C1141: Left Front Wheel Speed Sensor Signal Irregularity
The C1141 code indicates that the ABS control module has detected an irregular signal from the left front wheel speed sensor, consistent with missing teeth on the tone ring (reluctor). The module monitors the frequency and pattern of the AC voltage signal generated by the sensor as the tone ring teeth pass by; missing teeth cause characteristic gaps in the signal, which the software interprets as this specific fault.
1. Commonly Affected Makes
2. Most Common Causes
- Damaged, cracked, or missing teeth on the left front wheel bearing/hub tone ring (reluctor)
- Faulty left front wheel speed sensor or incorrect air gap
- Short circuit, open circuit, or corrosion in the left front wheel speed sensor wiring or connector
- Worn left front wheel bearing causing excessive play
- Defective ABS control module (HCU/ECU) – rare
3. Symptoms You Will Notice
- ABS warning light illuminated on the dashboard
- Possible loss of ABS, traction control, or stability control functions
4. Step-by-Step Diagnosis
Scan for codes and verify C1141 is present; check for additional related codes.
Visually inspect the left front wheel speed sensor wiring and connector for damage, corrosion, or loose connection.
Remove the left front wheel and inspect the tone ring (reluctor) on the hub/bearing for missing, cracked, or damaged teeth.
Measure the air gap between the wheel speed sensor and tone ring; adjust if necessary (typically 0.5–1.5 mm).
Test the wheel speed sensor resistance and AC voltage output while spinning the wheel; compare to specifications.
If all else checks out, suspect a faulty ABS module and perform further module diagnostics.
5. Frequently Asked Questions
Is it safe to drive?▼
Driving with code C1141 is not recommended because ABS, traction control, and stability control may be disabled, increasing the risk of loss of control during emergency braking or slippery conditions. Have the vehicle inspected as soon as possible.
How much does it cost to fix?▼
Repair costs typically range from $150 to $600, depending on the root cause. A wheel speed sensor replacement is usually $150–$300, while a wheel bearing/hub assembly (including tone ring) can cost $300–$600. Diagnostic fees are extra.