What Does C1141 Mean?
This code indicates the ABS control module has detected a missing tooth fault on the left front wheel speed sensor tone ring. The module analyzes the AC waveform pattern from the wheel speed sensor and has identified an irregularity consistent with a physically damaged or missing tooth on the reluctor ring. This is a mechanical fault in the tone ring itself rather than an electrical sensor failure.
Safety Warning
ABS and traction control are likely disabled. The system cannot accurately monitor left front wheel speed, increasing stopping distance on slippery surfaces. Repair promptly.
Common Causes
40%
Cracked or broken tone ring with missing teeth due to corrosion or impact, commonly from road debris
25%
Heavy rust buildup on tone ring teeth creating uneven gaps and mimicking a missing tooth signal
20%
Incorrect sensor-to-tone-ring air gap from bearing wear or sensor mounting issues
15%
Metallic debris adhering to the sensor magnetic tip, distorting the signal waveform
Diagnostic Steps
1
Step 1: Remove the left front wheel and visually inspect the tone ring for damaged, cracked, or missing teeth. Slowly rotate the hub and examine every tooth around the full circumference.
2
Step 2: Clean the tone ring with a non-metallic brush and solvent to remove corrosion and debris. Clean metallic particles from the sensor face.
3
Step 3: Check the sensor air gap with a feeler gauge (typical spec 0.020-0.050 inches). Check for wheel bearing play that could cause variable air gap by rocking the wheel assembly.
4
Step 4: Connect an oscilloscope to the LF wheel speed sensor and slowly rotate the hub by hand. Observe the waveform for consistent peak spacing. A missing tooth appears as a wider gap between peaks.
5
Step 5: Replace the tone ring or hub assembly if damage is confirmed, clear codes, and road test above 15 mph verifying stable LF wheel speed data.
Estimated Repair Cost
$150 - $500
Parts + labor, varies by vehicle and location
This code indicates the ABS control module has detected a missing tooth fault on the left front wheel speed sensor tone ring. The module analyzes the AC waveform pattern from the wheel speed sensor and has identified an irregularity consistent with a physically damaged or missing tooth on the reluct...
The most common cause of C1141 (Wheel Speed Sensor LF Tone Ring Tooth Missing Fault) is: Cracked or broken tone ring with missing teeth due to corrosion or impact, commonly from road debris
Typical repair costs for C1141 range from $150 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
ABS and traction control are likely disabled. The system cannot accurately monitor left front wheel speed, increasing stopping distance on slippery surfaces. Repair promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1141 to identify the root cause.
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Quick Info
Category
Chassis
System
Anti-lock Brake System (ABS) / Traction Control System
Difficulty
Type
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