C0045 on 2009-2017 Chevrolet Traverse: Left Rear Wheel Speed Sensor Circuit Fault Causes and Fixes

What's Unique About the 2009-2017 Chevrolet Traverse

On the first-generation Traverse and its GM Lambda platform mates (Buick Enclave, GMC Acadia, Saturn Outlook), this code is frequently triggered by one of two common issues. The first is a simple failure of the wheel speed sensor itself or its exposed wiring. The second, and a very common GM issue, is the failure of the magnetic encoder ring that is integrated into the wheel hub and bearing assembly. This ring can rust, crack, or delaminate due to 'rust jacking', providing a faulty or incomplete signal to the sensor. Metallic debris can also stick to the magnetic ring, causing false readings and unwanted ABS activation at low speeds.

Symptoms You May Notice

• ABS warning light is illuminated
• StabiliTrak or Traction Control warning light is illuminated
• "Service StabiliTrak" or "Service Traction Control" message on the driver information center
• ABS system is disabled
• Traction control system is disabled
• Brake pedal may pulsate or ABS may activate unnecessarily at low speeds
• A grinding or ugly sound from a wheel area during braking as the ABS system tries to compensate for the bad signal
• In some instances, an owner reported the check engine light returning alongside C0045 and fuel system codes P0463 and P069E, as noted in NHTSA ODI #11399819.

Most Likely Causes

1. Faulty Left Rear Wheel Speed Sensor 🔴 High Probability The sensor is exposed to weather, road debris, and corrosion, which can cause it to fail internally or become damaged. Manufacturer Bulletin #PIE0533A notes that field information was previously gathered specifically for wheel speed sensors becoming inoperative with codes including C0045.
   How to confirm: Use a scan tool to monitor live data from all four wheel speed sensors while driving. The left rear sensor will show erratic readings, dropouts, or no signal compared to the others. You can also test the sensor's resistance with a multimeter (typically should be between 800-2000 ohms, but verify specs for your specific part). An oscilloscope provides the most definitive test by visualizing the sensor's waveform.
   Typical fix: Replace the left rear wheel speed sensor. The sensor is typically held in by a single 10mm bolt. The mounting hole in the knuckle should be cleaned thoroughly with a bore brush before installing the new sensor to ensure proper seating and air gap. 🎬 See this step-by-step rear ABS sensor replacement walkthrough.
   Est. part cost: $30-$70
2. Damaged Magnetic Encoder Ring on Wheel Hub Assembly 🔴 High Probability The magnetic ring is built into the seal of the wheel bearing. Rust can form under the ring ('rust jacking'), causing it to crack, swell, or delaminate from the bearing. This creates an inconsistent or missing surface for the sensor to read, which is a very common failure on this platform.
   How to confirm: After ruling out the sensor and wiring, remove the brake rotor to get a clear view of the magnetic ring on the back of the wheel hub. Look for cracks, rust jacking, or pieces of the ring that have broken off or are missing. Sometimes metallic debris can stick to the magnet and disrupt the signal.
   Typical fix: The magnetic ring is not serviced separately. The entire wheel hub and bearing assembly must be replaced.
   Est. part cost: $100-$250
3. Damaged or Corroded Wiring/Connector 🟡 Medium Probability The wiring harness runs along the suspension and is susceptible to damage from road debris, moisture, and flexing. The connector pins can also corrode, leading to a poor connection. Manufacturer Bulletin #PIT5427B suggests that technicians should inspect the X411 connector for damage when C0045 is present.
   How to confirm: Visually inspect the entire wiring harness from the sensor to the main chassis connector for any cuts, chafing, or corrosion. Wiggle the connector and harness while monitoring live sensor data on a scan tool to see if the signal changes. Check for TSBs like PI0934, which note that terminals can back out of the connector.
   Typical fix: Repair the damaged section of wire or replace the pigtail connector. Ensure the repaired harness is properly secured away from moving parts. Per TSB PI0934, if a terminal has backed out, the entire connector pigtail should be replaced, not just re-seated. An example pigtail is Standard Motor Products S-824 or AC Delco PT2160.
   Est. part cost: $15-$40
4. Worn or Failed Wheel Bearing ⚪ Low Probability A worn bearing allows for excessive play ('wobble') in the hub. This movement changes the critical air gap between the sensor and the magnetic ring, causing the signal to become erratic. This is less common than the magnetic ring failing on its own.
   How to confirm: With the vehicle safely raised, try to rock the wheel at the 12 and 6 o'clock positions. Any noticeable play or humming/grinding noise when spinning the wheel indicates a bad bearing.
   Typical fix: Replace the wheel hub and bearing assembly. This also replaces the problematic magnetic encoder ring.
   Est. part cost: $100-$250

Rare But Worth Checking

• Failed Electronic Brake Control Module (EBCM): This is rare. Only consider this after exhaustively testing the sensor, wiring, and hub assembly. An EBCM failure would likely present other codes or symptoms as well. Manufacturer Bulletin #PIT5499B notes that water intrusion at the EBCM connector can trigger C0045. The module is located under the hood behind the air filter housing and requires programming after replacement.

Diagnosis Steps

1. Connect an ABS-capable scan tool and confirm C0045 is the active code. Note any symptom bytes like '-00' or '-5A'.
2. View live data from all four wheel speed sensors. Drive the vehicle slowly (or spin the wheel by hand with the vehicle raised) and observe the reading from the Left Rear (LR) sensor. Compare it to the Right Rear (RR) sensor. Look for dropouts, erratic jumps, or a zero reading.
3. Raise and support the rear of the vehicle. Visually inspect the wheel speed sensor wiring harness for any obvious damage, corrosion, or improper routing. Check that it is secured in all its clips.
4. Disconnect the sensor and inspect the connector pins for corrosion or damage. Check for backed-out terminals as described in TSB PI0934.
5. Remove the 10mm bolt holding the sensor. Carefully remove the sensor from the knuckle. It may be seized due to corrosion; gentle twisting with pliers may be necessary. Be prepared for it to break.
6. Inspect the sensor tip for debris or damage. Clean the mounting hole in the knuckle with a wire bore brush before installing a new sensor.
7. Remove the brake caliper and rotor to get a clear view of the wheel hub assembly. Closely inspect the magnetic encoder ring on the hub for cracks, rust, swelling, or missing sections.
8. If the wiring looks good and the hub's magnetic ring is intact, the sensor itself is the most likely culprit. Replace the sensor.
9. If the magnetic ring is damaged, the entire wheel hub and bearing assembly must be replaced.
10. After replacement, clear the codes with a scan tool and perform a test drive to ensure the light does not return.

Parts You'll Likely Need

• Left Rear Wheel Speed Sensor (OEM #22894913 (ACDelco), 23483153 (ACDelco Gold)) — This is the most direct cause of a circuit fault and is a common failure item due to its exposed location.
  Trusted brands: ACDelco, Delphi, Standard Motor Products (ALS2039), TRQ (BSA15913)
  OEM price range: $50-$80
  Aftermarket price range: $30-$70
• Left Rear Wheel Hub and Bearing Assembly (OEM #ACDelco FW403 or FW331 (Verify by VIN)) — Required if the integrated magnetic encoder ring is rusted, cracked, or damaged, which is a frequent cause of this code on GM Lambda platforms.
  Trusted brands: ACDelco, Timken, MOOG, SKF
  OEM price range: $200-$300
  Aftermarket price range: $100-$250
• ABS Wheel Speed Sensor Connector Pigtail (OEM #ACDelco PT2160) — Needed if the connector itself or the wiring near it is corroded or damaged. TSB PI0934 advises replacement if terminals have backed out.

Related Codes That Often Appear With This One

• C0050 — If C0050 (Right Rear Wheel Speed Sensor Circuit) is also present, it points towards a shared wiring or connector issue further up the harness, or a problem with the EBCM, rather than two simultaneous sensor failures.
• C0561 — This code for 'System Disabled Information Stored' is often a companion code, indicating the EBCM has disabled the StabiliTrak system as a result of the primary fault (like C0045).

Technical Service Bulletins (TSBs) & Recalls

• PI0934: While for the 2013 Equinox/Terrain, this TSB is relevant as it describes the exact same failure mode for C0045/C0050 where harness terminals are not fully seated in the connector, causing an intermittent signal. It advises replacing the connector pigtail, not just re-seated.
• Bulletin #PIE0533A: This bulletin addresses wheel speed sensor inoperative conditions resulting in DTC C0045.
• Bulletin #PIT5499B: This bulletin notes that technicians may find code C0045 and should inspect the Electronic Brake Control Module connector for water intrusion.
• Bulletin #PIT5427B: This bulletin indicates that for codes including C0045, technicians should inspect the X411 connector for damage.

Platform-Specific Known Issues

• The magnetic encoder ring on the wheel bearing is known to fail due to rust and delamination, causing an erratic signal that triggers code C0045. This is a widely documented issue on the GM Lambda platform.
• Sensors can become heavily corroded and seized into the rear knuckle, making removal difficult without breaking the sensor. Applying penetrating oil beforehand and using a bore brush to clean the hole are recommended.
• The wiring harness connector terminals can become unseated, causing an intermittent connection. TSB PI0934 addresses this for the similar Equinox/Terrain platform, but the principle applies.

Mechanic-Grade Diagnostic Values

• Wheel Speed Sensor Resistance — expected: 800 - 2000 Ohms (varies by manufacturer, but this is a common range for passive sensors).. Failure: A reading of OL (open circuit) or near 0 Ohms (short circuit) indicates a failed sensor.
• Wheel Speed Sensor AC Voltage Output (Passive Sensor) — expected: Greater than 0.25 Volts AC while spinning the wheel by hand at about half a revolution per second.. Failure: Voltage is less than 0.25V AC, indicating a weak or dead sensor, or an excessive air gap.
• EBCM Ground Bolt Torque — expected: 9 N·m (79 lb in).. Failure: A loose ground bolt can cause intermittent ABS/Stabilitrak issues.

Hidden / Shadow Codes Worth Checking

• C0045 00: Indicates a general circuit malfunction, such as an open circuit, short to ground, or short to voltage. (see via GM GDS2 or other professional scan tool capable of reading manufacturer-specific symptom bytes.)
• C0045 5A: Indicates a 'Plausibility Failure'. The EBCM receives a signal, but it doesn't logically match the signals from other wheels. This often points to a mechanical issue like a cracked tone ring or excessive wheel bearing play. (see via GM GDS2 or other professional scan tool capable of reading manufacturer-specific symptom bytes.)
• C0045 0F: Indicates the signal from the sensor is erratic. This often points to a damaged magnetic encoder ring, debris on the sensor, or a wiring issue. (see via GM GDS2 or other professional scan tool capable of reading manufacturer-specific symptom bytes.)
• C0045 18: Indicates 'Signal Amplitude Less Than Minimum'. The signal is too weak, which is a classic symptom of an increased air gap due to rust jacking or a failing sensor. (see via GM GDS2 or other professional scan tool capable of reading manufacturer-specific symptom bytes.)

Scan Tool Commands That Help

• GDS2 / High-End Scan Tool: Live Data Graphing - Wheel Speed Sensors — This is the primary diagnostic step. Graphing all four wheel speed sensors on one screen while driving allows for direct comparison. A faulty sensor circuit will show as a flat line, erratic drops, or a 'noisy' signal compared to the other three smooth lines.

Wiring & Ground Locations

• EBCM Location — Under the hood on the right (passenger) side, located behind the air filter housing.. This is the control module that receives the signal from the left rear wheel speed sensor. All wiring for the sensor ultimately terminates here.
• EBCM Ground (G110 on some models) — Typically located on the frame rail beneath the driver's side door. It is identifiable as a heavy (approx. 12-gauge) black wire. Some diagrams also show a G110 ground on the right rear of the engine cylinder head.. A poor ground connection for the EBCM can cause a host of intermittent and difficult-to-diagnose ABS and Stabilitrak faults, including false wheel speed sensor codes. Cleaning this ground point is a known fix for various ABS issues on GM trucks and SUVs.
• ABS Fuses — In the main underhood fuse box, typically two fuses (e.g., a 40A and a 25A) are responsible for powering the ABS motor and module.. While a blown fuse is unlikely to cause a single sensor code, it's a simple preliminary check that ensures the EBCM has power.

Real Owner Repair Stories

• YouTube user 'Pine Hollow Auto Diagnostics' (Chevrolet Traverse (year not specified, but first generation)) — ABS and Stabilitrak lights on, code C0045.
  ❌ Tried (didn't work) Initial diagnosis only.
  ✅ What actually fixed it The technician graphed the live wheel speed data and saw a very 'glitchy' and erratic signal from the left rear sensor compared to the others. Based on the high prevalence of 'rust jacking' on these vehicles, he immediately diagnosed a failed magnetic reluctor ring on the hub. The final fix was to replace both the wheel hub bearing assembly and the wheel speed sensor at the same time to ensure a complete repair.
• YouTube user 'The Car Care Nut' (2012 Chevrolet Traverse) — ABS light on, code C0045.
  ❌ Tried (didn't work) The vehicle had already had both rear wheel bearings replaced because the tone rings had failed, but the C0045 code remained.
  ✅ What actually fixed it After replacing the known-bad wheel bearings/tone rings, the final remaining fault was the wheel speed sensor itself. Replacing the left rear wheel speed sensor cleared the code.
• NHTSA ODI #11165895 (Chevrolet Equinox - similar platform) — ABS/ESC message duration varied from seconds to minutes.
  ❌ Tried (didn't work) Various online references indicated solutions were inconsistent.
  ✅ What actually fixed it A service center reported code C0045 and recommended replacing the left rear hub bearing assembly.

Model Year Variations Within This Range

• 2013-2017: The Traverse received a facelift for the 2013 model year, which included cosmetic and interior updates. However, the underlying GM Lambda platform, suspension, and ABS components related to this code remained largely the same through 2017. Part compatibility is generally high across the entire 2009-2017 generation for this specific repair.

Diagnostic Flowchart

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For this repair, the only part where a used component might be considered is the wiring pigtail connector, provided it is in excellent condition with no corrosion or brittle wires. Due to the high failure rate and difficulty in assessing remaining life, used sensors and wheel hubs are strongly discouraged.

Donor-vehicle mileage cap: roughly under 100000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a wiring pigtail, inspect for any green or white corrosion inside the connector.
• Check for flexible, non-brittle insulation on the wires.
• Ensure the locking tab is intact and functional.

Aftermarket brands forum-validated for this vehicle:

• For wheel hub assemblies: Timken, MOOG, SKF, and ACDelco (OEM) are consistently recommended by professionals and owners for their durability and quality control.
• For wheel speed sensors: Delphi, ACDelco (OEM), and Standard Motor Products (SMP) are reliable choices.

Brands owners have reported issues with on this vehicle:

• Unnamed, 'white box' or suspiciously cheap wheel hub assemblies and sensors from online marketplaces. These often use lower-quality bearings and seals that fail prematurely, sometimes causing the same code to return within a short period.

Real Owner Stories

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

Related OBD-II Codes

• C0050 — This is the companion code for the Right Rear Wheel Speed Sensor. The common causes on the Traverse—a failed magnetic encoder ring on the hub, a seized sensor, or wiring issues—are identical for both rear wheels. TSB PI0934 often addresses both C0045 and C0050.
• C0035 — This code points to the Left Front Wheel Speed Sensor. The failure mechanisms, especially the tendency for the magnetic ring on the hub assembly to delaminate due to rust, are common to all four wheels on this platform.
• C0040 — This code points to the Right Front Wheel Speed Sensor. It is frequently caused by the same issues as C0045, such as a cracked magnetic ring on the hub or a damaged wiring pigtail.
• C0245 — Wheel Speed Sensor Frequency Error. This is a more generic ABS code that can be set when the control module detects an irrational or erratic signal from a sensor, which directly aligns with the described symptoms of a failing sensor or magnetic ring on the Traverse.

Frequently Asked Questions