C0055 on 2007-2011 GMC Sierra: Rear Wheel Speed Sensor Circuit Fault Explained

What's Unique About the 2007-2011 Gmc SIERRA

Unlike many vehicles with a speed sensor at each wheel, the GMT900 platform (which includes the 2007-2011 Sierra) uses a single sensor for the rear axle. This design makes diagnosis simpler but also means a single sensor or wiring failure will disable the ABS and StabiliTrak systems entirely. A very common and well-documented failure point on these trucks is the sensor's wiring harness, which is prone to rubbing through on the top of the transmission bellhousing, causing an intermittent or total loss of signal. For 4WD models, there is often a short extension pigtail harness that connects the main harness to the sensor, and this extension is a frequent culprit.

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 warning light is on
• "Service StabiliTrak" or "Service Traction Control" message on the dashboard
• Cruise control is disabled
• Harsh or erratic transmission shifting
🎬 See how a faulty sensor causes shifting and speedometer issues
• Brake light may be illuminated
• In some cases, the speedometer may be inaccurate or dead (more common on older GMT800 platform, but possible)

Most Likely Causes

1. Faulty Rear Wheel Speed Sensor (VSS) 🔴 High Probability This sensor is exposed to constant heat and vibration at the transmission/transfer case, leading to eventual electronic failure. It is a very common replacement part for this platform.
   How to confirm: Use a scan tool to monitor the 'Rear Wheel Speed' data PID while driving; if the reading is zero, erratic, or doesn't change with speed, the sensor is likely bad. A good sensor should have a resistance between 1200-2900 ohms when tested with a multimeter. Visually inspect the sensor's magnetic tip for excessive metal shavings upon removal.
   Typical fix: Replace the Vehicle Speed Sensor. It is held in by a single bolt (often 13mm or 19mm) on the transmission tail housing or transfer case.
   Est. part cost: $25-$70
2. Chafed or Damaged Wiring Harness 🔴 High Probability The VSS wiring harness is commonly routed over the top of the transmission, where it can rub against the housing or the firewall, eventually wearing through the insulation of the purple and green/yellow wires and causing a short or open circuit. This is an extremely common failure point.
   How to confirm: Visually inspect the entire length of the wiring harness from the sensor connector up and over the transmission bellhousing. Pay close attention to the area between the back of the engine and the firewall. 🎬 Watch: How to trace and replace the VSS wiring harness Check for continuity on both wires between the sensor connector and the EBCM or PCM.
   Typical fix: Repair the damaged section of wire using solder and heat shrink tubing. Ensure the repaired section is properly secured and protected from future chafing. If the damage is close to the connector, replace the connector pigtail.
   Est. part cost: $10-$40
3. Failed Electronic Brake Control Module (EBCM) ⚪ Low Probability
   How to confirm: This should only be suspected after confirming the sensor and wiring are good. Use an oscilloscope to verify that a clean square wave signal from the sensor circuit is reaching the EBCM connector. If a good signal is present but the code remains, the EBCM has likely failed internally. The speedometer will typically still work, as the VSS signal goes to other modules first.
   Typical fix: Replace the electronic (non-hydraulic) portion of the ABS module. This is typically held on by four to six Torx screws and can be replaced without opening the brake hydraulic system. The new module may require programming.
   Est. part cost: $150-$400

Rare But Worth Checking

• Internal Transfer Case/Transmission Wear: A worn output shaft bushing or bearing can allow the reluctor (tone) ring to wobble, creating an erratic signal or physically contacting and damaging the speed sensor. This was noted in TSB #PIP4966B and discussed by owners. One owner on DuramaxDiesels.com reported that a trashed rear bearing in the transfer case destroyed the extension housing bushing, which allowed the output shaft to 'wallow around,' causing the tone ring to hit the sensor. If you find a sensor is physically damaged or repeatedly fails, this may be the underlying cause.
• Software Anomaly / History Code: According to TSB #06-05-25-003, a C0055 code stored in history (not active) without any warning lights or symptoms can sometimes be set by a specific ignition key sequence (like quickly cycling from RUN to ACC). In these cases, the code can be cleared and may not indicate a true fault.

Diagnosis Steps

1. Read the trouble codes with an OBD-II scanner capable of reading ABS/chassis codes. Note if there are any other codes present, especially P2771.
2. Check for specific symptom bytes if your scanner supports it. 'C0055 00' suggests a circuit fault (open/short), while 'C0055 5A' suggests an erratic/implausible signal.
3. Perform a thorough visual inspection of the VSS on the transmission (2WD) or transfer case (4WD). Check for physical damage or heavy metallic debris on its magnetic tip.
4. CRITICAL STEP: Carefully inspect the VSS wiring harness (typically purple and green/yellow wires) for damage, especially the section that runs over the top of the transmission where it is known to chafe against the housing or firewall.
5. Inspect the electrical connector for corrosion, moisture, or loose pins. A common pigtail replacement is Standard Motor Products S2412 or Dorman equivalents.
6. Using a scan tool, monitor the rear wheel speed sensor data while driving. 🎬 Watch: A pro walkthrough on properly diagnosing GM ABS codes The reading should be smooth and correspond to vehicle speed. If it is zero or erratic, the problem is likely the sensor or its wiring.
7. If possible, test the sensor's internal resistance with a multimeter. It should fall within the 1200-2900 ohm range.
8. Follow the diagnostic procedure in TSB #PIT4815C, which involves testing the circuit's voltage and continuity between the EBCM and the sensor connector. It specifically mentions checking the signal on circuit 817.
9. If the sensor and wiring are confirmed to be good, the final step is to test for a proper square wave signal at the EBCM itself using an oscilloscope. If the signal is present, the EBCM is the likely point of failure.

Parts You'll Likely Need

• Vehicle Speed Sensor (VSS) (OEM #ACDelco 213-4533) — This is the most common component to fail, triggering code C0055.
  Trusted brands: ACDelco (213-4533), Delphi, Standard Motor Products (SC168), Dorman (917-624)
  OEM price range: $45-$70
  Aftermarket price range: $25-$50
• VSS Connector Pigtail (OEM #ACDelco PT2298) — Needed if the wiring is damaged right at the sensor connector, or if the connector itself is corroded or broken. The harness chafe is a very common issue.
  Trusted brands: Dorman (645-207), ACDelco (PT2298), Standard Motor Products (S2412)
  OEM price range: $20-$40
  Aftermarket price range: $10-$25

Related Codes That Often Appear With This One

• P2771 —

Technical Service Bulletins (TSBs) & Recalls

• PIT4815C: Provides specific electrical diagnostic steps for when the Antilock Braking System Malfunction Indicator Lamp is on with only DTC C0055 set.
• PIP4966B: Links DTC C0055 with P2771 and points to possible internal mechanical wear (e.g., worn bushing, excessive tone wheel movement) in the transfer case or transmission as a root cause.
• 06-05-25-003: Informs that a history C0055 code can be set falsely by a specific ignition key sequence and may not require repair if no symptoms are present.

Platform-Specific Known Issues

• The VSS wiring harness is known to rub through on the top of the transmission/bellhousing area, causing a short or open circuit. This is a primary check before replacing parts.
• TSB #PIT4815C provides specific electrical diagnostic steps for when C0055 is the only code present.
• TSB #PIP4966B notes that in some cases, C0055 can be caused by an internal mechanical fault in the transmission or transfer case, like a worn bushing allowing the tone wheel to move excessively.
• TSB #06-05-25-003 indicates that a C0055 code in history without a current ABS light may be a software glitch and can be cleared.

Mechanic-Grade Diagnostic Values

• Vehicle Speed Sensor (VSS) internal resistance — expected: 1200 - 2900 Ohms. Failure: An open loop (OL), near 0 Ohms, or a reading significantly outside the expected range. One user measured a faulty sensor at 6.9 mega-ohms.
• VSS AC Signal Output (at sensor) — expected: A sine wave that increases in voltage and frequency with speed. Rises smoothly from <1V AC to over 5V AC as speed increases.. Failure: No AC voltage, or a jumpy/erratic reading while the driveshaft is turning.
• VSS Signal (at EBCM) — expected: A clean square wave signal.. Failure: A missing, distorted, or 'garbage' signal pattern on an oscilloscope indicates a problem with the wiring or the module that converts the signal (PCM/TCM).

Hidden / Shadow Codes Worth Checking

• C0055 00: Indicates the EBCM has detected a hard circuit fault, such as an open circuit, a short to ground, or a short to voltage in the rear wheel speed sensor circuit. This points directly to a wiring/connector issue or a completely failed sensor. (see via A professional scan tool capable of reading GM-specific ABS/EBCM codes and their symptom bytes (e.g., Tech2, GDS2, high-end Autel/Snap-on).)
• C0055 5A: Indicates the EBCM has detected an erratic or implausible signal from the rear wheel speed sensor. This often points to a failing sensor, a loose or damaged tone wheel inside the transmission/transfer case, or an intermittent wiring short that only appears under certain conditions (like acceleration). (see via A professional scan tool capable of reading GM-specific ABS/EBCM codes and their symptom bytes (e.g., Tech2, GDS2, high-end Autel/Snap-on).)

Wiring & Ground Locations

• EBCM Ground — On the frame rail directly under the driver's side door area.. A poor ground connection for the Electronic Brake Control Module (EBCM) is a common GM issue and can cause various communication and signal-related ABS codes, including C0055. Cleaning the contact point on the frame and the wire terminal is a critical diagnostic step.
• VSS Signal Wire (at Junction Block) — In a long black plug at the junction block to the left of the foot brake. The wire is typically green with a white stripe.. This is an accessible point to tap into the VSS signal wire for testing with a multimeter or oscilloscope without having to access the EBCM connector directly. It helps isolate whether the signal is lost before or after this point.
• VSS Signal Wires (at sensor) — The two wires running to the VSS sensor on the transmission/transfer case. Often a twisted pair of purple and yellow/green wires.. These specific wires are known to chafe on the top of the transmission bellhousing. TSB PIT4815C specifically references testing circuit 817, which is the VSS signal wire.

Real Owner Repair Stories

• DuramaxDiesels.com forum user (GMC Sierra HD with Duramax Diesel) — C0055 code present during data logging, but no ABS or brake lights on the dash. Transmission fluid leak from the transfer case slip yoke seal.
  ❌ Tried (didn't work) Checked wiring from TCM to sensor (all good), tested VSS resistance (read a normal 1362 ohms).
  ✅ What actually fixed it Another user confirmed the root cause was a failed rear bearing in the transfer case. This failure destroyed the extension housing bushing, allowing the output shaft to move excessively ('wallow around'), which caused the tone ring to physically contact and destroy the VSS. The fix required rebuilding the transfer case, not just replacing the sensor.
• YouTube video on a 2008 Chevy Silverado 2500 (2008 Chevrolet Silverado 2500 HD Duramax) — ABS light on with code C0055. Speedometer was working correctly.
  ❌ Tried (didn't work) N/A - Diagnosis was performed first.
  ✅ What actually fixed it Using a lab scope, the technician confirmed a good square wave signal was arriving at the EBCM connector. Since the signal was good but the module was setting a 'no signal' code, the EBCM itself was diagnosed as faulty. Replacing the electronic portion of the ABS module (held on by four Torx screws) resolved the code.

OEM Part Supersession History

• Various older GM part numbers (e.g., 19300586) → ACDelco 213-4533 (also listed as GM 19237463) — Part consolidation and potential design updates over the vehicle's lifecycle.
  Heads up: Some parts vendors incorrectly list ACDelco 213-4533 as an Oxygen Sensor, which can cause confusion during ordering. However, it is the correct VSS for this application.