C003C code meaning
Rear Tone Wheel
What C003C means
Covers a single rear tone wheel (reluctor or encoder ring) on vehicles that use one combined rear wheel speed signal, for example from a differential or rear axle sensor, rather than separate left and right rear rings. It is a signal-plausibility code set when the module sees an erratic, noisy or intermittent rear speed signal consistent with a damaged, contaminated or loose tone ring rather than a sensor circuit failure. A fault disables ABS, traction and stability control and lights the ABS warning lamp while base braking remains; on such vehicles rear-based functions like electronic brake-force distribution are affected. No manufacturer documents this code publicly; NHTSA's EPS safety report lists the rear tone wheel code C003C among the J2012 wheel speed codes.
C003C at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.8 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C003C
- ABS warning lamp on
- ABS and stability control disabled
- Intermittent rear speed signal
Common causes of C003C
- Most likelyDamaged or contaminated tone ring
- PossibleLoose or displaced bearing or axle ring
- Less likelyExcessive sensor-to-ring air gap
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Rear tone wheel
What each part of C003C means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 3C | The exact fault in that area. |
What to do next
- Note C003C 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 C003C
What does C003C mean?
C003C means "Rear Tone Wheel". Covers a single rear tone wheel (reluctor or encoder ring) on vehicles that use one combined rear wheel speed signal, for example from a differential or rear axle sensor, rather than separate left and right rear rings. It is a generic code, so it means the same on every make.
Is it safe to drive with C003C?
Drive gently and only to a workshop. With C003C the car can go into limp mode (reduced power) to protect itself.
Will C003C fail an emissions test?
C003C 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 C003C to fix?
Difficulty: medium. A typical repair takes 0.8 to 2.5 hours of work. This is a job for a workshop.
Will C003C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.