C0241

Code

Generic C — Chassis

Wheel speed sensor circuit — intermittent or no signal

Brand: Generic

Type: C — Chassis

Views: UK: 2 EN: 10 RU: 6

AI status

Completed

ready

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Page language: EN

Causes

Damaged or disconnected wheel speed sensor
Corroded, loose or damaged sensor connector or wiring harness
Contaminated or damaged tone ring/reluctor (missing teeth, heavy rust or debris)
Open or shorted wiring between sensor and ABS module
Faulty wheel speed sensor (internal failure)
Faulty ABS/traction control module or poor module ground

Symptoms

ABS warning light and/or traction control light illuminated
Loss of ABS or traction control functions during braking or acceleration
Inconsistent speedometer reading (on some vehicles)
ABS pump or module self-test faults at system startup
Intermittent fault: may appear/disappear with steering/bump movement or temperature changes

What to check

Scan for stored and pending ABS/traction codes and freeze frame data
Visually inspect the suspect wheel hub, sensor and tone ring for damage, contamination or missing teeth
Inspect sensor connector for corrosion, bent pins, water intrusion and secure mating
Check wiring harness along its routing for chafing, pinches, and broken insulation—especially at control arm/knuckle pivot points
Backprobe sensor connector while spinning wheel or during road test to observe signal
Check ABS module grounds and power supply fuses/relays related to the ABS/traction system

Signal parameters

Passive (variable reluctance) sensor: DC resistance typically ~500–2000 Ω (vehicle-specific); produces AC voltage that increases with wheel speed (mV to >1 V peak-to-peak)
Active (hall/effect) sensor: powered by 5 V or 12 V reference; output is a square/pulsetrain ~0–5 V (or 0–12 V on some systems) with a stable reference and ground
Typical waveform: clean periodic pulses; frequency proportional to wheel speed (pulses per wheel revolution = number of tone ring teeth)
Common failure signs: intermittent flatline (no pulses), erratic amplitude, increased noise, or missing teeth pattern on scope

Diagnostic algorithm

Retrieve all ABS/traction codes and freeze frame with a capable scan tool. Note whether code is stored, pending, or current.
Identify which wheel sensor is implicated by the code or live data (which wheel channel reports no or intermittent speed).
Perform a visual inspection of the sensor, connector, tone ring/reluctor and surrounding area. Clean contaminants and inspect for missing/damaged teeth.
Wiggle test: with ignition on and engine off, wiggle the sensor wiring and connector while watching live wheel speed data for dropouts (do not short terminals).
Measure sensor resistance (passive type) with multimeter; compare to service spec. For active sensors, check reference power (5 V) at connector, ground, and output signal while spinning the wheel.
Backprobe the sensor connector and record waveform with an oscilloscope while the wheel is rotated by hand or during a low-speed road test. Look for clean repetitive pulses and consistent amplitude.
Check continuity and insulation (to ground) of the sensor wiring back to the ABS module; repair any opens, shorts, or high-resistance connections.
Inspect tone ring runout and mounting; replace or repair if teeth are missing, heavily corroded, or magnetized debris is present.
If wiring, connector and tone ring are good but signal is absent or erratic, replace the wheel speed sensor and retest. Use OEM or equivalent sensor.
If new sensor still fails and wiring checks good, suspect ABS module input or module ground; perform module power and ground checks and consult module-specific diagnostics. Clear codes and perform road test to verify repair.

Likely causes

Broken or chafed wiring at suspension pivot points or steering knuckle
Corroded connector pins (moisture intrusion) at sensor or harness splice
Debris, grease or metal shavings on tone ring disrupting signal
Sensor damaged by impact or during service (bent, cracked)
Connector pushed back out of sensor housing causing intermittent contact

Fault status

⚠️ Status

Wheel speed sensor circuit intermittent or no signal detected on one wheel. ABS/traction control may be disabled until the issue is resolved.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours

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