C0664

Code

Generic C — Chassis

Left Rear Wheel Speed Sensor B Correlation

Brand: Generic

Type: C — Chassis

Views: UK: 28 EN: 40 RU: 29

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged or contaminated left rear wheel speed sensor
Broken, shorted, corroded or disconnected wiring/connectors to the sensor
Missing, damaged or dirty tone ring (reluctor) or magnet on the hub/axle
Wheel bearing or hub damage affecting sensor gap or tone ring alignment
Faulty ABS/traction control module or internal sensor input circuit
Poor ground or power supply to the sensor circuit

Symptoms

ABS warning light illuminated; traction/stability warning may also be on
ABS/traction control functions may be disabled or operate intermittently
Possible incorrect vehicle speed reporting or sporadic speedometer behavior
Pulsation or instability under braking when ABS should activate
Fault stored in ABS module; potential limp mode for stability systems

What to check

Use a scan tool to read stored freeze-frame data and live wheel speed sensor values (left rear A/B and other wheels).
Visually inspect the left rear sensor, connector, wiring harness, and tone ring for damage, contamination or missing teeth.
Wiggle test wiring and connector while monitoring live sensor signal for intermittent changes.
Measure sensor circuit resistance and compare to specification (manufacturer values) or check AC output while rotating wheel for a VR sensor.
Check sensor supply voltage and ground presence for active (Hall) sensors with ignition on.
Check for related module communication codes (CAN/U codes) and verify module grounds/power.

Signal parameters

Hall-effect/active sensors: digital square/pulse signal typically 0–5 V (or 0.5–4.5 V) synchronized with wheel rotation; frequency increases with speed.
Variable-reluctance (VR) sensors: AC sine output; amplitude increases with speed. Low speed may produce low millivolt range; higher speeds produce higher mV/V.
Typical DC resistance (sensor dependent): Hall sensors have low internal resistance; VR sensors often show hundreds to a few thousand ohms — consult vehicle spec.
Correlation expectation: left rear sensor B should produce pulses/frequency and phase consistent with left rear sensor A (or other wheel sensors) at the same wheel speed. Large amplitude, frequency, or timing mismatches indicate correlation fault.
Common trigger condition: sustained mismatch between redundant channels or between left rear and other wheel speed signals beyond manufacturer tolerance.

Diagnostic algorithm

Connect a professional scan tool. Record the C0664 freeze frame and monitor live wheel speed sensor data for all four wheels while rotating each wheel by hand or during a low-speed road test.
Perform a visual inspection of the left rear sensor, tone ring, connector, and wiring conduit for damage, corrosion, debris, or incorrect routing. Repair obvious issues.
Backprobe the sensor connector (or unplug and test as directed by manual) to confirm sensor supply (for active sensors) and ground with ignition ON. Do not short pins. If supply or ground is missing, trace power/ground circuit.
With wheel lifted and safe to rotate, check sensor output: measure AC voltage for VR sensors while spinning the wheel, or observe digital pulse voltage for Hall sensors with an oscilloscope or scan tool. Compare to other wheels.
Perform a wiggle/stress test on harness and connector while observing live data to find intermittent faults. Repair or replace wiring/connector if intermittent.
Check tone ring condition and sensor air gap. Clean deposits, correct gap per spec, or replace damaged tone ring or hub assembly.
If wiring and tone ring are good but signal is out of specification, replace the left rear wheel speed sensor with a known-good part and retest.
If new sensor shows same fault, inspect ABS module inputs, grounds, and CAN communications. Check for additional module codes and consult wiring diagrams; consider module bench testing or replacement per manufacturer guidance.
After repair, clear codes, perform a road test while monitoring wheel speed signals, and confirm C0664 does not return.

Likely causes

Corroded connector or pin/back-shell damage at the left rear sensor
Sensor contaminated with metal debris/grease or physically damaged
Tone ring cracked, missing teeth, warped, or filled with debris
Wire chafed where it passes the suspension or hub leading to intermittent short/open
Failed sensor (open, short, or out-of-spec output)
ABS module input fault or poor module ground

Fault status

⚠️ Status

ABS/traction control lamp illuminated. Fault logged in ABS module as Left Rear Wheel Speed Sensor B correlation fault. Freeze-frame and live wheel speed data available. Possible loss or mismatch of left rear wheel speed input.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours

Repair manuals