What Does C1228 Mean?
The ABS module has detected that the left rear wheel speed sensor input circuit is shorted to ground. The sensor signal wires are being pulled to ground potential, preventing the module from reading any wheel speed signal. ABS, traction control, and stability control will be disabled with warning lights on.
Common Causes
40%
Damaged or chafed wiring allowing the sensor signal wire to contact vehicle ground
25%
Internally shorted left rear wheel speed sensor
20%
Water-damaged or corroded sensor connector creating a ground path
10%
ABS module connector corrosion bridging signal pin to a ground pin
5%
Internal ABS module input pull-down circuit failure
Diagnostic Steps
1
Disconnect the left rear wheel speed sensor connector and measure resistance from each signal pin to chassis ground — any reading below 10K ohms indicates a short to ground. If the short disappears, the sensor itself is shorted internally.
2
With the sensor disconnected, check the harness side for continuity to ground on both signal wires at the ABS module connector — this determines if the short is in the wiring or the module.
3
Inspect the left rear sensor wiring for damage from road debris, suspension contact, or heat from the exhaust. Pay special attention where the harness routes along the rear axle and through underbody grommets.
4
Check the sensor connector for moisture, corrosion, or packed debris that could create a conductive path to the sensor mounting bracket (ground).
5
If the harness and sensor test clean, measure resistance from the ABS module signal input pins to the module ground pin with the module disconnected to check for internal failure.
Estimated Repair Cost
$75 - $350
Parts + labor, varies by vehicle and location
The ABS module has detected that the left rear wheel speed sensor input circuit is shorted to ground. The sensor signal wires are being pulled to ground potential, preventing the module from reading any wheel speed signal. ABS, traction control, and stability control will be disabled with warning li...
The most common cause of C1228 (Speed Wheel Sensor LR Input Short Circuit To Ground) is: Damaged or chafed wiring allowing the sensor signal wire to contact vehicle ground
Typical repair costs for C1228 range from $75 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
ABS and traction control are non-functional. Normal braking is unaffected. Drive carefully and avoid aggressive braking maneuvers, especially on slippery surfaces. The vehicle is safe to operate at moderate speeds to reach a repair facility.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1228 to identify the root cause.
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Quick Info
Category
Chassis
System
ABS / Traction Control
Difficulty
Type
Manufacturer
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