C0039 code meaning
Right Rear Tone Wheel
What C0039 means
Covers the right rear tone wheel (reluctor or encoder ring) read by the right rear wheel speed sensor, completing the four-corner tone-wheel set with C0030, C0033 and C0036. 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. Ford documents the right rear sensor group including this corner on 2021 Bronco and Ranger vehicles with an illuminated ABS warning. A fault disables ABS, traction and stability control and lights the ABS warning lamp while base braking remains; electronic brake-force distribution is affected where it uses the rear sensors.
C0039 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 C0039
- ABS warning lamp on
- ABS and stability control disabled
- Grinding noise from wheel hub
Common causes of C0039
- Most likelyDamaged or contaminated tone ring
- PossibleLoose or displaced hub bearing
- 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
Rr tone wheel
What each part of C0039 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 39 | The exact fault in that area. |
What to do next
- Note C0039 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 C0039
What does C0039 mean?
C0039 means "Right Rear Tone Wheel". Covers the right rear tone wheel (reluctor or encoder ring) read by the right rear wheel speed sensor, completing the four-corner tone-wheel set with C0030, C0033 and C0036. It is a generic code, so it means the same on every make.
Is it safe to drive with C0039?
Drive gently and only to a workshop. With C0039 the car can go into limp mode (reduced power) to protect itself.
Will C0039 fail an emissions test?
C0039 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 C0039 to fix?
Difficulty: medium. A typical repair takes 0.8 to 2.5 hours of work. This is a job for a workshop.
Will C0039 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.