You just pulled a C0155 on your scanner and you want to know what it really means and how to fix it without wasting time or money. C0155 is a chassis fault stored by the ABS/traction control ECU or related module when a wheel-speed or steering/angle input is missing, implausible, or out of expected voltage range. The exact label varies by make, so you’ll want to read Mode $06 data and live-stream the sensor values. In many cases the repair is wiring or sensor-level and can be diagnosed with basic tools and an OBD-II scanner with ABS capability.
What Does C0155 Mean?
C0155 is a chassis DTC flagged by the ABS, traction control, or stability control module. It indicates a fault in a wheel speed, yaw, or steering angle sensor circuit — typically a missing signal, short to ground/power, or an out-of-range voltage.
The exact description depends on the manufacturer. On some cars it refers to a specific wheel sensor circuit; on others it can indicate a steering angle or yaw rate input issue. Always check the OEM freeze-frame and Mode $06 details to narrow the source before replacing parts.
Quick Reference
- System: ABS / Traction / Stability control
- Main symptom: ABS/traction warning light
- Common fixes: sensor cleaning/replacement, connector/wiring repair
- Tools needed: OBD-II scanner with ABS, multimeter, jack stands
Real-World Example / Field Notes
I saw a C0155 after a customer hit a deep pothole. The ABS and traction lights came on immediately. Visual inspection showed a torn wheel speed sensor lead with exposed wire corroded at the connector. After repairing the connector, clearing codes, and test driving, the code didn’t return. In another case the code was caused by interior steering column water intrusion that degraded the steering angle sensor connector — a less common but important failure mode to consider.
Symptoms of C0155
- ABS warning light illuminated on the dash
- Traction control light or ESP/VSC warning
- Pulsating brakes or inconsistent ABS activation during stops
- Uneven braking or pull to one side under braking
- Fault code stored in ABS/stability module, visible in Mode $06
- Reduced stability or disabled traction control in low-traction conditions
Common Causes of C0155
Most Common Causes
- Damaged wheel speed sensor (corrosion, broken tip, contaminated tone ring)
- Frayed or corroded sensor wiring and connectors (water intrusion)
- Loose or damaged tone ring/magnetic ring on the hub or axle
- Intermittent connector contact from bent pins or debris
Less Common Causes
- Faulty ABS/traction control ECU or internal module failure
- Bad ground or reference voltage from the module
- Steering angle or yaw sensor failure (depending on OEM definition of C0155)
- Software calibration mismatch after suspension or sensor replacement
Diagnosis: Step-by-Step Guide
Tools: OBD-II scanner with ABS capability, digital multimeter, oscilloscope (helpful), jack and stands, basic hand tools, contact cleaner, dielectric grease, wiring repair kit.
- Scan and record codes; read freeze-frame and Mode $06 data to identify the affected circuit or sensor.
- Perform a visual inspection of the suspect wheel hub, tone ring, sensor head, and wiring harness for damage or contamination.
- Raise and safely support the vehicle; spin the wheel while watching live sensor data on your scanner to see if the sensor produces a clean waveform.
- Measure sensor resistance with a multimeter and compare to OEM spec; a short or open indicates a bad sensor.
- Check reference voltage and ground at the sensor connector with the key on. Typical systems have a 5V or switched reference—verify presence and stability.
- Wiggle the harness and connector while monitoring live data to locate intermittent faults from broken wires inside the jacket.
- If available, use an oscilloscope to inspect the signal waveform for missing or noisy pulses from the tone ring.
- Swap a suspected sensor with the opposite wheel (if the vehicle architecture allows) to see if the code follows the sensor.
- Repair or replace the failed sensor/wiring, clean connectors, apply dielectric grease, and secure the harness away from heat and moving parts.
- Clear codes, perform any required relearn or calibration (steering angle sensors often require a basic steer-angle reset), and road-test while monitoring live data.
Professional tip: Always compare the suspect sensor’s live output to the same-side or opposite-side sensor. A visual waveform comparison catches marginal sensors that resistance tests miss.
Possible Fixes & Repair Costs
Typical repair costs vary widely: simple connector cleaning and wiring repair can run $50–$200 in parts and labor. Replacing a wheel speed sensor typically costs $80–$350 per sensor, depending on OEM vs aftermarket and labor. If the ABS module or wiring harness needs replacement or programming, expect $400–$1,500 or more. Factors that affect cost include part price, labor rates, access difficulty, and whether calibration or reprogramming is required.
Can I Still Drive With C0155?
You can usually drive a short distance with C0155, but ABS or traction control may be disabled. That increases stopping distances and reduces stability assistance in low-traction situations. Avoid high-speed travel and wet or icy roads; drive to a repair shop or tow if safety is a concern.
What Happens If You Ignore C0155?
If you ignore C0155 the ABS and stability systems may remain offline, exposing you to higher risk in emergency braking or slippery conditions. Continued driving can also lead to further sensor or wiring damage and cause related components to fail or wear unevenly.
Related Codes
- C0194 – Chassis Wheel Speed Signal Plausibility
- C0193 – Traction Control Torque Request Signal Range/Performance
- C0192 – Chassis Wheel Speed Signal Plausibility
- C0191 – Traction Control Torque Request Signal Low
- C0190 – Traction Control Torque Request Signal
- C0189 – Brake Wheel Speed Signal Plausibility
- C0188 – Stop Lamp Switch Circuit Range/Performance
- C0187 – Brake Wheel Speed Signal Plausibility
- C0186 – Chassis Wheel Speed Sensor Circuit Fault
- C0185 – Chassis Wheel Speed Signal Plausibility
Key Takeaways
C0155 flags a chassis-level signal problem in the ABS/stability system. Most failures are sensors or wiring, which you can diagnose with a scanner, multimeter, and visual inspection. Clear codes only after a verified fix. Don’t ignore the warning lights — they protect braking and stability functions and keep you safe on the road.
Vehicles Commonly Affected by C0155
This code appears on many makes: common reports come from Toyota, Honda, Ford, GM, BMW, and VW vehicles. Trucks, SUVs, and older cars that see a lot of road salt or off-road use are more susceptible because wheel sensors and harnesses are exposed to damage and corrosion.
FAQ
Can I clear C0155 with a cheap OBD-II scanner?
Basic scanners will clear generic codes, but ABS/chassis codes like C0155 often require an ABS-capable tool to read freeze-frame and Mode $06. Clearing without diagnosing can cause the code to return immediately.
Is C0155 always a bad sensor?
No. C0155 can be caused by wiring, connectors, tone ring damage, poor ground, or module issues. Confirm with live data and basic electrical tests before replacing the sensor.
Can I replace the wheel speed sensor myself?
Yes, if you’re comfortable with basic hand tools, safely lifting the vehicle, and reversing the removal procedure. Follow torque specs and don’t forget to clean the connector and secure the harness. Some cars require a brief calibration after replacement.
How long will a wheel speed sensor last?
Wheel speed sensors often last many years, but exposure to road debris, salt, or impact shortens life. Typical lifespan is 50,000–100,000 miles, but failures are common on older, rusted hubs or after impacts.
Will replacing the ABS module fix C0155?
Only if diagnostics point to an internal module failure. Replacing the module without confirming will waste money. Always verify sensor signals, wiring, and connector integrity first. If module replacement is needed, budget for programming or calibration.