C0055 on 2015-2019 GMC Canyon: Rear Wheel Speed Sensor Circuit Fault Guide

What's Unique About the 2015-2019 Gmc CANYON

The 2015-2019 GMC Canyon and its sibling, the Chevy Colorado, have a known issue documented in GM Technical Service Bulletin (TSB) #PIT5499B. A primary suspect for code C0055, especially if it appears with other ABS or communication codes, is water intrusion and corrosion at the main Electronic Brake Control Module (EBCM) connector. This specific vulnerability can cause a range of difficult-to-diagnose electrical issues within the ABS system. The TSB advises inspecting the EBCM connector for water and corrosion, and if found, replacing the EBCM and affected terminals.

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 Trailer Brake" message on the driver information center.
• ABS system may not activate during hard braking
• ABS may activate randomly at low speeds on dry pavement.
• Potential for erratic speedometer behavior or harsh transmission shifting (less common on this generation but possible)

Most Likely Causes

1. Faulty Rear Wheel Speed Sensor or Wiring 🔴 High Probability → Shop ABS Wheel Speed Sensor The sensor and its wiring are exposed to road debris, water, and salt, leading to physical damage, wire chafing, or corrosion over time. A frayed wire from rubbing on the CV axle was the confirmed cause for one owner.
   How to confirm: Use a scan tool to monitor live data from the rear wheel speed sensor while driving; an erratic or non-existent signal points to a bad sensor or wiring. Visually inspect the sensor and its harness for damage, and test the circuit with a multimeter. 🎬 Watch: A professional diagnostic walkthrough for ABS and StabiliTrak codes. A reading of OL (Open Loop) indicates a bad sensor.
   Typical fix: Replace the faulty rear wheel speed sensor and/or repair the damaged section of the wiring harness or connector pigtail.
   Est. part cost: $25-$75
2. Water Intrusion at EBCM Connector 🟡 Medium Probability As noted in TSB #PIT5499B, the main connector for the Electronic Brake Control Module, located on the driver-side frame rail, is susceptible to water intrusion, leading to corrosion on the connector pins.
   How to confirm: Disconnect the EBCM connector and carefully inspect for any signs of moisture, white or green corrosion ('green crusties'), or bent/damaged pins. This should be a primary check if multiple ABS codes are present.
   Typical fix: Clean the connector pins and module socket thoroughly with an electrical contact cleaner and a small brush. If corrosion is severe, the connector pigtail and/or EBCM may need to be replaced per the TSB. The source of the water leak must also be identified and sealed.
   Est. part cost: $5-$100 (cleaner) or $500+ (EBCM replacement)
3. Damaged Tone Ring 🟡 Medium Probability The magnetic tone ring (or reluctor ring), which the sensor reads, can be damaged by a failing bearing, rust buildup, or debris. On some GM trucks, a worn transfer case bushing can cause excessive output shaft play, allowing the tone ring to contact and damage the sensor. In other cases, rust can cause the ring to delaminate or crack.
   How to confirm: After confirming the sensor and wiring are good, remove the sensor and inspect the tone ring for cracks, missing teeth, heavy corrosion, or debris. One technician found a piece of the magnetic ring had broken off and was causing the issue.
   Typical fix: If the tone ring is part of the wheel hub, the entire hub and bearing assembly must be replaced. 🎬 Watch: How to replace the wheel hub and bearing assembly. If it's on the transfer case or differential, the component may need to be disassembled for repair.
   Est. part cost: $150-$300 (hub assembly)

Rare But Worth Checking

• Failed Electronic Brake Control Module (EBCM): → Shop ABS Control Module This is the least likely cause unless there is clear evidence of internal failure or severe, unrepairable corrosion at the connector. All other possibilities, especially wiring and connectors, should be exhaustively ruled out before condemning the expensive EBCM. However, a confirmed failure was documented where a good signal was present at the EBCM, but the module still set the code, proving an internal fault.
• Low or Failing Battery: On modern computer-controlled vehicles, a weak battery can cause a variety of seemingly unrelated electrical gremlins and warning lights. One owner on a Reddit forum reported that their intermittent Stabilitrak/ABS lights were resolved after replacing an aging battery.

Diagnosis Steps

1. Connect an OBD-II scanner capable of reading ABS codes. Confirm C0055 is present and note any other codes, especially communication codes (U-codes) or other wheel speed sensor faults. Check for symptom bytes like '00' or '5A' for more specific direction.
2. Use the scanner's live data function to monitor the speed signals from all wheels while driving. The signal for the rear sensor should be erratic, jumpy, or absent compared to the others.
3. CRITICAL STEP FOR THIS PLATFORM: Locate the Electronic Brake Control Module (EBCM) on the driver's side frame rail. Disconnect its main electrical connector and carefully inspect both sides for any signs of water damage, pin corrosion, or bent pins, as highlighted in TSB #PIT5499B.
4. If the EBCM connector is clean, raise the vehicle and perform a thorough visual inspection of the rear wheel speed sensor and its wiring harness. Look for breaks, chafing, or corrosion at the connector. Follow the harness and check all mounting clips.
5. If the wiring looks good, remove the sensor (typically held by a single bolt) and inspect 🎬 See this step-by-step guide for replacing the wheel speed sensor. its tip for metal shavings or damage.
6. With the sensor removed, use a borescope or a good flashlight to inspect the magnetic tone ring inside the housing for cracks, damage, or heavy rust buildup.
7. Check for play in the related component (wheel bearing or driveshaft/yoke) to see if a failing bearing is allowing the tone ring to move excessively.
8. If no external faults are found, test the sensor's circuit. With a multimeter set to Ohms, check the resistance at the sensor's connector. An open circuit (OL) indicates a failed sensor. Compare the reading to a known good sensor if possible.
9. For advanced diagnosis, use a lab scope to check for a clean square wave signal at the EBCM connector. If a good signal is present but the code persists, the EBCM is likely faulty.
10. Only after all other possibilities have been eliminated should the EBCM itself be considered faulty.

Parts You'll Likely Need

• Rear Wheel Speed Sensor (OEM #84307017, 23299335, 22951116) — This sensor is a common failure item due to its exposed location. It is often the direct cause of the C0055 code. Part number can vary by specific model year and 2WD/4WD configuration. Part number 84307017 supersedes 84199449.
  Trusted brands: ACDelco (GM Genuine), Delphi, Standard Motor Products
  OEM price range: $40-$90
  Aftermarket price range: $25-$60
• Rear Wheel Hub and Bearing Assembly — The magnetic tone ring is integrated into the hub on models with rear wheel sensors at the hub. If the ring is damaged or the bearing fails, the entire assembly must be replaced to restore a proper sensor signal.
  Trusted brands: ACDelco, Timken, MOOG
  OEM price range: $250-$400
  Aftermarket price range: $150-$250
• Wheel Speed Sensor Connector Pigtail — The connector at the sensor is prone to corrosion or wire fatigue, requiring it to be cut out and replaced with a new pigtail.
  Trusted brands: ACDelco, Dorman (e.g., 645-134), Standard Motor Products
  OEM price range: $30-$50
  Aftermarket price range: $15-$30

Related Codes That Often Appear With This One

• C0035, C0040, C0045, C0050 — These are codes for the other wheel speed sensors. When multiple wheel speed sensor codes appear at once, it strongly suggests a common problem like a faulty EBCM, a bad ground, or the water intrusion issue at the EBCM connector mentioned in TSB #PIT5499B.
• U0121, U0415, U0420 — These are communication codes indicating a loss of communication with the ABS module or implausible data. Their presence alongside C0055 reinforces the likelihood of a major electrical issue, such as the EBCM connector corrosion detailed in TSB #PIT5499B.

Technical Service Bulletins (TSBs) & Recalls

• PIT5499B

Platform-Specific Known Issues

• Technical Service Bulletin #PIT5499B points to a known problem with water intrusion and corrosion at the Electronic Brake Control Module (EBCM) connector, which can trigger code C0055 along with other ABS and communication faults.
• On 4WD models, a worn transfer case output shaft bushing can cause play in the driveshaft, leading to contact between the tone ring and the speed sensor, generating a C0055 code.

Mechanic-Grade Diagnostic Values

• Rear Wheel Speed Sensor Resistance — expected: No GM-specific value found, but should not be an open circuit (OL). Compare reading with a known-good sensor from the other side of the vehicle; values should be very close (within a few percent). Some GM sensors read in the Mega-Ohm (MΩ) range.. Failure: A reading of OL (Open Loop) on a multimeter indicates a failed sensor. A significant difference in resistance from a known-good sensor also indicates failure.
• Rear Wheel Speed Sensor AC Voltage Output — expected: At least 200mV (0.2 VAC) when spinning the wheel at approximately 1 revolution per second.. Failure: No voltage or significantly lower voltage than specified indicates a faulty sensor or a problem with the tone ring.
• Rear Wheel Speed Sensor Signal Waveform — expected: A clean, consistent square wave pattern that increases in frequency as wheel speed increases.. Failure: A missing, erratic, or 'garbage' waveform indicates a problem with the sensor, tone ring, or wiring.

Hidden / Shadow Codes Worth Checking

• C0055 00: Indicates the EBCM has detected a short to ground, short to voltage, or an open/high resistance condition in the rear wheel speed sensor circuit. This points towards an electrical wiring or sensor internal fault. (see via A professional-level scan tool (like GM's GDS2/Tech2) that can read manufacturer-specific symptom bytes.)
• C0055 5A: Indicates the EBCM has detected an erratic or implausible signal from the rear wheel speed sensor. This often points to a mechanical issue like a damaged tone ring, a failing wheel bearing, or excessive sensor air gap, rather than a simple open/short circuit. (see via A professional-level scan tool (like GM's GDS2/Tech2) that can read manufacturer-specific symptom bytes.)
• C0055 0F: Indicates the rear speed sensor is showing erratic operation. Similar to the 5A symptom byte, this suggests a signal integrity problem. (see via A professional-level scan tool (like GM's GDS2/Tech2).)

Scan Tool Commands That Help

• GDS2 / Professional Scan Tool: Live Data > EBCM > Wheel Speed Sensors — This is the primary first step. Use the graphing function to visually compare the signal from the rear sensor to the other three sensors while driving. Dropouts, erratic spikes, or a flat line on the rear sensor graph instantly confirms the fault location.
• GDS2 / J2534 Programmer: Service Programming System (SPS) — This is mandatory after replacing the Electronic Brake Control Module (EBCM). The new module must be programmed with the vehicle's VIN and specific configuration to function correctly.
• GDS2 / Professional Scan Tool: Automated Bleed / ABS Bleed Procedure — This is required only if the hydraulic portion of the ABS unit (the Brake Pressure Modulator Valve or BPMV) has been replaced or if the system has been opened, allowing air to enter. It cycles the internal valves and pump to purge trapped air.

Wiring & Ground Locations

• EBCM Connector — On the Electronic Brake Control Module, which is mounted to the driver's side frame rail.. This is the central connection point for all wheel speed sensors. It is the specific location cited in TSB #PIT5499B for water intrusion and corrosion, which can directly cause code C0055. Testing the sensor signal here can determine if the fault is in the module or downstream in the wiring/sensor.
• Underhood Fuse Block — On the driver's side of the engine bay.. Contains the primary fuses and relays for the ABS system. A loss of power or a faulty relay here can disable the entire EBCM, often setting multiple communication codes along with sensor codes.
• Passenger Compartment Fuse Block — Behind a small door in the passenger side kick panel area.. May contain secondary fuses related to the EBCM or other control modules that communicate with the ABS system.

Real Owner Repair Stories

• YouTube user 'The Average Joe' (2018 Chevy Colorado Z71 4WD) — ABS, Traction, and Stabilitrak lights came on. ABS would randomly activate during normal braking. A basic OBD2 scanner did not pull any codes.
  ❌ Tried (didn't work) Initial scan with a basic code reader yielded no information.
  ✅ What actually fixed it A visual inspection revealed the wheel speed sensor wire had become detached from its mount, rubbed against the CV axle, and was frayed. Replacing the front wheel speed sensor and harness assembly resolved all symptoms and warning lights.
• YouTube user 'Ben's Garage' (2017 Chevy Colorado) — ABS and brake lights on, humming noise, intermittent signal from left front wheel speed sensor (code C0045).
  ❌ Tried (didn't work) Initial diagnosis was inconclusive without physical inspection.
  ✅ What actually fixed it After removing the wheel speed sensor for inspection, the technician found that a piece of the magnetic encoder ring from the wheel bearing had broken off and was stuck to the sensor's magnetic tip, causing an erratic signal. Replacing the wheel bearing assembly (which includes the tone ring) and the damaged sensor fixed the problem.
• YouTube user 'Weber Auto' (2008 Chevy Silverado 2500 (similar GM truck system)) — ABS light on with code C0055. Speedometer worked correctly.
  ❌ Tried (didn't work) The VSS sensor on the transfer case was known to be good because the speedometer was functional.
  ✅ What actually fixed it Using a lab scope, the technician confirmed a perfect square wave signal from the sensor was arriving at the EBCM connector. Because the EBCM was receiving a good signal but still setting a 'no signal' code, the EBCM itself was condemned as faulty. Replacing the EBCM resolved the code.

When the Usual Fixes Don't Work

• While many guides and mechanics state that the Electronic Brake Control Module (EBCM) is rarely the cause of a single wheel speed sensor code, there are documented cases where it is the confirmed point of failure. In one instance involving a C0055 code on a GM truck, a technician used an oscilloscope to prove a perfect signal was reaching the EBCM. Because the module was receiving the correct data but still setting the fault code, it was definitively diagnosed as an internal module failure. This demonstrates that while the EBCM should not be the first part replaced, it should not be completely ruled out, and can be condemned with certainty using advanced diagnostic tools.

OEM Part Supersession History

• 84199449 → 84307017 — Likely an updated design for improved durability or performance. This is a common practice for parts in high-failure locations.
  Heads up: The new part number (84307017) is listed as the correct replacement for the original. No incompatibility is noted.

Model Year Variations Within This Range

• 2015-2016 vs 2017-2019: The original rear wheel speed sensor part number was likely 84199449 for early models, which was later superseded by 84307017 for 2017 and newer models. While likely interchangeable, it's best to use the latest revision for repairs.