What Does C1230 Mean?
The ABS module has detected a complete input circuit failure on the rear center wheel speed sensor. The module is unable to read any signal from this sensor, which may be mounted on the rear differential, transfer case, or transmission output. ABS and traction control will be disabled with warning lights illuminated.
Common Causes
35%
Failed rear center wheel speed sensor (open or shorted internally)
30%
Broken wiring or disconnected connector in the rear center sensor circuit
20%
Corroded or water-damaged connector at the sensor or ABS module
10%
Damaged tone ring on the differential output or driveshaft
5%
ABS module internal input circuit failure
Diagnostic Steps
1
Check live data to confirm the rear center speed sensor reads 0 mph while the other sensors show correct speeds during a road test.
2
Locate the rear center speed sensor (typically on the rear differential housing or transmission output) and inspect the connector for physical damage, corrosion, or disconnection.
3
Measure sensor resistance across the signal pins — expect 800-2000 ohms. An open reading (infinite) or dead short indicates sensor failure.
4
Check wiring continuity from the sensor connector to the ABS module connector pins. Test for shorts to ground and shorts to battery on both signal wires.
5
If sensor and wiring test good, raise the vehicle and spin the driveshaft by hand while measuring AC voltage at the sensor connector — expect 100+ mV AC. Zero output with good resistance points to a tone ring issue.
Estimated Repair Cost
$75 - $350
Parts + labor, varies by vehicle and location
The ABS module has detected a complete input circuit failure on the rear center wheel speed sensor. The module is unable to read any signal from this sensor, which may be mounted on the rear differential, transfer case, or transmission output. ABS and traction control will be disabled with warning l...
The most common cause of C1230 (Speed Wheel Sensor Rear Center Input Circuit Failure) is: Failed rear center wheel speed sensor (open or shorted internally)
Typical repair costs for C1230 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. Standard braking is unaffected but anti-lock intervention will not occur. Safe to drive at moderate speeds to a repair facility, but avoid situations requiring hard braking on slippery surfaces.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1230 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Chassis
System
ABS / Traction Control
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
