C1148: Right Front Wheel Speed Sensor Coherence Fault
The C1148 code indicates a coherence fault in the right front wheel speed sensor. This sensor, which may be an inductive or Hall-effect type, generates a pulse signal representing wheel rotation speed. The ABS control module detects that the signal from the right front sensor is inconsistent with signals from other wheels or with expected vehicle dynamics. This can manifest as erratic readings, intermittent signal loss, or values that don't match actual wheel speed.
1. Commonly Affected Makes
2. Most Common Causes
- Damaged or worn right front wheel speed sensor
- Damaged, dirty, or broken teeth on the right front tone ring (exciter ring)
- Corroded, shorted, or open wiring or connector for the right front sensor
- Incorrect air gap between the sensor and tone ring
- Faulty ABS control module
- Electromagnetic interference in the sensor circuit
3. Symptoms You Will Notice
- ABS warning light illuminated
- Traction control or stability control warning lights on
- ABS system may not function properly, potentially causing longer stopping distances on slippery surfaces
4. Step-by-Step Diagnosis
Scan for additional ABS codes and record freeze frame data
Visually inspect the right front wheel speed sensor, wiring, and connector for damage, corrosion, or loose connections
Check the tone ring for damage, debris, or missing teeth
Measure sensor resistance and compare to specifications; test for AC voltage output while spinning the wheel
Verify the air gap between sensor and tone ring is within spec
If all else is normal, suspect a faulty ABS module and perform further module testing
5. Frequently Asked Questions
Is it safe to drive?▼
Driving with this code is not recommended because the ABS system may not function properly, increasing the risk of wheel lockup during hard braking, especially on wet or slippery roads. Have the issue diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on the cause. A new wheel speed sensor costs $30–$100, plus 1–2 hours of labor. If the tone ring or ABS module needs replacement, costs can be higher.