C0133 is a chassis (ABS/traction) trouble code that usually points to a problem with a wheel speed signal, most often from the right rear wheel. When this code sets, your ABS module is telling you it’s not happy with the data it’s getting, which can affect ABS, traction control, and stability systems. You might notice warning lights on the dash, longer stopping distances on slippery roads, or odd behavior during braking. This guide walks you through what C0133 means, common causes, symptoms, and how you can diagnose and fix it.
What Does C0133 Mean?
C0133 is a chassis-related diagnostic trouble code that typically indicates a right rear wheel speed sensor circuit problem or an issue with the signal that sensor sends to the ABS control module. Depending on the manufacturer, the description may read “Right Rear Wheel Speed Sensor Circuit Malfunction” or “Wheel Speed Signal Erratic.”
Your ABS module constantly monitors wheel speed sensors to control anti-lock braking, traction control, and sometimes stability control. If the signal from one wheel becomes intermittent, out of range, or drops out completely, the module logs C0133 and usually turns on the ABS and traction warning lights.
Quick Reference
- Code: C0133
- Type: Chassis / ABS / Wheel speed sensor
- Typical Meaning: Right rear wheel speed sensor circuit issue
- Main Systems Affected: ABS, traction control, stability control
- Risk Level: Moderate – braking still works, but safety features may be reduced
Real-World Example / Field Notes
In the shop, I see C0133 most often on GM trucks, SUVs, and some sedans, but other brands are not immune. A common scenario: the driver comes in with ABS and traction lights on after driving through heavy rain or snow. Scan tool shows C0133 stored or pending. A quick visual check reveals a cracked right rear wheel speed sensor harness rubbing against the suspension arm. The wire corrodes, signal drops out over bumps, and the ABS module flags C0133. Replacing the sensor and repairing the harness clears the code and restores normal ABS operation.
Symptoms of C0133
- ABS warning light on – The ABS indicator stays lit on the dash once the fault is detected.
- Traction control light on – The TC or stability control light may illuminate or flash.
- Loss of ABS function – Under hard braking, wheels may lock instead of pulsing.
- Reduced traction control – Wheel spin on acceleration may not be controlled as usual.
- Intermittent warning lights – Lights may come and go with bumps or wet conditions.
- Unusual braking feel – You may feel pulsing or vibration at low speed, especially just before stopping.
- Possible speedometer fluctuation – On some vehicles, the speedometer may jump or drop if the system uses that sensor for vehicle speed.
Common Causes of C0133
Most Common Causes
- Failed wheel speed sensor (right rear) – Internal sensor failure, open circuit, or shorted sensor is the top cause.
- Damaged sensor wiring or connector – Broken wire, corroded terminals, or loose connector at the sensor or along the harness.
- Contaminated or cracked tone ring/reluctor – Rust buildup, missing teeth, or debris on the tone ring causing erratic readings.
- Improper wheel bearing play – Excessive play in the hub bearing can change the sensor gap and distort the signal.
- Recent brake or suspension work – Sensor wire accidentally stretched, pinched, or not fully reconnected after repairs.
Less Common Causes
- ABS module internal fault – Failed circuit inside the ABS control module misreading a good sensor signal.
- Poor ground or power supply to ABS module – Low voltage, corroded grounds, or intermittent power causing false codes.
- Water intrusion into connectors – Moisture inside harness plugs causing intermittent resistance changes.
- Incorrect tire size or mismatched tires – On sensitive systems, drastically different rolling diameters can confuse the module.
- Aftermarket electronics interference – Poorly installed alarm or remote start systems spliced into ABS-related wiring.
Diagnosis: Step-by-Step Guide
Tools you’ll want: a quality scan tool that can read ABS codes and live data, a digital multimeter, basic hand tools, jack and jack stands, and ideally a wiring diagram for your specific vehicle. A scope is helpful but not mandatory for most DIYers.
- Confirm the code and check for others
Connect a scan tool and read all stored and pending codes. Note if C0133 is present alone or with other wheel speed or ABS codes. Clear the codes and see if C0133 returns during a short test drive. - Inspect the right rear sensor and wiring
Safely lift the vehicle and remove the right rear wheel if needed. Visually inspect the wheel speed sensor, harness, and connector. Look for cuts, rubbing, broken clips, corrosion, or loose plugs. - Check for debris and rust
Inspect the tone ring or encoder (sometimes built into the hub). Look for rust buildup, missing teeth, cracks, or packed dirt/metal shavings that could interfere with sensor readings. - Wiggle test the harness
With the vehicle running and the scan tool on live data, gently move the sensor harness while watching the right rear wheel speed reading. If it drops out or spikes when you move the wire, you likely have an internal break or bad connection. - Measure sensor resistance
Disconnect the sensor and use a multimeter to measure resistance across the sensor terminals. Compare the reading to spec (service manual). Infinite resistance indicates an open; near-zero may indicate a short. - Check sensor signal (if possible)
Spin the wheel by hand while monitoring wheel speed on the scan tool. The right rear speed should match the other wheels. If your tool supports Mode $06 or ABS data, look for error counts or dropout events. - Inspect wheel bearing and play
Grab the wheel at 12 and 6 o’clock and check for excessive play. A loose hub can change the sensor gap and cause an unstable signal that triggers C0133. - Verify power/ground at ABS module (advanced)
If the sensor and wiring check out, use a wiring diagram to test continuity from the sensor to the ABS module and verify proper power and ground at the module. This step is usually best left to a pro if you’re not comfortable with electrical testing. - Recheck and road test
After any repair or adjustment, clear the codes and perform a road test including low-speed braking and some turns. Re-scan to confirm C0133 does not return.
Pro tip: Always compare the suspect wheel’s live speed data to the other wheels. A sensor that only glitches at low speed or over bumps can be hard to catch without watching live data during a test drive.
Possible Fixes & Repair Costs
Most repairs for C0133 are straightforward once you pinpoint the fault. Common fixes include:
- Replacing the right rear wheel speed sensor
- Repairing or replacing the sensor harness/connector
- Cleaning or replacing a damaged tone ring or hub assembly
- Repairing corroded grounds or power feeds to the ABS module
- In rare cases, replacing the ABS control module
Typical repair costs vary with vehicle type and labor rates. A wheel speed sensor replacement usually runs $150–$350 parts and labor. Harness repairs can be $100–$250 depending on access. A hub assembly with integrated sensor may cost $300–$600. An ABS module replacement is the most expensive, often $600–$1,200+. Factors affecting cost include OEM vs aftermarket parts, rust/corrosion level, and how difficult the sensor or hub is to access on your specific vehicle.
Can I Still Drive With C0133?
In most cases, you can still drive with C0133, but you should understand the risk. Your basic hydraulic brakes will still work, but ABS and traction control may be disabled or limited. That means in a panic stop, you’re more likely to lock up a wheel and lose steering control, especially on wet, icy, or loose surfaces. If the ABS and traction lights are on, drive cautiously, leave extra following distance, and avoid aggressive braking until the issue is repaired.
What Happens If You Ignore C0133?
If you ignore C0133, you’re essentially driving without the safety net of ABS and traction control. Over time, a damaged sensor or harness can worsen, potentially causing additional codes or even affecting other systems that share wheel speed data. You also risk failing state inspections where ABS warning lights are checked. It’s not an emergency like a no-brake situation, but it’s a safety-related issue you shouldn’t put off for long.
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
- C0133 almost always points to a right rear wheel speed sensor signal or circuit problem.
- Common causes include a bad sensor, damaged wiring, rusted tone ring, or loose wheel bearing.
- Symptoms are mainly ABS and traction lights, plus reduced anti-lock and stability functions.
- Diagnosis focuses on visual inspection, live data comparison, and basic electrical tests.
- Repairs are usually mid-range in cost and should be done soon for safety, especially in poor weather.
Vehicles Commonly Affected by C0133
C0133 is especially common on GM vehicles such as Chevrolet Silverado, Tahoe, Suburban, TrailBlazer, Malibu, and GMC Sierra and Yukon models. It also appears on some Buick, Pontiac, and Cadillac cars and SUVs using similar ABS hardware. Other manufacturers, including Toyota, Nissan, and Hyundai, may use the same or similar code for right rear wheel speed sensor issues. You’ll see it most often on trucks and SUVs that see winter road salt, off-road use, or heavy towing, where wiring and hubs are exposed to more abuse.
FAQ
Can I clear C0133 and keep driving without fixing it?
You can clear the code with a scan tool, but if the underlying problem remains, C0133 will come back, often quickly. Clearing the code doesn’t restore proper ABS or traction function; it only erases the warning until the fault is detected again.
Is C0133 always the right rear wheel speed sensor?
On most vehicles, yes, C0133 refers to the right rear wheel speed sensor circuit or signal. However, some manufacturers may label it slightly differently. It’s always smart to confirm the description in a service manual or with a professional scan tool for your specific make and model.
How do I know if it’s the sensor or the wiring causing C0133?
The best way is to use a multimeter and scan tool. If the sensor’s resistance is out of spec or open, it’s likely bad. If moving the harness causes the signal to drop out on live data, you probably have a wiring issue. Corrosion at the connector is another strong clue that wiring is the culprit.
Can a bad wheel bearing trigger C0133?
Yes. If the wheel bearing is worn and allows the hub to wobble, the gap between the sensor and tone ring can change as you drive. That can distort the signal enough for the ABS module to set C0133, even if the sensor and wiring are technically good.
How urgent is it to fix C0133?
It’s not as urgent as a brake fluid leak or total brake failure, but it is a safety concern. Without ABS and traction control, your stopping distance and stability can suffer, especially in wet or icy conditions. Plan to diagnose and repair C0133 as soon as practical rather than putting it off indefinitely.