C0040 on GMC
Right Front Wheel Speed Sensor Circuit
C0040 on GMC vehicles indicates right front wheel speed sensor circuit. Au7o has documented this code across 2 GMC models — most commonly on Sierra 1500, Yukon XL. This is a brake/ABS-system code. The right front wheel speed sensor measures how fast that wheel is rotating and feeds that data to the anti-lock brake, traction control, and stability control systems. C0040 means the ABS module found an electrical problem in the right front wheel speed sensor circuit — for example an open circuit, a short, or a signal that is missing or out of range. You'll normally see the ABS and traction/stability lights come on, and those systems may shut off temporarily while your regular brakes keep working. Typical repair costs on GMC range from $150 to $1,500, depending on the specific model and root cause.
Common Causes of C0040
- •Failed right front wheel speed sensor
- •Damaged, corroded or unplugged sensor wiring/connector
- •Damaged or rust-clogged tone/reluctor ring
- •Excessive air gap between sensor and tone ring
- •Wheel bearing wear affecting an integrated sensor
- •Water intrusion or corrosion at the connector
- •Faulty ABS control module (less common)
C0040 on GMC by Model
GMC Sierra 1500(2 issues)
- Electronic Brake Control Module Failure2014-2023
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.
- Front Hub Bearing Assembly Failure Causing ABS Activation, Noise, and Wheel Play1999-2013
Front wheel hub bearing assemblies on Sierra 1500 trucks commonly wear out, especially on 4WD models and trucks used with larger tires or in rough conditions. Owners report humming or growling that changes with speed, looseness in the front wheel, and in some cases ABS warnings or low-speed ABS activation because the wheel speed sensor is integrated into the hub. This is a frequent repair item across both GMT800 and GMT900 generations.
GMC Yukon XL(1 issue)
- Front Hub Bearing and ABS Wheel Speed Sensor Corrosion Causing Unwanted ABS Activation2000-2006
GMT800 SUVs commonly develop corrosion under the front wheel speed sensors or wear in the hub bearing assembly, which alters the low-speed wheel speed signal. The result is unexpected ABS activation at parking-lot speeds, longer stopping distances, and a pulsating brake pedal even on dry pavement. GM documented this condition in service bulletins, and owners frequently report replacing hub assemblies to cure it.
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View C0040 across all makes →Frequently Asked Questions
What does C0040 mean on GMC?▼
C0040 stands for "Right Front Wheel Speed Sensor Circuit." This is a brake/ABS-system code. The right front wheel speed sensor measures how fast that wheel is rotating and feeds that data to the anti-lock brake, traction control, and stability control systems. C0040 means the ABS module found an electrical problem in the right front wheel speed sensor circuit — for example an open circuit, a short, or a signal that is missing or out of range. You'll normally see the ABS and traction/stability lights come on, and those systems may shut off temporarily while your regular brakes keep working. On GMC specifically, this code is documented across 2 models.
What causes C0040 on GMC vehicles?▼
Common causes on GMC: Failed right front wheel speed sensor, Damaged, corroded or unplugged sensor wiring/connector, Damaged or rust-clogged tone/reluctor ring, Excessive air gap between sensor and tone ring, Wheel bearing wear affecting an integrated sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix C0040 on a GMC?▼
Repair costs on GMC range from $150 to $1,500, depending on the specific model and root cause.
Which GMC models have C0040 documented?▼
Au7o has documented C0040 on 2 GMC models: Sierra 1500, Yukon XL.