C0040 — Right Front Wheel Speed Sensor Circuit
High SeverityAt a Glance
What It Means
The right front wheel speed sensor circuit has a fault.
System
Brakes — ABS
Can I Drive?
Not recommended — risk of further damage.
Severity
High
Symptoms
- ABS warning light illuminated
- Traction control light on
- ABS may not function
- Possible false ABS activation
Common Causes
How We Diagnose C0040
Scan & Verify
Confirm C0040 and check for related codes that may share a root cause.
Live Data Review
Pull real-time sensor data to isolate whether the fault is electrical, mechanical, or software-related.
Component Test
Perform targeted tests on the specific circuit or component flagged by the code.
Root Cause Repair
Repair or replace only what is confirmed faulty — no parts-swapping guesswork.
Verify & Clear
Clear the code, perform a drive cycle, and confirm the monitor passes before returning the vehicle.
Related Services
Frequently Asked
Will code C0040 clear itself?
OBD-II codes do not clear themselves. The underlying fault must be repaired and the monitor must pass during a drive cycle before the light extinguishes.
Can I pass an Arizona emissions test with C0040 active?
No. Any active check engine light is an automatic emissions test failure in Arizona. The code must be resolved and the relevant monitor must complete before testing.
How long does a diagnostic take?
Most diagnostic appointments at Apex take 45–90 minutes. Complex electrical faults may require additional time for circuit testing.