C0050 on 2007-2014 GMC Yukon: Right Rear Wheel Speed Sensor Fault, Causes and Fixes

What's Unique About the 2007-2014 GMC Yukon

The 2007-2014 GMC Yukon and its GMT900 platform mates (Tahoe, Suburban, Escalade) use a distinct setup for their rear wheel speed sensors. Unlike the front sensors, which are integrated into the wheel hub assembly, the rear sensors are separate, bolt-on components. This makes them much easier and cheaper to replace individually without needing to change the entire wheel hub. This design makes a failed sensor or its wiring the most probable cause for C0050, rather than a hub-related issue, although debris on the hub's magnetic ring can still be a factor.

Symptoms You May Notice

• ABS warning light is on
• StabiliTrak / Traction Control warning light is on
• "Service StabiliTrak" or "Service Traction Control" message on the driver information center
• Unwanted ABS activation (grinding or pulsing brake pedal) at low speeds
• Brake warning light may be on
• Cruise control is disabled
• Service Trailer Brake message on the Driver Information Center
• Hard steering or "Service Steering" messages

Most Likely Causes

1. Failed Right Rear Wheel Speed Sensor 🔴 High Probability → Shop ABS Wheel Speed Sensor The sensor is exposed to the elements under the vehicle, and internal electronics can fail over time due to heat cycles and vibration. It's a very common failure point on this platform, often confirmed by owners on forums. 🎬 Watch: Step-by-step guide to replacing the rear wheel speed sensor.
   How to confirm: Use a scan tool to monitor live data; the right rear wheel speed should read 0 mph or be erratic while the other wheels show correct speed. The sensor can also be tested with a multimeter for correct resistance; an open circuit (OL) or a short (near zero ohms) indicates a bad sensor. A known good sensor for this platform should have a specific resistance value, which can be compared against the suspect one. In one documented case, a technician used a heat gun on the sensor while monitoring data to confirm it would fail when hot.
   Typical fix: Replace the right rear wheel speed sensor. The sensor is held by a single T30 Torx bolt and is connected via a wiring harness. Owners on forums confirm this is often a straightforward DIY repair.
   Est. part cost: $25-$60
2. Damaged Wiring or Connector 🟡 Medium Probability The wiring harness runs along the frame and axle, where it's susceptible to damage from road debris, chafing against the frame or fuel tank, and corrosion, especially at the connector plug. Manufacturer service bulletins, such as TSB Bulletin #PIT5427B, suggest technicians inspect the X411 connector for damage or corrosion when C0050 is present alongside steering or suspension codes.
   How to confirm: Visually inspect the entire length of the harness from the sensor to where it enters the main loom. Check for breaks, chafing, or green corrosion inside the connector pins. A multimeter can be used to check for continuity from the EBCM connector to the sensor connector to rule out a break in the wire.
   Typical fix: Repair the damaged section of wire with solder and heat shrink, or replace the pigtail connector if it's corroded. Ensure the harness is properly secured away from moving parts or sharp edges.
   Est. part cost: $10-$30
3. Debris on Wheel Hub Magnetic Encoder Ring ⚪ Low Probability The magnetic encoder ring on the inboard side of the wheel hub can attract ferrous metallic debris ('fuzz') from brake dust and road grime. This disrupts the signal that the sensor reads. This is a well-documented issue across many GM platforms.
   How to confirm: After removing the wheel speed sensor, use a light and a small mirror to visually inspect the magnetic ring on the hub. Look for a build-up of metallic shavings or dirt.
   Typical fix: Clean the debris from the magnetic ring using a non-magnetic tool (like a plastic pick or nylon brush) and compressed air. Do not use a magnet. This procedure is outlined in GM TSB PIC5428G.
   Est. part cost: $0

Rare But Worth Checking

• Failed Electronic Brake Control Module (EBCM): → Shop ABS Control Module This is the least likely cause. The module itself can fail, but this should only be considered after the sensor, wiring, and hub have all been confirmed to be in good condition. A manufacturer service bulletin, TSB Bulletin #PIT5499B, notes that technicians should inspect the EBCM connector specifically for water intrusion or corrosion when codes like C0050 are stored.
• Low or Failing Battery: While not a direct cause of a C0050 code, a weak or failing battery can cause a host of random electronic issues on these trucks, including spurious "Service StabiliTrak" messages. However, if the C0050 code is consistently present, the issue is almost certainly within the sensor circuit itself.

Diagnosis Steps

1. Connect an ABS-capable scan tool and confirm the presence of code C0050. Check for any other related codes.
2. Use the scan tool to view live data. Drive the vehicle slowly (or spin the wheel with the vehicle raised) and observe the speed readings from all four wheels. Confirm that the right rear sensor is reading incorrectly (e.g., 0 mph or erratic) compared to the others.
3. Safely lift and support the rear of the vehicle. Visually inspect the wiring harness for the right rear sensor. Look for obvious signs of damage, such as chafing, breaks, or corrosion at the connector. Pay close attention to where the harness runs over the frame and near the fuel tank.
4. Disconnect the sensor. Use a T30 Torx bit to remove the single bolt holding the sensor in place. Gently twist and pull the sensor out of the axle housing. It may be seized; penetrating oil and patience may be required.
5. Inspect the magnetic encoder ring on the wheel hub through the sensor mounting hole. Check for metallic debris and clean as needed with a non-metallic brush and compressed air, as per TSB PIC5428G.
6. If the ring is clean, test the old sensor and wiring. Using a multimeter, check the resistance across the two pins of the sensor. An open circuit (OL) or a short (near zero ohms) indicates a bad sensor. Check for 12V power and a good ground at the harness connector with the key on. Wiggle the harness along its length while monitoring for changes in continuity or voltage to find intermittent breaks.
7. If the sensor and wiring appear good, but the problem persists, the issue may be a rare fault within the EBCM, which requires further professional diagnosis.

Parts You'll Likely Need

• Rear Wheel Speed Sensor (OEM #20938121) — This is the most common failure point for a C0050 code on this vehicle. The sensor is a relatively inexpensive and simple part to replace. This part number is used for both left and right rear positions. It supersedes older part numbers 10384745, 15872664, and 20763148.
  Trusted brands: ACDelco (GM Original Equipment), Delphi, Bosch, Standard Motor Products (SMP) / Intermotor (Part# ALS1466), Duralast (Part# SU9446)
  OEM price range: $45-$70
  Aftermarket price range: $25-$50

Related Codes That Often Appear With This One

• C0045 — This is the code for the Left Rear Wheel Speed Sensor. Seeing both codes together could point to a systemic issue like a damaged rear wiring harness affecting both sides, or similar debris buildup on both rear hubs.
• U0415 — This code means 'Invalid Data Received From Electronic Brake Control Module'. It can be set by other modules (like Power Steering Control) as a normal reaction when a wheel speed signal is lost, sometimes causing a 'Service Steering' message and heavier steering feel at low speeds.

Technical Service Bulletins (TSBs) & Recalls

• PIC5428G: Addresses ABS/StabiliTrak lights with codes C0035-C0050 caused by ferrous debris on the wheel bearing magnetic encoder ring. It applies to a wide range of GM vehicles, including the 2007-2014 truck and SUV platform. The bulletin advises cleaning the ring before replacing any parts.
• TSB Bulletin #PIT5427B: Notes that C0050 may be stored alongside codes for hard steering or suspension control; it recommends inspecting the X411 connector for damage or corrosion.
• TSB Bulletin #PIT5499B: Relates C0050 to symptoms like a Service Trailer Brake message and advises inspecting the Electronic Brake Control Module connector for water intrusion.

Platform-Specific Known Issues

• Wiring Harness Chafe Point: On some GM trucks of this era, the rear wheel speed sensor harness has been found to chafe on the frame rail, particularly in the area above the fuel tank. This can cause an intermittent short or open in the circuit that is difficult to see without removing the harness from its clips and inspecting it closely.

Mechanic-Grade Diagnostic Values

• Wheel Speed Sensor Resistance (Passive Sensor) — expected: 800 - 1,300 Ohms (typical). A known good new sensor may read around 1040-1100 Ohms.. Failure: An open circuit (OL) or a reading significantly outside the expected range indicates a failed sensor. Comparing the resistance to the sensor on the opposite side is a good diagnostic check.
• Wheel Speed Sensor AC Voltage Output (Passive Sensor) — expected: At least 100-200 mV AC when spinning the wheel by hand (approx. 1 revolution per 2 seconds).. Failure: Little to no AC voltage produced while the wheel is spinning points to a dead sensor.
• Voltage at Harness Connector (Vehicle Side) — expected: Approximately 12V (battery voltage) on the power supply pin and less than 1 Ohm to ground on the ground pin, with the key on.. Failure: No voltage at the power supply pin indicates a problem upstream in the wiring or with the EBCM itself.

Hidden / Shadow Codes Worth Checking

• C0050 00 / C0050 05: Indicates a general circuit malfunction, such as an open wire, short to ground, or high resistance. (see via Professional scan tools like the GM Tech2 or GDS2 that can read GM-specific symptom bytes.)
• C0050 0F: Signal Erratic. The signal is inconsistent or drops out. This strongly suggests a mechanical issue like debris on the encoder ring, a loose sensor, or a cracked ring. (see via Professional scan tools like the GM Tech2 or GDS2.)
• C0050 18: Low Signal Amplitude. The signal from the sensor is present but weak. This can be caused by a large air gap between the sensor and ring, a failing sensor, or severe debris buildup. (see via Professional scan tools like the GM Tech2 or GDS2.)
• C0050 5A: Signal Plausibility Failure. The signal is present but illogical when compared to other vehicle sensors (e.g., right rear wheel reads 5 mph while others read 50 mph). This often points to a damaged/cracked encoder ring or an intermittent wiring fault. (see via Professional scan tools like the GM Tech2 or GDS2.)

Scan Tool Commands That Help

• GM Tech2 / GDS2 or equivalent: Live Data > Wheel Speed Sensor Data — This is the primary diagnostic step. By observing the speed readings from all four wheels simultaneously while driving, a technician can instantly confirm if the right rear sensor is the one providing no signal, an erratic signal, or a signal that doesn't match the others.
• GM Tech2 / GDS2 or equivalent: Clear DTCs — After the repair (sensor replacement, wiring repair, or cleaning the hub ring) is complete, this function must be used to clear the C0050 code from the EBCM's memory. The ABS and StabiliTrak warning lights will remain on until the code is cleared and a test drive confirms the fix.

Wiring & Ground Locations

• G110 (EBCM Ground) — On the frame rail, located beneath the driver's side door. It can be identified as a heavy (12-gauge) wire.. A poor or corroded EBCM ground can cause a variety of ABS-related fault codes, including C0050, and loss of communication with the module. GM issued a TSB (04-05-25-002) regarding this specific ground, noting that a poor connection was causing unnecessary EBCM replacements. Cleaning this ground point is a critical step if multiple, seemingly unrelated ABS codes are present.
• EBCM Connector (X1) — On the Electronic Brake Control Module, located on the inside of the frame rail under the driver's side of the vehicle.. The Right Rear Wheel Speed Sensor circuit wires terminate at the EBCM connector. For a 2017 model (similar wiring), these are pins 3 and 4. Testing for continuity, shorts, and voltage must be done between the sensor connector and these specific pins at the EBCM to isolate a wiring fault from a sensor or module fault.

Real Owner Repair Stories

• Mitchell1 SureTrack Community Fix (2014 Chevrolet Tahoe LTZ 5.3L) — ABS light was on.
  ❌ Tried (didn't work) Cleared codes (code returned immediately)., Inspected wiring harness and connector (no visible faults found).
  ✅ What actually fixed it A lab scope showed no signal from the sensor. Testing at the EBCM connector revealed no 12-volt supply was being sent to the sensor. The technician replaced both the failed EBCM and the right rear ABS wheel speed sensor to resolve the issue.
• YouTube channel "Just Call Me" Ben (2008 GMC Sierra) — Intermittent traction control and ABS warning lights.
  ❌ Tried (didn't work) Initially suspected brake light switch based on other common fixes.
  ✅ What actually fixed it An ABS-capable scanner pulled code C0050. The technician tested the known-good left rear sensor with a multimeter and got no reading (indicating a passive sensor working correctly). Testing the right rear sensor showed resistance, indicating it was faulty. Replacing the right rear wheel speed sensor (GM Part #20938121) and clearing the code fixed the problem.
• YouTube channel "Diagnostic Derreck" (2007 GMC Sierra 1500 4x4) — ABS light comes on randomly.
  ❌ Tried (didn't work) Spinning the wheel on the hoist with key-on-engine-off produced no signal from either rear wheel, causing initial confusion.
  ✅ What actually fixed it The technician discovered that on this truck, the engine had to be running and the transmission in gear for the rear sensors to report speed. While monitoring live data, applying heat from a heat gun to the right rear sensor caused its signal to drop to zero. This confirmed a temperature-related internal failure of the sensor. Replacing the sensor fixed the issue.

OEM Part Supersession History

• 10384745, 15872664, 20763148 → 20938121 — Standard part evolution and consolidation by GM.
  Heads up: Some sources list part number 20938122 for this application. Always verify the correct part number for your specific vehicle's VIN with the dealer or a reliable parts catalog, as minor variations can exist.

Diagnostic Flowchart

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For this repair, using a used part is generally not recommended for the sensor itself due to its low cost new and its nature as a wear-prone electronic component. However, if a wiring issue is traced to the main body harness far from the sensor, sourcing a used harness pigtail or a section of harness from a reputable salvage yard could be a cost-effective solution, provided the donor vehicle is from a dry climate and has no signs of corrosion.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a wiring harness section: check for supple, uncracked insulation.
• Ensure there are no signs of previous, improper repairs (e.g., butt connectors, electrical tape).
• Inspect connector pins for any hint of green or white corrosion.
• Confirm the donor vehicle is from a non-salt-belt region if possible.

Aftermarket brands forum-validated for this vehicle:

• ACDelco (GM Original Equipment)
• Delphi
• Standard Motor Products (SMP)
• Bosch

Brands owners have reported issues with on this vehicle:

• Unknown, no-name brands from online marketplaces should be avoided. Forum discussions frequently highlight that ultra-cheap sensors may fail prematurely or be dead-on-arrival, making the small initial savings not worth the repeated labor.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• C0045 — Left Rear Wheel Speed Sensor Circuit. This is the direct companion code for the opposite side of the vehicle. Owners often report having C0045 and C0050 together or sequentially, and they share identical causes and repair procedures.
• C0035 — Left Front Wheel Speed Sensor Circuit. This code is covered by the same GM TSB (PIC5428G), indicating it can be caused by the same issue of ferrous debris on the wheel hub's magnetic encoder ring.
• C0040 — Right Front Wheel Speed Sensor Circuit. Like C0035, this code is also included in TSB PIC5428G and can be triggered by debris on the magnetic encoder ring, a shared potential cause with C0050.
• C0051 — Right Rear Wheel Speed Sensor Circuit Range/Performance. While C0050 indicates a general circuit fault, a range/performance code for the same sensor points to an intermittent or noisy signal, often caused by a failing sensor, wiring chafe, or debris on the encoder ring.

Frequently Asked Questions