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C0512 — Right Rear Wheel Speed Sensor Circuitopen

Generic OBD-II · all makesChassis

Code C0512 indicates that the ABS control module has detected an open circuit in the right rear wheel speed sensor circuit. This means the electrical path from the sensor to the module is broken, preventing the module from receiving a speed signal from that wheel. The ABS and related stability systems will be disabled as a result.

Symptoms

What causes it — most likely first

1. Faulty right rear wheel speed sensor

The sensor itself has failed internally, often due to exposure to moisture, debris, or physical impact, causing an open circuit. This is the most common cause.

2. Damaged or corroded sensor wiring

Wiring near the sensor can become frayed, broken, or corroded from road debris, flexing, or environmental exposure, interrupting the circuit.

3. Loose or corroded sensor connector

The electrical connector at the sensor may be loose, disconnected, or have corroded terminals, preventing proper contact.

4. Open circuit in wiring harness between sensor and ABS module

A break in the wire somewhere along the harness, often due to chafing against the chassis or damage from repairs, can cause an open circuit.

5. Faulty ABS control module

Rarely, the ABS module itself has an internal fault in the circuit for that sensor input. This should only be considered after all external wiring and sensor checks are exhausted.

How it's diagnosed

  1. Visually inspect the right rear wheel speed sensor, its wiring, and connector for obvious damage, disconnection, or corrosion.
  2. Disconnect the sensor and measure its resistance with a multimeter; compare to manufacturer specifications (typically 800–2000 ohms for passive sensors). An open reading confirms a faulty sensor.
  3. Check the wiring harness between the sensor connector and the ABS module for continuity, shorts to ground, or shorts to power using a wiring diagram.
  4. Inspect the connector at the ABS module for corrosion, bent pins, or loose connections.
  5. If all wiring and sensor tests pass, use a scan tool to monitor wheel speed data while spinning the wheel; an absent signal may indicate an internal module fault.

Code facts & related codes

SystemChassis
StandardizationSAE generic — identical on every make

Frequently asked

Can I drive with a C0512 code?

The vehicle can be driven, but the ABS and stability control systems will be disabled. Braking may result in wheel lockup, especially on slippery surfaces, so drive cautiously and avoid hard braking.

Is the ABS module likely the problem?

No, the ABS module is rarely the cause. The sensor, its connector, or wiring are far more common failure points. Always rule out these simpler issues first.

Will this code clear itself after repair?

No, this is a hard fault. After fixing the open circuit, the code must be cleared with a scan tool, and the ABS module may need to see a valid signal before the warning lights turn off.

I was told to replace the PCM/ECM for this code. Is that correct?

That is almost certainly incorrect. The wheel speed sensor circuit is monitored by the ABS module, not the engine computer (PCM/ECM). Replacing the PCM will not fix an open circuit in the right rear sensor and is an unnecessary expense.