C0050 Code: Right Rear Wheel Speed Sensor Circuit
The ABS module can't trust the passenger-side rear wheel speed signal and has shut ABS off.
Safety first · Consult a professional
- Braking system affected: ABS may be disabled. Drive carefully and have it checked promptly.
At a glance
Severity: Moderate
- Meaning
- Right Rear Wheel Speed Sensor Circuit
- System
- Brakes, ABS & Chassis · Chassis
- Safe to drive?
- With caution
- Typical repair cost
- $80–$650
- DIY difficulty
- Moderate
C0050 is set when the brake module finds the right rear (passenger-side rear) wheel speed signal missing, erratic or electrically out of range; both GM-style numbering and the SAE list tie this number to the right rear sensor. On rear-wheel and all-wheel-drive vehicles the sensor usually reads a toothed ring pressed onto the axle shaft or rear CV joint, and those rings crack or get pushed out of round by rust. On solid rear axles, gear oil leaking past a worn axle seal can soak the sensor and brakes. Once C0050 is stored, ABS, traction and stability control are disabled until the signal is repaired and verified on a drive.
Can I keep driving? Normal braking still works, but without ABS a locked right rear wheel can make the tail slide, especially when towing or on wet roads. Drive carefully and avoid towing heavy loads until it's fixed.
How to read C0050
- C Chassis
- 0 Generic (SAE)
- 0 Brakes, ABS & Chassis
- 50 Specific fault
Symptoms
- ABS, traction and stability warnings on together
- Light appears above a certain speed and clears after a restart
- Clicking or rhythmic ABS activity at low speed from the rear
- Oily residue on the inside of the right rear wheel or brake backing plate
- Four-wheel-drive or AWD warning on vehicles that use wheel speeds for torque split
- Code appeared after a trailer hitch or wiring was installed
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Cracked, rust-swollen or loose tone ring on the axle shaft or rear CV joint
- Harness damaged near the subframe, exhaust heat shield or during hitch/trailer wiring installation
- Failed right rear sensor
- Gear oil or grease from a leaking axle seal or bearing contaminating the sensor
- Corroded connector where the rear harness joins the body
- Rear wheel bearing with excessive play
- ABS module input fault
Diagnosis step by step
Look for a once-per-revolution dropout
Graph the right rear wheel speed with a scan tool at a steady 20-30 mph. A dip that repeats at the same interval as the wheel turns points to a cracked or bent tone ring, while random dropouts point to wiring.
Tools: OBD-II scanner
Swap-test the rear sensors
Rear sensors are often the same part left and right. Swap them, clear the code and drive; if the fault moves to the left rear as C0045, the sensor is bad, and if it stays on the right, the ring, bearing or wiring is to blame.
Tools: Screwdriver, OBD-II scanner
Inspect the tone ring closely
Raise the wheel and rotate it slowly while looking at the ring through the sensor hole or with the rotor removed. Look for a hairline crack, missing teeth or a section pushed out by rust; a cracked ring is replaced with the axle shaft or CV joint on many vehicles.
Tools: Flashlight
Check for oil at the axle end
On solid axles, look for gear oil on the backing plate and sensor. A leaking axle seal must be fixed and the brakes cleaned, or the sensor will foul again and the brake shoes or pads will be contaminated.
Tools: Flashlight, Gloves
Check the harness near the hitch and exhaust
Follow the lead toward the body, paying attention to spots near the exhaust and any aftermarket trailer wiring. Measure continuity from the sensor connector to the ABS module while wiggling the harness.
Tools: Multimeter, Flashlight
Repair and confirm
After the repair, clear codes and drive past about 25 mph with some gentle turns and braking. Confirm all four speeds track together in live data before calling it fixed.
Tools: OBD-II scanner
Where the parts are
- 1Battery
- 2Alternator
- 3Engine computer (ECM)
- 4CAN bus
- 5Transmission
- 6Wheel speed sensor
- 7High-voltage battery
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Replace right rear wheel speed sensor | Yes | $80–$260 |
| Repair harness or connector | No | $90–$260 |
| Replace tone ring (on axle shaft or CV joint) | No | $150–$600 |
| Replace axle seal, clean brakes, refit sensor | No | $200–$500 |
| Replace rear wheel bearing or hub | No | $250–$650 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Field data
| Chevrolet | 2 | Hhr, Silverado 1500 |
|---|
Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.
Emissions / smog test impact
Depends
C0050 doesn't fail an OBD emissions check on its own. Where a state safety inspection applies, an ABS warning light that stays on may cause a rejection.
Frequently asked questions
Which wheel does C0050 refer to?
The right rear, which is the passenger-side rear wheel on US vehicles. The left rear is C0045, and some trucks with a single rear sensor use C0055 instead.
Why swap the rear sensors instead of just testing one?
Many active sensors can't be judged with a meter alone, and rear sensors are often identical. Swapping sides is a free test: if the code follows the sensor, you've found the bad part without guessing.
Can a cracked tone ring really cause an ABS light?
Yes. Each missing or split tooth makes the signal dip once per revolution, which the module reads as the wheel momentarily slowing. Rust under a pressed-on ring is a common cause on older vehicles in salt-belt states.
Will towing make this worse?
Towing doesn't damage the sensor, but without ABS a locked rear wheel under a heavy trailer can start a slide. Postpone heavy towing until the code is fixed.
Sources
- SAE J2012 – Diagnostic Trouble Code Definitions
- Manufacturer public service information (cross-checked)
- NHTSA Complaints API
- Methodology: How We Build Code Pages · Data Sources We Use · Editorial Policy