C066A

Code

Generic C — Chassis

Right Rear Wheel Speed Sensor B Intermittent/Erratic

Brand: Generic

Type: C — Chassis

Views: UK: 23 EN: 30 RU: 21

AI status

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Page language: EN

Damaged or corroded wheel speed sensor
Damaged or contaminated tone/reluctor ring (missing or bent teeth, rust, debris)
Broken or chafed wiring harness / intermittent connector contact
Poor ground or reference voltage to the sensor
Intermittent short to power or ground in the sensor circuit
Water intrusion or corrosion at connector

Read freeze frame and live data with a capable scan tool; watch all four wheel speed channels while rotating the wheel or during test drive
Check for other related DTCs stored (other wheel speed sensor faults, module faults)
Visually inspect right rear sensor and tone ring for damage, debris, or missing teeth
Inspect connector for corrosion, bent pins, water ingress, and secure fit
Wiggle test wiring from hub to body while monitoring live data for intermittent changes
Measure continuity and resistance of the sensor circuit back to the ABS module (compare to OEM spec)

Passive (variable reluctance) sensors: AC voltage amplitude increases with wheel speed; low speed amplitudes often small (tenths to a few volts); frequency proportional to wheel speed
Active/Hall sensors: digital square wave output usually 0–5 V (or open-collector pulsed to supply), frequency proportional to wheel speed
Expected behavior: clean, consistent pulses with amplitude and frequency smoothly increasing with wheel speed; intermittent dropouts, noisy waveforms, or amplitude spikes indicate a fault
Tone ring: consistent number of pulses per wheel revolution; missing teeth or uneven air gap will produce irregular pulses

Retrieve DTC details and freeze frame; note conditions (speed, temperature) when fault set.
Clear codes, perform a controlled road test while monitoring all wheel speeds. Reproduce the fault if possible.
Backprobe sensor connector (or use breakout adapter) and inspect for proper supply/reference voltage and ground (if sensor is active).
With wheel lifted, spin the wheel and observe sensor signal with an oscilloscope (preferred) or multimeter (AC for VR). Look for missing pulses, noise, or intermittent loss of signal.
Inspect sensor mounting, air gap, and tone ring for debris, rust, or damaged/missing teeth. Clean if contaminated and recheck.
Perform wiggle test on harness and connector while watching live data to find intermittent opens/shorts. Repair any damaged wiring or replace connector as required.
Measure resistance of passive sensor and compare to manufacturer specification; replace sensor if out of spec or if signal is erratic despite wiring being good.
If sensor and wiring check ok but problem persists, inspect wheel bearing and hub for play that could affect air gap; repair as needed.
Replace sensor (and repair wiring/connector or tone ring) if diagnostics point to sensor circuit fault. After repair, clear codes and road test to verify.
Only consider ABS module replacement after exhaustive verification of sensor, wiring, connectors, and tone ring, as a module is rarely the root cause.

⚠️ Status

Right Rear Wheel Speed Sensor B - Intermittent/Erratic signal detected

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-3.0 hours

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