Summary
C0050 indicates the ABS module has detected a malfunction in the right rear wheel speed sensor circuit. The module cannot obtain a valid speed signal from the right rear wheel, so it disables ABS, traction control, and stability control. The most common cause is a failed wheel speed sensor (30%), followed by wiring damage from underbody exposure (30%) and a corroded or damaged tone ring (20%). Your conventional brakes function normally — only the electronic brake-assist systems are deactivated.
Severity: High — ABS and traction control are disabled
Safe to drive: Yes, with caution — normal brakes work but ABS and traction control are inactive
Repair cost: $50–$400 depending on cause
DIY difficulty: Easy to Moderate
What does C0050 mean?
The right rear wheel speed sensor is mounted at the rear hub or knuckle assembly. It reads a toothed reluctor ring that rotates with the wheel, producing an electrical signal whose frequency is proportional to wheel speed. The ABS module uses this signal — along with the signals from the other three corners — to control wheel lockup during braking and wheel spin during acceleration.
C0050 is triggered when the ABS module determines that the right rear sensor signal is absent, erratic, or inconsistent with the other wheel speed inputs. The module expects the right rear to closely match the left rear during straight-line driving. When the signal is lost or corrupted, the module cannot safely modulate brake pressure to that wheel, so it shuts down all electronic braking functions.
The right rear position is particularly prone to wiring damage on trucks and SUVs. The harness often routes near the spare tire carrier, trailer hitch, or along the rear axle where it can contact moving suspension components. On vehicles that frequently tow trailers, the wiring can be damaged during hitch installation or by trailer tongue contact.