C0045: How to Diagnose & Fix — Left Rear Wheel Speed Sensor Circuit
10 vehicles · 7 makes · $100-$1,500 repair
How to diagnose and fix C0045: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Ford Focus · 2000–2007
2000-2007 Ford Focus (1st-generation Mk1 and Mk1.5) suffer from repeated rear wheel bearing failures, often within months of replacement. One Focus Fanatics owner reported the left rear wheel bearing failing 4 times in 7 months. Root cause is missing or degraded inboard spindle seals that allow brake dust and water into the bearing race, plus alignment drift (excessive negative camber or toe) accelerating wear. Ford ran safety improvement campaign 01I017000 for 2000-2001 Focus cars in salt-belt states, replacing the rear wheel bearings and adding extra bearing seals free of charge until December 31, 2002, after earlier recall 00V303000 had dealers inspect the rear bearings and fit a retention cap because the left rear hub nut could loosen. Replacement requires the full hub assembly. The 2012-2018 Mk3 Focus has separate bearing issues with different root causes (not covered by this entry).
Common Symptoms
- Humming or growling noise from rear wheels that increases with speed
- Rumbling noise that changes pitch when turning (load shifts off bearing)
- Vibration felt through vehicle floor
- Uneven rear tire wear
- ABS warning light if bearing play affects wheel speed sensor
- Loose or wobbly feeling in rear end
- Grinding noise from rear at highway speeds
How to Fix
Replace the rear wheel bearing/hub assembly as a complete unit - the bearing is sealed and non-serviceable. RepairPal estimates $317-429 per side. When replacing, clean the knuckle bore thoroughly and apply anti-seize compound to prevent the new bearing from seizing in the housing (makes future replacement much easier). If the vehicle is in a salt-belt state, replace both rear bearings simultaneously - the other side will likely fail soon after.
Sources for this issue (3)
Chrysler 300 · 2011–2023
ABS control module suffers internal failures due to short circuits in main circuit board. Prevents proper ABS operation and stores fault codes. While regular braking functions, vehicle loses anti-lock capability, traction control, and stability control.
Common Symptoms
- ABS warning light constantly illuminated
- BAS warning light
- Traction control warning
- U0121 code (lost communication with ABS)
- No ABS function during hard braking
How to Fix
ABS module replacement or professional rebuild service. Check all wheel speed sensors and wiring before replacement. Many specialty shops offer rebuild for $300-500 with warranty. OEM module requires programming to VIN.
Sources for this issue (1)
GMC Sierra 1500 · 2014–2023
The electronic brake control module (EBCM) experiences failures causing ABS, traction control, and stability control systems to malfunction. Issues range from warning lights illuminating to complete system failures. The 2023 models have a specific recall for software that may fail to display a warning light when brake fluid loss occurs.
Common Symptoms
- ABS warning light illuminated
- Traction control and stability control warning lights
- Service Brake Assist message on dash
- ABS system activates unexpectedly or not at all
- Brake pedal feels different or spongy
- Multiple warning lights illuminate simultaneously
How to Fix
EBCM software reprogramming at dealer. EBCM replacement. Wheel speed sensor replacement if sensor-related. Check and repair wiring connections.
Sources for this issue (1)
Chevrolet Avalanche · 2002–2006
Jeep Grand Wagoneer · 2022–2024
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C0045 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does C0045 mean?
C0045 stands for "Left Rear Wheel Speed Sensor Circuit." This is a brake/ABS-system code. Each wheel has a speed sensor that tells the anti-lock brake (ABS), traction control, and stability systems how fast that wheel is turning. C0045 means the ABS module has detected an electrical problem in the circuit for the left rear wheel speed sensor — such as an open, short, or signal that's missing or out of range. As a result you'll typically see the ABS and traction/stability warning lights, and those safety features may be temporarily disabled even though your normal brakes still work.
What are the most common causes of C0045?
The most common causes of C0045 are: Failed left rear wheel speed sensor, Damaged, corroded or disconnected sensor wiring/connector, Damaged or contaminated tone/reluctor ring (rust, debris, missing teeth), Excessive air gap between sensor and tone ring, Wheel bearing wear affecting the sensor (on bearing-integrated sensors), Water intrusion or corrosion in the connector, Faulty ABS control module (less common). The specific cause varies by vehicle.
How much does it cost to fix C0045?
Repair costs for C0045 range from $100 to $1,500, depending on the vehicle and root cause.
Which vehicles are affected by C0045?
Au7o has documented C0045 across 10 vehicle models from 7 manufacturers: Chevrolet, Chrysler, Ford, GMC, Honda, Jeep, RAM.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.