Debris or metallic particles stuck to the wheel speed sensor tip or the tone ring, disrupting the magnetic signal.; A damaged or corroded tone ring (reluctor ring) on the left rear hub, such as cracks, missing teeth, or excessive rust.; Wiring harness damage between the left rear sensor and the ABS module, including chafed wires, broken connectors, or water intrusion.; A failing left rear wheel speed sensor that produces an erratic signal under certain conditions like temperature changes or vibration.; Excessive air gap between the sensor and tone ring due to worn hub bearings or incorrect sensor installation.; Electrical interference from nearby components such as a failing ignition system or aftermarket electronics, though this is less common.

DTC codes / C05xx · Brakes, steering and suspension / C050D

C050DLeft Rear Wheel Speed Sensor A Range/Performance

Q: What does code C050D mean?

Left Rear Wheel Speed Sensor A Range/Performance. C050D indicates that the anti-lock brake system (ABS) module has detected an abnormal signal from the left rear wheel speed sensor, specifically a range or performance fault rather than a complete circuit failure. The computer compares the left rear sensor's signal to expected values and to the other wheel speed sensors, and it sets this code when the signal is erratic, intermittent, or outside the acceptable range for the vehicle's speed.

C050D indicates that the anti-lock brake system (ABS) module has detected an abnormal signal from the left rear wheel speed sensor, specifically a range or performance fault rather than a complete circuit failure. The computer compares the left rear sensor's signal to expected values and to the other wheel speed sensors, and it sets this code when the signal is erratic, intermittent, or outside the acceptable range for the vehicle's speed.

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 may be disabled, leading to wheel lockup during hard braking, though normal braking usually remains functional.
A pulsation or vibration through the brake pedal during braking if the ABS activates unexpectedly due to a faulty signal.
The speedometer may fluctuate or read incorrectly if the left rear sensor signal is used for vehicle speed calculation.
Often no symptoms besides the warning light, especially if the fault is intermittent and does not affect normal driving.

Common causes, most likely first

Debris or metallic particles stuck to the wheel speed sensor tip or the tone ring, disrupting the magnetic signal.
A damaged or corroded tone ring (reluctor ring) on the left rear hub, such as cracks, missing teeth, or excessive rust.
Wiring harness damage between the left rear sensor and the ABS module, including chafed wires, broken connectors, or water intrusion.
A failing left rear wheel speed sensor that produces an erratic signal under certain conditions like temperature changes or vibration.
Excessive air gap between the sensor and tone ring due to worn hub bearings or incorrect sensor installation.
Electrical interference from nearby components such as a failing ignition system or aftermarket electronics, though this is less common.

How to diagnose and fix it

Inspect the left rear wheel speed sensor and tone ring for physical damage, debris, or corrosion, and clean them if necessary.
Check the sensor's air gap and compare it to the manufacturer's specification, adjusting or replacing components if out of range.
Perform a visual inspection of the wiring harness and connectors for the left rear sensor, looking for chafing, corrosion, or loose pins.
Use a scan tool to monitor live wheel speed data from all four sensors while driving to identify erratic signals from the left rear.
Measure the sensor's resistance and compare it to the manufacturer's specification, and check for an AC voltage signal while spinning the wheel.
If the sensor and wiring are good, test the tone ring for runout and damage, and replace the hub or tone ring if defective.
As a last step, diagnose the ABS module for internal faults if all external components test good, though this is rare.

Common Oversights When Diagnosing C050D

A dirty or rusty tone ring often causes this code without any visible sensor damage, so cleaning the ring and sensor can resolve the issue without parts replacement.
Intermittent faults may only appear under specific conditions such as rough roads or temperature extremes, so a road test with live data is crucial for accurate diagnosis.
The left rear sensor signal is sometimes used for the speedometer, so a faulty sensor can cause speedometer errors that mislead diagnosis toward the instrument cluster.
Aftermarket brake or suspension work can disturb the sensor or tone ring, leading to this code if the components are not reinstalled correctly.
A weak or failing wheel bearing can alter the air gap and cause a performance code even when the sensor itself is functioning properly.

Can I keep driving with C050D?

You can usually continue driving with this code because normal braking remains functional, but the ABS and stability control systems may be disabled, reducing safety in emergency maneuvers. Avoid hard braking or driving in slippery conditions until the fault is repaired, and have the system diagnosed promptly.

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.