABS module may need a recalibration or a short drive cycle before the light clears, and some vehicles require a scan tool to reset the learned wheel speed values.

Can I keep driving with C0043?

You can usually drive the vehicle with the warning light on, but remember that the anti-lock braking system is disabled, so avoid hard braking and slippery conditions where wheel lockup could occur. Have the fault diagnosed promptly, especially if the traction control or stability control lights are also on, as those systems may also be inactive.

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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