What Does C1175 Mean?
The left rear (LR) wheel speed sensor input circuit has a general failure, preventing the ABS module from reading the rotational speed of the left rear wheel. Without this signal, the ABS cannot properly modulate braking for that corner. The ABS and traction control warning lights will illuminate, and the driver will lose ABS and stability control functionality.
Safety Warning
ABS and traction control are disabled. The vehicle still has conventional brakes but cannot modulate braking on the left rear corner. Increased risk of wheel lockup or loss of traction on slippery surfaces. Drive cautiously to a repair facility and avoid aggressive braking.
Common Causes
30%
Damaged or failed left rear wheel speed sensor
30%
Broken, chafed, or corroded wiring in the LR wheel speed sensor circuit
20%
Excessive air gap between the sensor and the tone ring due to debris or rust buildup
15%
Damaged or missing teeth on the LR tone ring
5%
ABS module input circuit failure for the LR channel
Diagnostic Steps
1
Compare live data wheel speed readings for all four wheels while driving at 15-25 mph. The LR wheel should show a speed reading; if it reads 0 or is erratic, confirm the sensor circuit is at fault.
2
Inspect the LR wheel speed sensor at the knuckle or hub. Look for physical damage, a cracked sensor body, or heavy rust/debris between the sensor tip and the tone ring. Clean the sensor and tone ring with brake cleaner.
3
Disconnect the LR wheel speed sensor connector and measure sensor resistance across the two pins — typical spec is 800-2000 ohms for a passive (variable reluctance) sensor. For active (Hall-effect) sensors, check for correct supply voltage at the module connector (typically 5V or 12V).
4
Inspect the wiring from the sensor to the ABS module, paying special attention to the routing near the wheel well and suspension components where flexing causes wire fatigue.
5
Spin the left rear wheel by hand and observe the AC voltage output from a passive sensor — it should produce a clean sine wave of at least 100mV at low rotation speed. An erratic or absent signal indicates a sensor or tone ring issue.
Estimated Repair Cost
$75 - $400
Parts + labor, varies by vehicle and location
The left rear (LR) wheel speed sensor input circuit has a general failure, preventing the ABS module from reading the rotational speed of the left rear wheel. Without this signal, the ABS cannot properly modulate braking for that corner. The ABS and traction control warning lights will illuminate, a...
The most common cause of C1175 (Speed Wheel Sensor LR Input Circuit Failure) is: Damaged or failed left rear wheel speed sensor
Typical repair costs for C1175 range from $75 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
ABS and traction control are disabled. The vehicle still has conventional brakes but cannot modulate braking on the left rear corner. Increased risk of wheel lockup or loss of traction on slippery surfaces. Drive cautiously to a repair facility and avoid aggressive braking.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1175 to identify the root cause.
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Quick Info
Category
Chassis
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ABS / Traction Control
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