C1D03

Code

Generic C — Chassis

ABS Rear Right Wheel Speed Sensor Circuit Fault

Brand: Generic

Type: C — Chassis

Views: UK: 6 EN: 12 RU: 7

AI status

Completed

ready

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Page language: EN

Causes

Open or short in the rear right wheel speed sensor wiring or connector
Corroded/contaminated or loose connector at sensor or ABS module
Failed wheel speed sensor (magnetic/VR or hall-type)
Damaged or missing tone ring/reluctor on hub or axle
Damaged ABS module input circuit or poor ground
Damaged wheel bearing or metallic debris interfering with tone ring

Symptoms

ABS warning lamp on (may be accompanied by traction control or stability warning)
Traction control and/or stability control degraded or disabled for that wheel
Brake pedal feel may be normal but ABS may not operate properly on hard stops
Noisy wheel bearing or grinding if tone ring/wheel bearing is damaged
Inconsistent or zero wheel speed reading for the rear right wheel on a scan tool

What to check

Read and record freeze-frame and full ABS fault data with a scan tool; note frequency and conditions
Visually inspect wiring and connector at the rear right wheel for corrosion, damage or moisture
Check for damaged/missing tone ring or debris on hub/axle and inspect wheel bearing
Compare live wheel speed sensor data for all four wheels while rolling the vehicle slowly
Backprobe connector at sensor and at ABS module to verify reference, signal and ground
Measure sensor resistance (if applicable) and continuity to the ABS module pins

Signal parameters

Variable reluctance (VR) sensor: AC voltage amplitude increases with wheel speed; weak/no AC indicates open/failed sensor. Typical idle/low speed pulses ~0.1–1.5 VAC rising with speed (specs vary by vehicle).
Hall-effect sensor: digital square wave referenced to 5 V (or battery voltage on some systems); signal toggles between ~0 V and ~5 V (or ~0–12 V on older systems).
Pulse frequency proportional to wheel speed (tens to thousands of pulses per second depending on speed and tooth count).
Typical static resistance (VR type) often between ~800–2000 ohms on many vehicles; refer to manufacturer spec.
Reference/supply voltage to hall sensors usually ~5 V (or vehicle reference); ground should be low (

Diagnostic algorithm

Read ABS codes and freeze frame; record conditions when fault set.
Visually inspect sensor, connector and tone ring for damage, contamination or missing teeth.
With connector disconnected, measure sensor resistance and compare to spec (VR type) or verify presence of reference voltage (hall type).
Backprobe the sensor connector (or use oscilloscope) and spin the wheel by hand or road test to observe output waveform and amplitude.
Verify continuity and resistance of sensor wiring from the sensor connector to the ABS module; check for shorts to ground or battery.
Check reference supply and ground at the ABS module pin while monitoring data; verify module pins are not corroded or loose.
Wiggle test wiring and suspension components while monitoring live data to reproduce intermittent faults.
If wiring and connector test OK and sensor output is abnormal, replace the wheel speed sensor and retest.
If a new sensor still shows fault and wiring is good, inspect/repair tone ring or wheel bearing as needed.
As a last step, consider ABS module input fault—verify with manufacturer diagnostic flow before replacing module.
Clear codes and perform a controlled road test to confirm repair; verify no reoccurrence of C1D03 and that wheel speed readings are consistent.

Likely causes

Contaminated or disconnected sensor connector
Broken/chafed wiring between sensor and ABS module (common with suspension travel)
Failed wheel speed sensor
Tone ring damage or heavy corrosion on ring/reluctor

Fault status

⚠️ Status

ABS Rear Right Wheel Speed Sensor Circuit Fault — signal missing or implausible (open/short/intermittent). ABS/traction control may be disabled for that wheel until repaired.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours