C0045 on 2008-2017 Buick Enclave: Left Rear Wheel Speed Sensor Circuit Causes and Fixes

What's Unique About the 2008-2017 Buick Enclave

The first-generation Buick Enclave and its GM Lambda platform siblings (Chevrolet Traverse, GMC Acadia, Saturn Outlook) are highly susceptible to issues with the magnetic encoder ring integrated into the wheel hub and bearing assembly. Unlike many other vehicles where the sensor itself is the most common failure point, on these SUVs, it's far more common for the exposed encoder ring to rust, crack, and break apart, especially in regions that use road salt. GM issued service bulletin PIC5428F acknowledging that ferrous metallic debris sticking to this magnetic ring can also cause the fault, sometimes allowing for a fix by simply cleaning it.

Symptoms You May Notice

• ABS warning light illuminated
• Traction Control warning light illuminated
• "Service StabiliTrak" or "Service Traction Control" message on the driver information center (DIC)
• A grinding or clicking noise from the wheels at low speeds if the hub bearing is also failing.
• In some cases, the transmission may exhibit hard or shuddering shifts, as the traction control system malfunction can influence transmission behavior.
• Cruise control may be disabled.

Most Likely Causes

1. Damaged or Corroded Magnetic Encoder Ring on Wheel Hub 🔴 High Probability The design integrates a magnetic ring into the inboard side of the wheel hub assembly, which is exposed to the elements. In areas with road salt and moisture (the "Salt Belt"), this ring is known to rust, swell, crack, and break apart, causing a loss of signal.
   How to confirm: After safely lifting the vehicle, remove the left rear wheel and visually inspect the dark, magnetic ring on the back of the hub assembly. Look for cracks, missing sections, or severe rust. Often, pieces of the ring will be visibly missing, or the entire ring will have delaminated from the hub.
   Typical fix: Replace the entire left rear wheel hub and bearing assembly. The encoder ring is not sold as a separate part. 🎬 See this overview of the rear hub bearing replacement process.
   Est. part cost: $150-$270
2. Metallic Debris on Magnetic Encoder Ring 🟡 Medium Probability The encoder ring is magnetic and can attract and accumulate ferrous metallic debris (rust particles, brake dust) from the road and brakes, disrupting the sensor's reading. This is well-documented in GM TSB PIC5428F.
   How to confirm: Visually inspect the magnetic encoder ring for any attached debris. It may look like a fine metallic paste or larger metal shavings stuck to the face of the ring.
   Typical fix: Carefully clean the debris from the face of the magnetic ring using a non-metallic brush and brake cleaner. TSB PIC5428F specifically cautions not to damage the bearing's outer seal during cleaning. If the code clears and stays off, no parts are needed.
   Est. part cost: $0
3. Faulty Left Rear Wheel Speed Sensor or Harness ⚪ Low Probability → Shop ABS Wheel Speed Sensor While less common than hub failure on this platform, the sensor and its wiring are still exposed to heat, vibration, and moisture. The harness connector can also become deformed or the terminals can lose tension, causing a poor connection.
   How to confirm: If the encoder ring is confirmed to be clean and intact, test the sensor. Use a scan tool that can graph live wheel speed data to see if the signal is dropping out. Check the wiring harness for chafing, especially where it might contact the transmission case. Inspect the connector pins for corrosion or damage.
   Typical fix: Replace the left rear wheel speed sensor and harness assembly. In some cases, repairing a damaged connector may be possible.
   Est. part cost: $20-$100

Rare But Worth Checking

• Faulty Electronic Brake Control Module (EBCM): → Shop ABS Control Module This is very rare. An EBCM failure typically triggers multiple wheel speed sensor codes or communication codes (like U-codes), not just a single one. This should only be considered after all other possibilities, including wiring continuity checks back to the module, have been exhaustively ruled out.

Diagnosis Steps

1. Connect an OBD-II scanner capable of reading ABS codes to confirm C0045 is the active or stored code. Note any symptom bytes, like '5A'.
2. Use the scanner's live data function to monitor all four wheel speeds while driving slowly in a straight line. Confirm that the left rear wheel speed signal is erratic, dropping to zero, or absent compared to the other three.
3. Safely raise and support the vehicle and remove the left rear wheel.
4. Visually inspect the magnetic encoder ring on the inboard side of the wheel hub assembly. Check for rust, cracks, missing chunks, or metallic debris stuck to its surface. This is the most critical step for this platform.
5. If significant debris is present, clean the ring thoroughly with a non-metallic brush and brake cleaner, being careful not to damage the bearing seal, and re-test.
6. If the ring is visibly damaged or missing sections, the wheel hub assembly must be replaced.
7. If the ring appears perfect, inspect the wheel speed sensor wiring harness for any signs of damage, chafing, or corrosion at the connector. Check for a secure connection. A corroded connector was the culprit in one documented GM repair.
🎬 Watch: A mechanic diagnoses a C0045 code on an Enclave.
8. If the ring and wiring are good, the wheel speed sensor itself is the next likely suspect. It can be tested for proper signal output with an oscilloscope or by checking for AC voltage while spinning the wheel.
9. After the repair, clear the codes with the scanner and perform a test drive to ensure the warning lights do not return. The lights may go out on their own after a few drive cycles if the fault is corrected.

Parts You'll Likely Need

• Rear Wheel Hub and Bearing Assembly (OEM #19434718 (ACDelco OE)) — This is the most common fix because the integrated magnetic encoder ring fails due to rust and corrosion, which is a well-documented issue on this platform.
  Trusted brands: ACDelco (OE and Advantage lines), MOOG (Part #513277), Timken (Part #HA590243), SKF
  OEM price range: $200-$270
  Aftermarket price range: $85-$220
• Rear ABS Wheel Speed Sensor (OEM #ALS1754) — This is replaced if the magnetic ring on the hub is confirmed to be in perfect condition, but the sensor's signal is still faulty.
  Trusted brands: ACDelco, Delphi, Holstein
  OEM price range: $55-$100
  Aftermarket price range: $20-$75

Related Codes That Often Appear With This One

• C0045-5A: This is a more specific version of the code, indicating 'Left Rear Wheel Speed Sensor Circuit Plausibility Failure', which strongly points to a problem with the signal quality from the encoder ring rather than a complete electrical open/short.

Technical Service Bulletins (TSBs) & Recalls

• PIC5428F: This series of GM Preliminary Information bulletins addresses codes C0035, C0040, C0045, and C0050 with symptom bytes 18, 5A, or 0F. It advises technicians to inspect for and clean ferrous metallic debris from the wheel bearing's magnetic encoder ring before replacing any parts. It explicitly states, 'In most cases the DTCs...can be repaired by removing and/or cleaning any accumulated debris'. The bulletin covers a wide range of GM vehicles from 2007-2017, including the Enclave and its platform mates.

Platform-Specific Known Issues

• A known issue on this platform is the premature failure of the rear wheel bearing's magnetic encoder ring due to corrosion, leading directly to ABS/StabiliTrak faults like C0045. This is especially prevalent in the Salt Belt states.
• The axle nut torque specification for the rear hub on 2008-2011 models is 151 ft-lbs (205 Nm).

Mechanic-Grade Diagnostic Values

• Active Sensor Voltage Supply (Key On) — expected: 12V DC reference on the Tan wire at the sensor connector.. Failure: Voltage significantly below 12V or absent indicates a wiring or EBCM issue.
• Active Sensor Signal (Oscilloscope) — expected: A clean square wave on the Orange wire at the sensor connector that increases in frequency as the wheel is spun.. Failure: A missing, noisy, or erratic waveform indicates a faulty sensor or a damaged magnetic encoder ring.
• Active Sensor AC Voltage Output (Multimeter) — expected: Greater than 100mV AC when spinning the wheel by hand; voltage should increase with speed.. Failure: No voltage or very low voltage suggests a failed sensor or damaged encoder ring.

Hidden / Shadow Codes Worth Checking

• C0045 0F: Indicates the wheel speed sensor circuit signal is erratic. This strongly points to a physically damaged or debris-covered magnetic encoder ring, or a wiring issue causing intermittent signal loss. (see via A professional scan tool capable of reading GM-specific symptom bytes, such as a GM GDS2.)
• C0045 18: Indicates the wheel speed sensor circuit has low signal amplitude. This suggests a weak signal from the sensor, which could be caused by an excessive air gap, internal sensor fault, or a partially damaged encoder ring. (see via A professional scan tool capable of reading GM-specific symptom bytes, such as a GM GDS2.)
• C0045 5A: Indicates a 'Plausibility Failure'. The EBCM is receiving a signal, but it is illogical compared to the other wheel speed sensors (e.g., it doesn't match when driving straight). This is the most common symptom byte for a broken encoder ring. (see via Most enhanced OBD-II scanners capable of reading ABS codes can see this common sub-code.)

Scan Tool Commands That Help

• GM GDS2 / Enhanced OBD-II Scanner: Live Data Graphing — This is the primary diagnostic step. Graph all four wheel speed sensors on the same screen and drive the vehicle. A faulty left rear sensor circuit will show the signal dropping to zero, lagging, or appearing erratic while the other three signals are smooth and consistent.
• Any ABS-capable Scanner: Clear Codes — After reading the code, clear it and see if it returns immediately with the key on (without driving). If it does, this indicates a 'hard fault' like an open/shorted wire or a completely failed sensor. If it only returns after driving, it's an intermittent fault, more typical of a cracked encoder ring or debris.

Wiring & Ground Locations

• Left Rear WSS Connector — At the left rear wheel, connecting the sensor pigtail to the main body harness.. This connector is a common point for corrosion and damage. On a 2012 Enclave, Pin 9 (Tan wire) is the 12V power feed, and Pin 10 (Orange wire) is the signal wire. These are the primary points for electrical testing.
• G103 (Potential EBCM Ground) — On some GM platforms, this is located at the left rear of the engine compartment on the cowl, above the brake booster.. A poor ground for the Electronic Brake Control Module (EBCM) can cause a variety of erratic ABS codes, including a false C0045. While rare, checking that the EBCM ground is clean and tight is a valid step if sensor, hub, and wiring tests are inconclusive.

Real Owner Repair Stories

• SSL Family Dad (YouTube) (Buick Enclave (2008-2017 generation)) — ABS, Stabilitrac, and Traction Control errors. Unwanted ABS engagement while driving.
  ❌ Tried (didn't work) Replacing the left rear wheel speed sensor.
  ✅ What actually fixed it Replacing the entire rear wheel hub and bearing assembly solved the problem, as the magnetic ring on the original bearing was the true cause of the 'implausible signal' code.
• Pine Hollow Auto Diagnostics (YouTube) (2012 Buick Enclave AWD) — "Service Stabilitrak" message, ABS and traction control lights on, code C0045-5A stored.
  ❌ Tried (didn't work) The diagnosis immediately focused on the signal quality, bypassing unnecessary part swaps.
  ✅ What actually fixed it An oscilloscope test on the sensor's signal wire showed an erratic waveform. Visual inspection confirmed the magnetic encoder ring on the back of the wheel hub was rusted and broken apart. Replacing the left rear wheel hub assembly fixed the issue.
• kz Guy 2 (YouTube) (2010 GMC Acadia (Lambda Platform sibling)) — ABS and traction light on, code C0045.
  ❌ Tried (didn't work) Diagnosis went straight to live data and visual inspection.
  ✅ What actually fixed it Using a scan tool to graph the wheel speeds showed the left rear signal dropping out. A visual inspection of the hub revealed a visible break in the magnetic tone ring. Replacing the hub assembly resolved the code.

When the Usual Fixes Don't Work

• In a small number of cases found on forums, after replacing both the sensor and the hub assembly, the code C0045 persisted. The ultimate cause was a break or corrosion in the wiring harness between the wheel well and the EBCM. This emphasizes that if the two most common causes do not resolve the issue, a full circuit continuity and integrity test back to the control module is required.

OEM Part Supersession History

• 15918787, 15941790, 22756832, 25784448, 25848366, 85152279 → 19434718 — Part consolidation and potential design updates over the vehicle's production run.

Model Year Variations Within This Range

• 2008-2017: While the hub and sensor parts are consistent across the generation, the rear axle nut torque spec is 151 ft-lbs (205 Nm). Do not confuse this with the front axle nut spec which is higher. Over-torquing can damage the new bearing.

Diagnostic Flowchart

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used part is generally NOT recommended for this repair. However, if on a tight budget, a used wheel speed sensor harness/pigtail from a low-mileage donor vehicle from a dry climate could be a viable option if only the connector is damaged.

Donor-vehicle mileage cap: roughly under 60000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a hub: Absolutely no visible rust or cracks on the magnetic encoder ring. Spin the bearing by hand; it must be perfectly smooth with zero play or noise.
• For a sensor/harness: The plastic connector should not be brittle, and the pins must be perfectly clean and straight. The wiring insulation should be flexible, not cracked.

OEM-only on this vehicle (don't cheap out):

• Electronic Brake Control Module (EBCM). If the module is diagnosed as faulty, a new or professionally remanufactured unit from a reputable source is strongly advised over a typical junkyard part.

Aftermarket brands forum-validated for this vehicle:

• For the wheel hub assembly: Timken, MOOG, SKF, and ACDelco (GM's own brand) are consistently cited as high-quality, reliable choices.

Brands owners have reported issues with on this vehicle:

• Unbranded 'white-box' hub assemblies from online marketplaces. These often use lower quality bearings and seals that can fail prematurely, forcing you to do the job again.

Real Owner Stories

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

Related OBD-II Codes

• C0035 — Right Front Wheel Speed Sensor Circuit. This code is frequently caused by the exact same failure mechanism as C0045 (a damaged or debris-covered magnetic encoder ring) but on the right front wheel. Both are covered under the same GM TSB PIC5428F.
• C0040 — Right Rear Wheel Speed Sensor Circuit. This is the companion code for the opposite rear wheel. It is often triggered by the same common cause on this platform: corrosion or damage to the magnetic encoder ring on the right rear hub assembly.
• C0050 — Left Front Wheel Speed Sensor Circuit. Like C0035 and C0040, this code points to a different wheel but is related because the underlying cause—failure of the hub's integrated magnetic ring—is a known issue on all four corners of this vehicle platform, as noted in TSB PIC5428F.

Frequently Asked Questions