Chassis, generic

C05F4 Rear Drive Shaft Speed Sensor Circuit Range/Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

The rear drive shaft speed is electrically valid but does not fit the rest of the driveline. The controller can compare it with wheel speeds, the axle ratio and the clutch state: with AWD engaged the shaft must follow the rear wheels, and a reading that stays near zero, lags or runs too fast is implausible. American Axle relies on a pinion shaft speed sensor to confirm that the disconnected rear driveline has reached primary speed before a dog clutch shifts, and BorgWarner times engagement by a speed difference of about 100 to 200 rpm. A wrong reading would break exactly that check. Likely causes are an enlarged air gap, a damaged target ring, a wrong part or a slipping clutch. No maker documents C05F4; electrical faults are C05F0 to C05F3.

Likely causes

Air gap too large, sensor not fully seated or wrong spacer
Target ring damaged, loose or covered with metal debris
Wrong sensor, target ring or axle ratio after repair
Slipping AWD clutch makes shaft speed deviate

Symptoms

  • AWD warning and all-wheel drive disabled
  • Rear axle no longer connects in a disconnecting AWD system
  • Live data shows shaft speed that does not match wheel speeds

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–500
Time0.5–3 h

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

Parts involved

rear drive shaft speed sensor

Related codes

C05F0C05F1C05F2C05F3

References: patents.google.com, patents.google.com, allegromicro.com.