Left Rear Wheel Speed Sensor Circuit
The C0045 code means the vehicle's onboard diagnostic system has detected: Left Rear Wheel Speed Sensor Circuit. This is a critical severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $100 - $300 (parts and labor)
Basic scanners cannot read ABS codes. BlueDriver reads all systems including ABS, SRS, and transmission through your phone.
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
Basic scanners cannot read ABS codes. This one reads all four systems so you know exactly which sensor failed.
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
Common Symptoms
- ABS warning light illuminated
- Traction control light on
- Rear ABS not functioning
- Stability control system disabled
- Cruise control may not engage
Probable Causes (Ranked by Likelihood)
- Defective left rear wheel speed sensor Very High
- Corroded or broken wiring at the rear axle High
- Damaged tone ring on rear axle or hub Moderate
- Sensor connector contaminated with water or road salt Moderate
- ABS control module malfunction Low
Step-by-Step Diagnostic Procedure
-
Pull codes and check freeze frame data for the affected wheel
-
Inspect left rear wheel speed sensor wiring for chafing or breaks along the axle
-
Test sensor output with a multimeter or oscilloscope
-
Spin the left rear wheel by hand and watch live data for signal output
-
Inspect the tone ring behind the brake rotor for damage
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
Why do rear wheel speed sensors fail more often?
Rear wheel speed sensors are more exposed to road debris, water, and salt spray. On trucks and SUVs, the wiring runs along the frame and axle where it is vulnerable to damage from rocks and corrosion.
Can a bad rear wheel speed sensor affect my transmission?
Yes. Some vehicles use wheel speed sensor data for transmission shift points. A faulty sensor can cause harsh or erratic shifting, especially in vehicles with electronically controlled automatic transmissions.
How do I test a wheel speed sensor?
You can measure resistance across the sensor terminals with a multimeter -- most sensors read between 1000 and 2500 ohms. You can also use a scan tool to monitor live wheel speed data while spinning the wheel by hand to verify signal output.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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:
See All Codes & Fixes for Your Vehicle
Explore More
Was this helpful?
Share carcodefinder.com with a friend who needs to decode their check engine light.