Chassis, generic

C0665 Left Rear Wheel Speed Sensor B Incorrect Component Installed

Check engine lightUsually off
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

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.

Likely causes

Wheel bearing fitted with the encoder facing away from the sensor
Sensor made for a different encoder type or vehicle
Replacement hub without encoder ring fitted

Symptoms

  • Warning appears right after a bearing, hub or sensor replacement
  • Redundant brake functions not available

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–500
Time0.3–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

lr wss btone ring

Related codes

C065FC0664C0557C066C

References: motor.com, nxp.com, static.nhtsa.gov.