C0665 code meaning
Left Rear Wheel Speed Sensor B Incorrect Component Installed
What C0665 means
C0665 says the part on the second left rear speed channel is not the one the module expects. No carmaker documents the code or how it identifies the part. Typical mix-ups arise at the wheel bearing. Motor magazine describes bearings whose magnetic encoder ring sits on the inboard face: pressed in the wrong way round, nothing passes the sensor and speed codes appear right after the repair, while the reversed bearing is usually ruined. On the sensor side, NXP sells the KMI25 in two variants, one for magnetised multipole rings and one for steel gear wheels, so a sensor matched to the other encoder type will not work properly. GM's PIP5094 lists C0665 merely as an earlier GM number with another meaning.
C0665 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.3 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of C0665
- Warning appears right after a bearing, hub or sensor replacement
- Redundant brake functions not available
Common causes of C0665
- Most likelyWheel bearing fitted with the encoder facing away from the sensor
- PossibleSensor made for a different encoder type or vehicle
- Less likelyReplacement hub without encoder ring fitted
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Lr wss bTone ring
What each part of C0665 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 65 | The exact fault in that area. |
What to do next
- Note C0665 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 C0665
What does C0665 mean?
C0665 means "Left Rear Wheel Speed Sensor B Incorrect Component Installed". C0665 says the part on the second left rear speed channel is not the one the module expects. It is a generic code, so it means the same on every make.
Is it safe to drive with C0665?
Drive gently and only to a workshop. With C0665 the car can go into limp mode (reduced power) to protect itself.
Will C0665 fail an emissions test?
C0665 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 C0665 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. This is a job for a workshop.
Will C0665 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.