Left Rear Wheel Speed Circuit Malfunction (GM)
The C0045 code means the vehicle's onboard diagnostic system has detected: Left Rear Wheel Speed Circuit Malfunction (GM). This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $100 - $600 (wheel-speed sensor or wiring most often; EBCM/pump work costs more)
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Common Symptoms
- ABS and/or traction control warning lights on
- ABS and stability assist may be disabled (base brakes still work)
- Possible false ABS activation at low speed with a failing wheel-speed sensor
Probable Causes (Ranked by Likelihood)
- Fault in the ABS/traction control component this code names (Left Rear Wheel Speed Circuit Malfunction) High
- Damaged wiring or a corroded connector in that circuit - road-splash zones corrode connectors High
- Failed related sensor or actuator Moderate
- Control module fault Low
Common Fixes by Vehicle
What techs usually find when diagnosing C0045 on specific vehicles — tap your vehicle for the fix and the exact part:
2007-2018 Chevrolet Silverado/GMC Sierra easy DIY
Left rear wheel speed sensor on GM trucks is mounted on the rear axle housing. Road debris and salt cause it to corrode into the housing. Use penetrating oil and let it soak before removal to avoid breaking the sensor in the bore. If it snaps off, you will need to drill and extract the remains. Replace with an ACDelco sensor for proper fit.
Labor: 30 min - 1 hour2007-2017 Chevrolet Tahoe/Suburban/Yukon easy (sensor), hard (reluctor ring) DIY
Rear sensors on the Tahoe/Yukon are also in the axle housing. Same corrosion issues as the trucks. Soak with PB Blaster for 15 minutes before attempting removal. Check the reluctor ring inside the differential for damage if the new sensor still throws codes -- axle removal required to inspect the ring, which makes this a shop job.
Labor: 30 min (sensor), 3+ hours (reluctor ring)2008-2017 Chevrolet Equinox/GMC Terrain moderate DIY
Rear wheel speed sensor on the Equinox is built into the rear wheel hub assembly. If the sensor fails, replace the entire rear hub. These are less prone to failure than the fronts but still common at 80-100K miles. Listen for a droning noise from the rear as an early sign of hub bearing wear. Torque the hub bolts to 85 ft-lbs.
Labor: 1-2 hoursFrequently Asked Questions
What does C0045 mean?
C0045 is a chassis code used primarily by GM vehicles: Left Rear Wheel Speed Circuit Malfunction. It concerns the ABS/traction control system.
Can I keep driving with C0045?
Base brakes keep working, but assume ABS and stability control are offline until repaired - allow longer stopping distances and drive gently, especially in rain or snow. Repair promptly.
Is C0045 the same on every make?
The decimal C0xxx range is dominated by GM's assignments (Chevrolet, GMC, Buick, Cadillac). Other makes may use this ID differently - if your vehicle is not a GM product, verify the meaning in your make's service information.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Read the code with a GM-capable scan tool and note the symptom byte/subcode if shown.
-
View live data for the named circuit (e.g. all four wheel speeds while rolling for wheel-speed codes).
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Inspect the circuit's wiring and connectors - chassis harnesses live in the splash zone and corrode first.
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Follow the GM pinpoint test for C0045 before replacing components.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
C0045 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
Commonly Affected Vehicles
- Chevrolet, GMC, Buick, Cadillac (GM chassis code range)
Related Codes
See All Codes & Fixes for Your Vehicle
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