Code
C1041
ALFA ROMEO
C — Chassis
Right front wheel speed sensor
Views:
UK: 5
EN: 12
RU: 7
AI status
Completed
Completed
100%
Causes
- Failed or degraded right front wheel speed sensor
- Wiring open, shorted, or intermittent at sensor or harness
- Corroded/loose connector or poor ground
- Damaged or missing teeth on the tone/reluctor ring
- Contamination (metal dust, debris) on sensor or ring
- Excessive wheel bearing play affecting sensor air gap
Symptoms
- ABS warning lamp illuminated
- Traction control/ESP warning lamp illuminated; system disabled or degraded
- ABS/TC may not operate correctly under hard braking/slip conditions
- Inconsistent or zero wheel speed reading for right front on scan tool live data
- Possible pulsation or noise from wheel area if bearing is involved
What to check
- Read ABS/ESP module freeze frame and stored codes with a scan tool
- Visually inspect right front sensor, connector, and harness for damage, corrosion, or contamination
- Spin the wheel and observe the sensor signal on a scan tool (live data) or oscilloscope
- Backprobe connector to check for reference power and ground where applicable
- Measure sensor resistance and compare to service manual spec (or check for AC voltage output while spinning for passive sensors)
- Check continuity between sensor connector and ABS module pins; wiggle harness to reveal intermittent faults
Signal parameters
- Active (Hall/elementary) sensor: produces digital/pulse waveform (0–Vref to Vref or 0–12V depending on system) — square wave with frequency proportional to wheel speed
- Passive (variable reluctance) sensor: produces AC sine/triangle pulses; amplitude and frequency increase with speed (millivolts to volts peak-to-peak)
- Exact resistance, output voltage, and pulse frequency specs vary by model — consult the vehicle service manual for manufacturer values
Diagnostic algorithm
- Connect a professional scan tool, read C1041 details and freeze-frame data; note related codes.
- Visually inspect right front sensor, connector, wiring, and tone ring for obvious damage, corrosion, or debris.
- With ignition on (engine off), backprobe connector: verify sensor supply/reference and ground (if active type) per service manual.
- Spin the wheel while watching live data or use an oscilloscope: confirm presence, amplitude and shape of pulses; look for dropouts or noise.
- Measure sensor resistance (if passive) or voltage signal while rotating; compare with manual specifications.
- Check continuity between sensor connector and ABS module pins; wiggle wiring for intermittent faults.
- Inspect tone ring and wheel bearing: repair or replace if teeth missing, ring loose, or bearing play present.
- If wiring and tone ring are OK but no proper signal, replace the right front wheel speed sensor and clear codes.
- Road test and monitor live data; verify code does not return. If it persists, consider ABS module input fault and consult detailed module diagnostics.
Likely causes
- Sensor electrical failure (open/short)
- Connector corrosion or loose pin causing intermittent signal
- Reluctor ring damage or missing teeth causing no pulse
- Sensor air gap out of spec due to wheel bearing wear or installation error
Fault status
Status
Right front wheel speed sensor circuit fault detected — ABS/ESP wheel speed input for the right-front wheel is missing or out of specification.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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