C0045 on 2015-2019 Chevrolet Colorado: Left Rear Wheel Speed Circuit Causes and Fixes

What's Unique About the 2015-2019 Chevrolet COLORADO

On the second-generation Colorado and its platform-mate, the GMC Canyon, the wheel speed sensor is integrated into the wheel hub bearing assembly. While the hub itself can fail, a notable issue for this platform and related GM trucks is wiring and connector problems. A specific GM Technical Service Bulletin, PIT5499B, points to water intrusion and corrosion at the main EBCM connector as a potential cause for a group of wheel speed sensor codes, including C0045. This makes checking the EBCM connector, located on the frame rail under the driver's side, a critical first step before assuming the hub has failed. Additionally, wiring harnesses on these trucks are known to be susceptible to chafing against chassis components, which can also cause this code.

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/Traction Control warning light is on
• "Service StabiliTrak" or "Service Trailer Brake" message on the Driver Information Center [PIT5499B]
• ABS and traction control are disabled
• Cruise control may be inoperative

Most Likely Causes

1. Water Intrusion/Corrosion at EBCM Connector 🔴 High Probability A known issue documented in TSB #PIT5499B for the 2015 model year, which can affect a range of GM trucks. The EBCM connector's location on the driver-side frame rail makes it susceptible to moisture and road spray, leading to corrosion on the pins. [PIT5499B]
   How to confirm: Disconnect the battery. Unplug the large main connector at the Electronic Brake Control Module (EBCM) and inspect for any signs of moisture, green or white corrosion, or backed-out/damaged pins. [PIT5499B] The issue often affects multiple pins, potentially triggering other wheel speed sensor codes simultaneously.
   Typical fix: Clean the connector and pins using a specialized electronics cleaner and a small brush if corrosion is minor. If corrosion is severe or pins are damaged, the connector pigtail may need to be replaced. Apply dielectric grease to the seal upon reassembly to prevent future moisture intrusion.
   Est. part cost: $20-$70
2. Damaged Wheel Speed Sensor Wiring Harness 🟡 Medium Probability → Shop ABS Wheel Speed Sensor The wiring harness running from the frame to the wheel hub is exposed to suspension movement, road debris, and heat. Several TSBs and owner reports on Colorados and other GM trucks highlight issues with harnesses chafing on frame brackets, suspension components, or heat shields, leading to short or open circuits.
   How to confirm: Visually inspect the entire length of the harness from the sensor connector to where it enters the main loom. Pay close attention to areas where the harness is secured by clips or runs near sharp metal edges, like the frame or control arms. Perform a continuity and resistance test on the wires between the sensor and the EBCM.
   Typical fix: Repair the damaged section of wire using solder and heat-shrink tubing. If the damage is extensive or near a connector, replace the pigtail. Reroute the harness slightly or add protective conduit to prevent future chafing.
   Est. part cost: $15-$50
3. Faulty Left Rear Wheel Hub & Bearing Assembly 🟡 Medium Probability → Shop Hub Assembly The wheel speed sensor is integrated into the hub assembly. The internal magnetic encoder ring (tone ring) can become damaged from rust, get contaminated with metallic debris, or crack, causing an erratic or missing signal.
   How to confirm: After ruling out wiring, use a scan tool to monitor live data from the left rear wheel speed sensor while driving. If the signal is erratic, drops out, or doesn't match the other wheels, the hub is likely faulty. A visual inspection of the back of the hub may reveal a cracked, swollen, or debris-covered encoder ring. You can also check for physical play in the bearing, which would indicate a mechanical failure.
   Typical fix: Replace the entire left rear wheel hub and bearing assembly.
   Est. part cost: $100-$250

Rare But Worth Checking

• Failed Electronic Brake Control Module (EBCM): → Shop ABS Control Module This is rare and should only be considered after all other possibilities (sensor, hub, and wiring) have been thoroughly ruled out. An EBCM failure will typically set multiple, often persistent, codes that do not clear, or communication codes like U0121.

Diagnosis Steps

1. Connect an OBD-II scanner capable of reading ABS codes to confirm C0045 is present and note any other codes.
2. Use the scanner to view live data. Monitor the wheel speed signals from all four wheels while driving. Confirm that the left rear sensor provides an erratic, inconsistent, or absent signal compared to the others.
3. Perform a thorough visual inspection of the main connector at the Electronic Brake Control Module (EBCM) for water intrusion or corrosion, as per TSB #PIT5499B. This is a high-probability cause. [PIT5499B]
4. Thoroughly inspect the left rear wheel speed sensor wiring harness from the hub to the main chassis loom. Look for any signs of damage, chafing against the frame or suspension, melting near the exhaust, or corrosion.
5. If wiring and connectors appear intact, test the circuit. Disconnect the harness at the EBCM and the wheel speed sensor. Check for continuity, shorts to ground, and shorts to power on the signal and reference wires.
6. Inspect the magnetic encoder ring on the back of the wheel hub for cracks, swelling, or contamination with metallic debris.
7. If the wiring, connectors, and encoder ring are all good, the fault is most likely internal to the wheel speed sensor. Replacing the left rear wheel hub assembly is the next step.
8. After repair, clear the codes and perform a test drive to ensure the lights do not return.
9. If the problem persists after replacing the hub, the EBCM may be faulty, though this is the least likely cause.

Parts You'll Likely Need

• Rear Wheel Hub and Bearing Assembly (OEM #13519422) — The wheel speed sensor is integrated into this assembly. Failure of the sensor or its magnetic encoder ring is a primary cause of C0045 after wiring issues are ruled out. Note: Part number may vary by 2WD/4WD configuration.
  Trusted brands: ACDelco (GM Genuine), MOOG, Timken, SKF
  OEM price range: $180-$250
  Aftermarket price range: $100-$180
• EBCM Connector Pigtail — The main EBCM connector can corrode due to water intrusion, requiring replacement if cleaning is not possible. [PIT5499B]
  Trusted brands: ACDelco, Dorman
  OEM price range: $40-$80
  Aftermarket price range: $25-$50
• Wheel Speed Sensor Harness Connector/Pigtail — The connector at the wheel hub can corrode or have damaged wires from exposure and movement.
  Trusted brands: ACDelco, Dorman
  OEM price range: $30-$60
  Aftermarket price range: $15-$40

Related Codes That Often Appear With This One

• C0035 — Relates to the Right Front Wheel Speed Sensor. If seen with C0045, it could point to a systemic issue like the EBCM connector problem mentioned in TSB #PIT5499B. [PIT5499B]
• C0040 — Relates to the Left Front Wheel Speed Sensor. If seen with C0045, it could point to a systemic issue like the EBCM connector problem mentioned in TSB #PIT5499B. [PIT5499B]
• C0050 — Relates to the Right Rear Wheel Speed Sensor. If seen with C0045, it could point to a systemic issue like the EBCM connector problem mentioned in TSB #PIT5499B. [PIT5499B]
• U0121 — Indicates a loss of communication with the ABS control module. This can also be caused by the EBCM connector water intrusion issue cited in TSB #PIT5499B. [PIT5499B]

Technical Service Bulletins (TSBs) & Recalls

• PIT5499B

Platform-Specific Known Issues

• TSB #PIT5499B documents an issue on 2015 models where water intrusion into the Electronic Brake Control Module (EBCM) connector can cause C0045 along with other ABS and communication codes. This is a well-known issue across similar GM trucks and SUVs. [PIT5499B]
• General wire harness chafing is a common problem on this platform. Owners on forums like Reddit and ColoradoFans report finding harnesses rubbing on frame members, AC lines, and engine components, which can cause a variety of electrical issues, including wheel speed sensor circuit faults.

Mechanic-Grade Diagnostic Values

• Digital Wheel Speed Sensor Signal (at EBCM) — expected: A square wave that switches between approximately 0.7V and 1.8V as the wheel is spun.. Failure: A signal that is stuck high, stuck low, or shows no activity when the wheel is turning.
• Wheel Speed Sensor AC Voltage Output (Passive Sensor Test) — expected: At least 200mV (0.2 VAC) when spinning the wheel at about one revolution per second.. Failure: Voltage is significantly lower or absent, indicating a weak or dead sensor/encoder.
• Wheel Speed Sensor Circuit Resistance — expected: 800 to 1400 ohms is a typical range for older passive sensors. Digital sensors on the Colorado may not have a meaningful resistance spec and should be tested with voltage checks.. Failure: A reading that is open (infinite) or shorted (near zero ohms).

Hidden / Shadow Codes Worth Checking

• C0045 0F: Signal Erratic. The EBCM has detected a signal that is unstable or fluctuating illogically. This is often caused by a damaged magnetic encoder ring on the hub, metallic debris on the sensor, or electrical interference. (see via A professional scan tool like the GM GDS2 or Tech2 that can read ABS symptom bytes (sub-codes).)
• C0045 18: Signal Circuit Low Signal Amplitude / Missing Signal. This suggests a complete loss of signal from the sensor, often due to a failed sensor, an open circuit in the wiring, or a fully disconnected connector. (see via A professional scan tool like the GM GDS2 or Tech2 that can read ABS symptom bytes (sub-codes).)
• C0045 5A: Signal Plausibility Failure. The EBCM is receiving a signal from the left rear sensor that is illogical when compared to the signals from the other three wheels. This can be caused by a severely damaged tone ring, an incorrect part, or a significant difference in tire size on one corner of the vehicle. (see via A professional scan tool like the GM GDS2 or Tech2 that can read ABS symptom bytes (sub-codes).)
• C0045 06: Signal Circuit Low Voltage/Open. This points specifically to an open wire, a short to ground, or high resistance in the circuit wiring. (see via A professional scan tool like the GM GDS2 or Tech2 that can read ABS symptom bytes (sub-codes).)

Scan Tool Commands That Help

• GM GDS2 / Tech2: Live Data - Wheel Speed Sensors — This is the primary diagnostic step. Monitor the km/h or MPH reading from all four sensors while driving in a straight line. The faulty sensor will read 0, lag behind, or show an erratic value compared to the other three.
• GM GDS2 / Tech2: Automated Bleed Procedure — This service function is required *after* replacing the EBCM or the hydraulic modulator unit (BPMV) to purge trapped air from the ABS pump and valve body. It is not needed for just a sensor replacement.

Wiring & Ground Locations

• EBCM Connector (X1) — On the Electronic Brake Control Module, which is mounted to the driver's side frame rail, below the driver's door.. This is the main connector for the entire ABS system. TSB #PIT5499B specifically calls out this connector for water intrusion and corrosion, which can directly cause code C0045. The Left Rear WSS Signal wire is at Pin 34, and the Low Reference (ground) is at Pin 33.
• Pin 34 at EBCM Connector — In the main 38-pin EBCM connector.. This is the Left Rear Wheel Speed Sensor Signal wire, typically a Gray/White wire. This is the specific pin to test for the square wave signal coming from the sensor.
• Pin 33 at EBCM Connector — In the main 38-pin EBCM connector.. This is the Left Rear Wheel Speed Sensor Low Reference (ground) wire, typically a Gray/Black wire. A break in this wire will cause a loss of signal.
• G303 — Located on the left kick panel area, inside the cabin.. This is a major chassis ground point. While not the direct ground for the sensor circuit itself (which is a low reference from the EBCM), a poor main ground for the EBCM can cause a variety of erratic electrical issues, including ABS faults.

Real Owner Repair Stories

• YouTube channel 'OldGuyDIY' (General Motors vehicle (Buick Lucerne, but a common GM issue)) — ABS and Traction Control lights on with code C0045.
  ❌ Tried (didn't work) Replacing the entire wheel hub assembly, which included a new sensor.
  ✅ What actually fixed it The female pins in the vehicle-side wiring harness connector had spread apart, causing a poor connection with the new sensor's male pins. The fix was to carefully insert small strands of copper wire into the female terminals to create a tighter, more reliable connection, which resolved the code.
• YouTube channel 'Wheel Speed ABS Sensor Replacement...' (2018 Chevy Colorado Z71 4WD 3.6L) — ABS, Traction, and Stabilitrak warning lights came on after off-roading. Occasional random ABS activation during normal braking.
  ❌ Tried (didn't work) Using a basic OBD scanner, which did not pull any codes.
  ✅ What actually fixed it A visual inspection revealed that the wheel speed sensor wire was visibly frayed. Replacing the sensor and its integrated wiring harness fixed the problem and cleared the lights.
• Reddit user RickMN on r/AskMechanics (2011 Chevy Equinox (similar hub/sensor design)) — C0045 code returned shortly after replacing the wheel speed sensor.
  ❌ Tried (didn't work) Replacing the wheel speed sensor.
  ✅ What actually fixed it The suggested fix was to inspect the magnetic encoder ring on the wheel bearing for metallic debris. These particles can interfere with the sensor's reading. Cleaning the magnetic ring can often resolve the issue without replacing any parts.

OEM Part Supersession History

• 13519422 (Rear Wheel Hub Assembly) → 13534553 — Standard part revision or change in manufacturer by GM.
  Heads up: The new part number is a direct replacement for the original.
• 23354053 (EBCM for 2015 model) → Multiple part numbers exist depending on year and options. Examples include 84214765, 84004231. — Part updates and variations between model years and vehicle options (e.g., trailer brake controller).
  Heads up: The EBCM is highly specific to the vehicle's VIN and options. A replacement module, new or used, MUST be programmed by a dealer or qualified shop using GM's Service Programming System (SPS) to function. It is not a plug-and-play part.

Model Year Variations Within This Range

• 2015-2019: The wheel speed sensors used on this generation are digital (magneto-resistive) types. They are powered by the EBCM and produce a digital square wave signal. This is different from older passive (variable reluctance) sensors that generate their own AC voltage. Testing a digital sensor with an ohmmeter may not yield conclusive results; checking for a voltage signal with a multimeter or oscilloscope is the correct method.