C0050 on 2009-2012 Chevrolet Colorado: Right Rear Wheel Speed Sensor Causes & Fixes

What's Unique About the 2009-2012 Chevrolet COLORADO

The first-generation Chevrolet Colorado (a GM GMT355 platform truck) uses a wheel speed sensor that is integrated with the wheel hub and bearing assembly. A magnetic encoder ring on the inboard side of this hub is what the sensor reads. This design is notoriously susceptible to collecting a paste-like mixture of metallic dust and road grime, which disrupts the sensor's reading. This specific failure mode is so common that GM has issued multiple Technical Service Bulletins, including PIC5428G, advising technicians to inspect and clean this ring 🎬 Watch: How to clean the magnetic ring before replacing parts. before replacing parts. In some cases, the magnetic ring itself can crack or delaminate from the hub, requiring replacement.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• ABS warning light is on
• StabiliTrak or Traction Control (TC) warning light is on
• "Service StabiliTrak" or "Service Traction Control" message in the driver information center
• ABS system does not activate during hard braking (wheels may lock up)
• Possible clicking or grinding noises from the ABS modulator at low speeds, as noted in TSBs.
• Flashing Traction Control light at low speeds.

Most Likely Causes

1. Debris on Wheel Hub Magnetic Encoder Ring 🔴 High Probability The hub's design features an exposed magnetic encoder ring that attracts ferrous metallic debris from brake wear and road grime. This is the exact issue described in GM TSB #PIC5428G and its successors.
   How to confirm: Visually inspect the inboard side of the right rear wheel hub assembly. The magnetic ring will be covered in a dark, metallic paste. A scan tool showing symptom byte '18' or '5A' strongly suggests this issue.
   Typical fix: Gently clean the debris from the encoder ring with a soft, non-magnetic brush (like a nylon bristle brush) and brake cleaner. If the seal is damaged or the problem returns, the hub assembly must be replaced. Some owners report cleaning is only a temporary fix.
   Est. part cost: $0 (if cleaning works)
2. Failed Wheel Hub and Bearing Assembly 🔴 High Probability The wheel speed sensor is integrated into the hub assembly. The internal sensor can fail, or the magnetic encoder ring can crack or delaminate from age and heat cycles, causing a total loss of signal. Bearing wear can also cause excessive play, leading to an erratic signal. This is the most common permanent repair reported by owners.
   How to confirm: After cleaning the ring, if the code persists, use a scan tool to monitor live data; the right rear wheel speed will read 0 or be erratic compared to the others. Also, check for physical play in the wheel bearing. A visual inspection may reveal a cracked or missing section of the brown magnetic ring.
   Typical fix: Replace the entire right rear wheel hub and bearing assembly. Ensure you purchase the correct part for 2WD vs. 4WD/Z71 models.
   Est. part cost: $80-$250
3. Damaged Wiring or Connector 🟡 Medium Probability The wiring harness runs along the frame and suspension to the wheel, making it vulnerable to chafing, corrosion, and impact damage from road debris. Owners have noted that wires can chafe and break internally near the frame or suspension mounting points, even if the outer insulation looks intact.
   How to confirm: Visually inspect the harness from the wheel hub connector to the main chassis harness. Check for broken wires, corrosion in the connector pins, or chafing. A multimeter can be used to test for continuity and shorts to ground between the EBCM connector and the wheel sensor connector.
   Typical fix: Repair the damaged section of wiring or replace the pigtail connector. Ensure the repair is sealed against moisture.
   Est. part cost: $15-$50

Rare But Worth Checking

• Faulty Electronic Brake Control Module (EBCM): This is a rare cause and should only be considered after the hub, sensor, and wiring have been definitively ruled out. A failed EBCM is an expensive repair and misdiagnosis is common.

Diagnosis Steps

1. Connect an ABS-capable scan tool and confirm C0050 is the active code. Note any symptom bytes like '18' (Signal Amplitude Less Than Minimum), '5A' (Signal Not Plausible), or '0F' (Erratic Signal) if your scanner can read them, as they provide more specific information pointing towards a mechanical/debris issue at the hub.
2. Safely raise and support the rear of the vehicle. Spin the right rear wheel by hand and use the scan tool to view live data. The speed should register smoothly and match the other wheels. If it reads 0 mph or jumps erratically, the problem is at that corner.
3. Remove the right rear wheel. Visually inspect the wheel speed sensor wiring harness for any obvious signs of damage, chafing against the frame or suspension components, or corrosion at the connector.
4. Remove the brake caliper and rotor to gain access to the wheel hub assembly.
5. Inspect the inboard side of the hub for the brown magnetic encoder ring. Check for a build-up of dark, metallic paste or any visible cracks or missing chunks from the ring itself.
6. If debris is present, gently clean the ring with a soft nylon brush and brake cleaner. Do not use magnetic tools or compressed air, as they can damage the encoder.
7. If the ring was clean, is physically damaged, or cleaning does not resolve the issue, the hub assembly itself is the most likely culprit. Replacing the right rear wheel hub assembly is the next step.
8. If a new hub assembly does not fix the code, perform a continuity and resistance test on the wiring harness between the hub connector and the EBCM to rule out an open or shorted wire.
9. Only if all other components test good should the EBCM be considered as the potential cause.

Parts You'll Likely Need

• Right Rear Wheel Hub and Bearing Assembly (OEM #GM 15282123 (Verify for 4WD/Z71 models)) — This assembly contains the integrated wheel speed sensor and the magnetic encoder ring, which are the two most common failure points for a C0050 code on this vehicle. The sensor and ring are not serviced separately.
  Trusted brands: ACDelco (FW420 is a common p/n), Timken (HA590246 is a common p/n), MOOG, Duralast
  OEM price range: $180-$250
  Aftermarket price range: $80-$160

Related Codes That Often Appear With This One

• C0035 — Indicates a fault with the Left Front wheel speed sensor. Seeing multiple wheel speed codes together could point to a systemic issue like a failing EBCM or widespread wiring problems. The TSB #PIC5428G covers the entire range from C0035 to C0050.
• C0040 — Indicates a fault with the Right Front wheel speed sensor. The TSB #PIC5428G covers the entire range from C0035 to C0050.
• C0045 — Indicates a fault with the Left Rear wheel speed sensor. Seeing it with C0050 could suggest a common problem affecting the rear axle wiring or similar debris buildup on both rear hubs.

Technical Service Bulletins (TSBs) & Recalls

• PIC5428G: EBCM Wheel Speed Sensor Diagnostic Aid for ABS Message, Service Traction Message, Service Stabilitrak Message. This TSB confirms that debris on the magnetic encoder ring is a known cause for codes C0035-C0050.
• 17-NA-047: This bulletin supersedes PIC5428G and contains the same core diagnostic information regarding debris on the magnetic encoder, applying to a wide range of GM vehicles including the Colorado.

Platform-Specific Known Issues

• GM Technical Service Bulletin PIC5428G (and its successors like 17-NA-047) specifically addresses codes C0035-C0050 on the 2009-2012 Colorado. It identifies metallic debris on the wheel bearing's magnetic encoder ring as a primary cause for StabiliTrak/ABS warnings and recommends cleaning the ring as a first step before any parts replacement.

Mechanic-Grade Diagnostic Values

• Wheel Speed Sensor AC Voltage Output — expected: Greater than 100mV (0.1V AC) when spinning the wheel by hand.. Failure: No AC voltage is generated, or the voltage is erratic and does not increase smoothly with wheel speed.
• Wheel Speed Sensor Resistance — expected: Typically 800-1700 Ohms, but the most important check is that the resistance is not infinite (open circuit) and is very close to the reading from the opposing (left rear) sensor.. Failure: An open circuit (OL) reading on the multimeter, or a resistance value that is drastically different from the sensor on the other side of the axle.

Hidden / Shadow Codes Worth Checking

• C0050 00: Indicates a general circuit malfunction, such as an open wire, a short to ground, or high resistance. (see via Requires an ABS-capable scan tool (like a GM Tech2/GDS2) that can read manufacturer-specific symptom bytes.)
• C0050 0F: Indicates the sensor is producing an erratic signal. This often points to a damaged or contaminated magnetic encoder ring on the hub. (see via Requires an ABS-capable scan tool that can read GM-specific symptom bytes.)
• C0050 18: Indicates the signal amplitude is too low (a weak signal). This can be caused by a failing sensor, an excessive air gap, metallic debris, or a damaged magnetic ring. (see via Requires an ABS-capable scan tool that can read GM-specific symptom bytes.)
• C0050 5A: Indicates the signal is not plausible, meaning it is inconsistent with the signals from the other wheel speed sensors. (see via Requires an ABS-capable scan tool that can read GM-specific symptom bytes.)

Wiring & Ground Locations

• EBCM (Electronic Brake Control Module) — Located on the inner left (driver's side) frame rail, next to the transmission.. This module receives the signal from the right rear wheel speed sensor. All circuit testing ultimately leads back to the EBCM connector.
• EBCM Connector Pins 3 & 4 — On the main electrical connector for the EBCM. Pin 3 is the signal circuit, and Pin 4 is the low reference (ground) circuit for the right rear wheel speed sensor.. These are the specific pins to test at the module for continuity, shorts, or voltage when diagnosing a wiring fault between the sensor and the EBCM.
• Ground Splice Pack SP105 — Located in the engine compartment on the driver's side, near the battery.. This splice pack provides a ground path for the Electronic Brake Control Module (EBCM). Corrosion or a poor connection here can cause various ABS faults.
• Ground Splice Pack SP106 — Located in the engine compartment on the passenger's side, behind the engine airbox.. This is another ground splice pack that provides a ground for the EBCM. A fault here can also lead to ABS system issues.
• Yaw Rate / Lateral Accelerometer Sensor — Located under the driver's seat, bolted to the floor.. While not a direct cause of C0050, this sensor is a key input for the StabiliTrak system. A fault here can cause related StabiliTrak messages, and its wiring communicates with the EBCM.

Real Owner Repair Stories

• YouTube channel 'Phillip Bailey' (2017 GM Truck (similar platform/system)) — ABS and TCS lights on, active code C0050 for right rear wheel speed sensor circuit failure.
  ❌ Tried (didn't work) Initial visual inspection showed no obvious breaks in the harness.
  ✅ What actually fixed it A graphing ohmmeter revealed a high resistance fluctuation. A very small, hard-to-see pinhole in the wire insulation right near the sensor connector had allowed corrosion to form internally. Repairing this single compromised wire and sealing the harness resolved the code.