C0656 code meaning
Left Front Wheel Speed Sensor B Correlation
What C0656 means
C0656 flags a mismatch between the B signal at the left front hub and the values it is checked against, typically sensor A on the same hub, while the circuit itself tests good. No carmaker publishes this code or its limits. Two patent designs show what such a comparison can catch. Continental Teves placed two magnetoresistive paths of different sensitivity in one housing; a comparator inside the sensor checks whether both deliver the same frequency, because a disturbed path can flip and even double the reading. Audi proposed pairing an active Hall sensor with a passive inductive one on the same pulse wheel, so that a supply failure cannot silence both. Likely causes: a damaged encoder, a sensor sitting too far from its encoder, mixed-up parts.
C0656 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of C0656
- Warning for brake or driver assistance system
- Automated or redundant brake functions withdrawn, ABS usually still active
Common causes of C0656
- Most likelySensor not seated correctly, air gap out of tolerance
- PossibleDamaged, dirty or partly demagnetized encoder ring
- Less likelySensor of a different type or side fitted
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Lf wss bLf wssTone ring
What each part of C0656 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 56 | The exact fault in that area. |
What to do next
- Note C0656 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 C0656
What does C0656 mean?
C0656 means "Left Front Wheel Speed Sensor B Correlation". C0656 flags a mismatch between the B signal at the left front hub and the values it is checked against, typically sensor A on the same hub, while the circuit itself tests good. It is a generic code, so it means the same on every make.
Is it safe to drive with C0656?
Drive gently and only to a workshop. With C0656 the car can go into limp mode (reduced power) to protect itself.
Will C0656 fail an emissions test?
C0656 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 C0656 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will C0656 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.