C051B code meaning
Right Rear Wheel Speed Sensor - Mechanical
What C051B means
C051B covers a mechanical defect at the right rear wheel. No public manufacturer document defines when it is set; the cases known from bulletins carry other codes. They still show what to inspect at a right rear wheel. GM's 2018 program 18316 for Express and Savana vans found that axle vibration over rumble strips shook the right rear sensor signal into erratic values, and changed the brake module calibration rather than any part. Ford's message on the F-53 chassis covers tone rings deformed while hub and rotor were refitted. Infiniti's sensor bulletin adds loose or corroded tone wheels and bearings to the list. A mechanical code therefore calls for a look at encoder, bearing and sensor fit before electrical testing.
C051B at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of C051B
- ABS, stability and traction lamps after rough stretches
- Driver aids unavailable until the next ignition cycle
Common causes of C051B
- PossibleRight rear tone ring deformed or corroded
- PossibleRight rear hub bearing loose or worn
- Less likelyAxle vibration disturbing the signal on rough surfaces
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Wss rrTone ring rr
What each part of C051B means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1B | The exact fault in that area. |
What to do next
- Note C051B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C051B
What does C051B mean?
C051B means "Right Rear Wheel Speed Sensor - Mechanical". C051B covers a mechanical defect at the right rear wheel. It is a generic code, so it means the same on every make.
Is it safe to drive with C051B?
Drive gently and only to a workshop. With C051B the car can go into limp mode (reduced power) to protect itself.
Will C051B fail an emissions test?
C051B is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C051B to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will C051B clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.