C0220

Code

Generic C — Chassis

ABS wheel speed sensor circuit — front left

Brand: Generic

Type: C — Chassis

Views: UK: 19 EN: 26 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged or disconnected wheel speed sensor (front left)
Broken, corroded or shorted wiring/connector between sensor and ABS module
Contaminated or magnetized sensor surface or debris on tone ring
Damaged or missing tone ring (reluctor) or excessive gap between sensor and tone ring
Faulty ABS control module or poor ground/power to sensor circuit
Wheel bearing damage affecting sensor position

Symptoms

ABS warning light and/or traction control (TCS/ESP) lamp illuminated
ABS or TCS may be disabled or operate incorrectly during braking
ABS may engage erroneously or fail to engage for that wheel
Possible speedometer/odometer anomalies on some vehicles
Intermittent fault that may change with wheel movement or temperature

What to check

Read and record DTCs with a scan tool; view live wheel speed sensor data
Visual inspection of front left sensor, mounting, tone ring, and wiring
Check sensor connector for corrosion, bent pins, or moisture
Measure sensor resistance and continuity to control module (with connector disconnected)
Back-probe sensor supply and signal wires with ignition on or spin test
Use an oscilloscope or multimeter (AC) to verify signal waveform while wheel is rotated

Signal parameters

Passive (VR) sensor: AC sine output; amplitude increases with speed (tens of mV at low speed to volts at higher speed)
Passive sensor DC resistance: typical ~500–2000 ohms (varies by design); open = infinite
Active (Hall/3-wire) sensor: 0–5 V digital square wave or 0–12 V depending on vehicle; reference supply typically 5 V
Supply/reference pin (active sensor): ~5 V with ignition ON; ground should be close to chassis ground
Signal frequency: increases proportionally with wheel speed; waveform should be regular and without dropouts

Diagnostic algorithm

Retrieve and record all ABS and chassis codes; note freeze frame and live data.
Visually inspect front left sensor, connector, wiring harness routing and tone ring for damage, debris, or rust.
With ignition off, disconnect sensor and check resistance between sensor terminations; compare to manufacturer spec or other wheels. Replace if open/short.
Check for power and ground at the sensor connector (for active sensors) with ignition ON; expected ~5 V reference and ground continuity to chassis.
Back-probe the signal wire and spin the wheel by hand (or lift vehicle safely and rotate wheel). Use a multimeter (AC) or oscilloscope to verify a clean, regular waveform.
Wiggle wiring and connectors while monitoring signal for intermittent faults. Check for short to battery/ground using an ohmmeter between signal and power/ground.
Inspect tone ring for missing or damaged teeth and verify sensor air gap meets spec. Repair or replace tone ring or hub if damaged.
Repair any wiring damage, corrosion, or poor connections. Replace the sensor if tests show open circuit, no signal, or poor waveform.
After repairs, clear codes and perform a road test while monitoring live wheel speed values to confirm normal operation and that code does not return.
If wiring and sensor check good but fault persists, consider ABS module input circuit fault and consult manufacturer procedures.

Likely causes

Wet/corroded connector at sensor causing intermittent contact
Wire chafing to chassis causing short to ground or battery
Sensor has failed electrically (open coil or failed Hall element)
Missing/broken reluctor tooth or heavy rust on tone ring
Loose or missing sensor mounting bolt causing wrong air gap

Fault status

⚠️ Status

C0220 — ABS wheel speed sensor circuit fault detected at front left wheel. The ABS control module detected an abnormal, missing, or out-of-range wheel speed signal (open, short, low amplitude, or irregular waveform).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours