C0050 on 2012-2017 Buick Verano: Right Rear Wheel Speed Sensor Fault Guide

What's Unique About the 2012-2017 Buick VERANO

The Buick Verano, and its platform-mates like the Chevy Cruze, integrate the wheel speed sensor's magnetic encoder ring directly into the wheel hub and bearing assembly. This design makes the encoder highly susceptible to contamination from ferrous metallic debris from normal brake wear and road grime. This specific issue is well-documented in GM's Technical Service Bulletin PIC5428G (and its successor 17-NA-047), often leading to a fix that involves cleaning the hub rather than immediate part 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
• Service StabiliTrak / Traction Control warning light is on
• Service Brake Assist message may appear in the driver information center
• ABS may not activate during hard braking
• A brief grinding or ratchet noise may be heard at low speeds as the system performs self-checks or falsely activates.
• Power steering may feel heavier at low speeds (if code U0415 is also present).

Most Likely Causes

1. Debris on Wheel Bearing Magnetic Encoder Ring 🔴 High Probability The open design of the magnetic encoder on the inboard side of the hub assembly makes it act like a magnet, attracting ferrous metallic debris from brake wear and road grime. This is the primary issue addressed by GM TSBs.
   How to confirm: Visually inspect the brown magnetic ring on the inboard side of the right rear wheel hub for any metallic shavings or a paste-like buildup. This may require removing the hub assembly for a clear view, though sometimes it can be seen by removing just the wheel and looking from behind.
   Typical fix: Thoroughly clean the debris from the magnetic encoder ring. TSB PIC5428G recommends using a dry, soft nylon bristle brush first, and if debris remains, washing with mild soap and water. It is critical *not* to use a magnet or harsh solvents for cleaning, as this can damage the encoder. If the code returns, the hub is likely damaged and needs replacement.
   Est. part cost: $0
2. Failed Wheel Speed Sensor / Hub Bearing Assembly 🟡 Medium Probability The wheel speed sensor is integrated into the hub assembly and is not sold separately. Over time, internal failure of the sensor electronics or physical damage (cracks, chips) to the magnetic encoder ring can occur. Intermittent failure when hot is also a possibility.
   How to confirm: Using a scan tool, monitor the live data for the right rear wheel speed while driving or spinning the wheel by hand. If the signal drops out, is erratic, or doesn't match the other wheels, the sensor/hub assembly is faulty. A Reddit user confirmed their C0050-18 was fixed by replacing the hub after finding the tone ring was damaged.
   Typical fix: Replace the entire right rear wheel hub and bearing assembly. This is the definitive fix if cleaning fails or the bearing itself is noisy or loose.
   Est. part cost: $80-$250
3. Damaged Wiring or Connector ⚪ Low Probability The wiring harness leading to the wheel is exposed to the elements, road debris, and suspension movement, which can cause chafing, corrosion in the connector, or breaks over time. Water intrusion, especially in humid or snowy climates, can cause intermittent issues.
   How to confirm: Visually inspect the wiring harness from the EBCM to the right rear wheel for any signs of damage, corrosion in the connector, or loose pins. A multimeter can be used to check for continuity and shorts to ground/power between the EBCM connector and the wheel speed 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

• Failed Electronic Brake Control Module (EBCM): This is the least likely cause. An EBCM failure usually triggers multiple wheel speed sensor codes or communication codes, not just a single one. Exhaust all other possibilities before considering EBCM replacement.

Diagnosis Steps

1. Connect an OBD-II scanner capable of reading ABS codes to confirm C0050 is present and note any symptom bytes (e.g., 0F, 18, 5A). Symptom byte '18' points to a low or erratic signal, while '5A' indicates the signal is not plausible compared to other wheels.
2. Clear the codes and perform a test drive to see if the code immediately returns.
3. Use the scanner's live data function to monitor all four wheel speed sensors. Confirm that the right rear sensor provides an erratic, absent, or mismatched signal compared to the others while driving straight.
4. Raise the vehicle and perform a thorough visual inspection of the right rear wheel speed sensor wiring and connector for any obvious damage, corrosion, or looseness.
5. Remove the right rear wheel. Inspect the brown magnetic encoder ring on the inboard side of the wheel bearing for metallic debris, as described in TSB PIC5428G.
6. If debris is present, clean it off thoroughly with a soft, non-magnetic brush and/or mild soap and water, then dry completely. Reassemble and test drive.
7. If no debris is found, the encoder ring is physically damaged (cracked/chipped), or the code persists after cleaning, the wheel hub/bearing assembly is the most likely cause and should be replaced.

Parts You'll Likely Need

• Rear Wheel Hub and Bearing Assembly (OEM #ACDelco RW20-157) — This assembly contains the wheel speed sensor and the magnetic encoder ring. It is the most common fix when cleaning debris is not enough or the sensor has failed internally.
  Trusted brands: ACDelco, Timken, MOOG, SKF
  OEM price range: $180-$250
  Aftermarket price range: $80-$160

Related Codes That Often Appear With This One

• U0415 — This code for 'Invalid Data Received From EBCM' may set in the Power Steering Control Module (PSCM). The electric power steering system relies on wheel speed data for variable assist. When the C0050 fault occurs, the PSCM loses a critical data input and may default to a reduced-assistance mode as a safety measure, making steering feel heavy at low speeds.

Technical Service Bulletins (TSBs) & Recalls

• PIC5428G: Addresses ABS/StabiliTrak lights with DTCs C0035-C0050, pointing to debris on the wheel bearing's magnetic encoder ring as a likely cause.
• 17-NA-047: Supersedes PIC5428G, providing updated model year information and reinforcing the same diagnostic and cleaning procedure.

Platform-Specific Known Issues

• A GM Technical Service Bulletin (PIC5428G), later superseded by 17-NA-047, directly addresses code C0050 (with symptom bytes 18, 5A, or 0F) on the 2012-2017 Verano. It identifies metallic debris accumulating on the wheel bearing's magnetic encoder as a primary cause and recommends inspection and cleaning before parts replacement.
• The issue is so common on the Delta II platform that many owners of the Chevrolet Cruze, a direct platform mate, have documented the exact same problem and repair process online.

Mechanic-Grade Diagnostic Values

• Wheel Speed Sensor (Passive Type) Internal Resistance — expected: 800 - 1,700 Ohms (general GM spec). Failure: A reading of OL (Open Loop/infinity) or near zero Ohms indicates a failed sensor.
• Wheel Speed Sensor AC Voltage Output — expected: Greater than 100mV (0.1V) AC when spinning the wheel by hand. Voltage should increase with speed.. Failure: No AC voltage produced while the wheel is spinning indicates a dead sensor.
• Sensor Signal Wire Bias Voltage (at sensor connector, unplugged) — expected: Approximately 5V DC on one wire (bias from EBCM) and 0V on the other (ground return).. Failure: No bias voltage suggests a wiring problem or an issue with the EBCM itself, not the sensor.

Hidden / Shadow Codes Worth Checking

• C0050 06: Right Rear Wheel Speed Sensor Circuit Low Voltage/Open. This points to an open circuit, short to ground, or high resistance in the wiring. (see via A professional scan tool capable of reading GM-specific symptom bytes (e.g., Tech 2, GDS2, high-end Autel/Snap-on).)
• C0050 0F: Right Rear Wheel Speed Sensor Circuit Signal Erratic. This indicates the signal is inconsistent or jumping, often caused by debris on the encoder ring or a failing sensor. (see via A professional scan tool capable of reading GM-specific symptom bytes.)
• C0050 18: Right Rear Wheel Speed Sensor Circuit Low Signal Amplitude. The signal is present but too weak, often due to an increased air gap or internal sensor fault. (see via A professional scan tool capable of reading GM-specific symptom bytes.)
• C0050 5A: Right Rear Wheel Speed Sensor Circuit Not Plausible. The signal from this sensor does not match the signals from the other wheel speed sensors, suggesting it's reading incorrectly. (see via A professional scan tool capable of reading GM-specific symptom bytes.)

Wiring & Ground Locations

• EBCM Connector (X1) — The Electronic Brake Control Module is located on the brake pressure modulator valve, typically near the brake master cylinder in the engine bay.. This is the main connector where the wheel speed sensor signals terminate. Testing for power, ground, and signal continuity happens here.
• EBCM Connector Pins 3 & 4 — Within the main EBCM connector.. On this platform, Pin 3 (Green/Yellow wire) is the 12V supply from the EBCM to the RR sensor, and Pin 4 (Violet wire) is the signal return wire. Checking continuity and for shorts on these specific wires is a key diagnostic step.
• EBCM Ground — A primary ground point for the EBCM is located on the frame rail, directly under the driver's side door area.. A corroded or loose main ground can cause intermittent and difficult-to-diagnose ABS faults, including C0050, even if the sensor and its direct wiring are good. GM has issued bulletins on other vehicles regarding the importance of cleaning this ground.
• EBCM Harness Chafe Point — The harness branch leading to the EBCM may rub against a transmission mounting bolt or the frame/strut tower area behind the radiator surge tank.. A GM document notes that abrasion at this point can cause shorts or open circuits for various EBCM functions, potentially leading to a C0050 code. The fix involves repositioning or repairing the harness.

Real Owner Repair Stories

• YouTube channel 'Phillip Bailey' (2017 GMC Sierra (similar GM electrical architecture)) — ABS and Traction Control lights on, code C0050 active.
  ❌ Tried (didn't work) Visual inspection of the harness showed no obvious damage., The previous mechanic had already replaced the right rear wheel speed sensor, but the code remained.
  ✅ What actually fixed it Using a graphing ohmmeter, the technician found an open circuit (corrosion) inside the wiring very close to the wheel speed sensor connector. The resistance would fluctuate wildly when the wire was wiggled. Repairing the corroded section of wire and reconnecting the original sensor fixed the problem.

OEM Part Supersession History

• 13577407, 13502873 → ACDelco RW20-157 (GM Genuine Parts) — Part number consolidation and potential minor revisions.
  Heads up: The RW20-157 part is the correct OE replacement for the entire 2012-2017 Verano range.