Brake Pad Wear Sensor Circuit Malfunction
The C0145 code means the vehicle's onboard diagnostic system has detected: Brake Pad Wear Sensor Circuit Malfunction. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- easy
- Estimated cost
- $20 - $200 (parts and labor)
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Common Symptoms
- Brake pad wear warning light on
- Service brakes message on dashboard
- Warning light on despite new brake pads
- Brake pad indicator stays on after pad replacement
- Brake pad thickness display shows error
Probable Causes (Ranked by Likelihood)
- Worn brake pad wear sensor wire Very High
- Brake pad wear sensor not replaced with new pads High
- Corroded wear sensor connector Moderate
- Wiring fault to brake pad sensor Low
Step-by-Step Diagnostic Procedure
-
Visually inspect brake pad thickness
-
Check brake pad wear sensor wire for damage
-
Verify wear sensor was replaced during last brake service
-
Test sensor circuit continuity
-
Inspect sensor connector for corrosion
Frequently Asked Questions
What is a brake pad wear sensor?
It is a thin wire embedded in the brake pad that contacts the rotor when the pad wears to a minimum thickness, completing a circuit that triggers the dashboard warning light.
Do all vehicles have brake pad wear sensors?
No. They are primarily found on European vehicles like BMW, Mercedes-Benz, Audi, and Volkswagen. Most Japanese and American vehicles rely on a metal tab that produces a squealing sound instead.
Should wear sensors be replaced every time brake pads are changed?
Yes. Wear sensors are one-time-use components. Once the wire has been worn through by the rotor, it must be replaced with new pads to reset the warning system.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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