Chassis, generic

C0056 Left Rear Wheel Speed Sensor Circuit Intermittent

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

Covers an intermittent fault in the left rear wheel speed sensor circuit, where the signal is lost or corrupted only part of the time rather than permanently. The ABS/ESC module expects a clean pulse train proportional to wheel speed; a chafed wire that opens over bumps, a loose or corroded connector, a cracked sensor or a contaminated encoder ring can make the signal drop out briefly. Because the fault is sporadic it may set and self-clear, and ABS, traction and stability control drop out only during the glitches. The ABS warning lamp is set and base braking remains. Bosch active wheel speed sensors depend on a stable two-wire supply and a clean air gap to the encoder. No code-specific public bulletin was confirmed; the entry follows the SAE J2012 generic definition.

Likely causes

Chafed wire or loose connector
Cracked sensor or contaminated encoder
Excessive or varying air gap

Symptoms

  • Intermittent ABS warning lamp
  • ABS/ESC drops out briefly
  • Speedometer flickers

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–400
Time0.5–2.5 h

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

Parts involved

wheel speed sensor rlsensor wiring

Related codes

C0060C0066C0050

References: bosch-mobility.com, en.wikipedia.org.