C004A code meaning
Brake Lining Wear Sensor
What C004A means
Covers the brake lining (pad) wear sensor circuit, which warns the driver when friction material is worn to its limit. Electronic wear sensors use a loop embedded in the pad that the disc contacts and opens, or a wear-indicator circuit, as the lining wears down; the module reports pad wear and may store this code for an open, shorted or implausible sensor circuit as well as for a genuine worn-pad signal. It is an advisory function rather than a safety-critical control loss: braking and ABS continue, but the driver is told to inspect or replace the pads. The code can appear after pad replacement if the sensor was not renewed or reconnected. Delphi describes both the single loop and two-stage sensors with two resistor circuits. No manufacturer documents this code publicly.
C004A at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C004A
- Brake pad wear warning message
- Warning lamp on
- Possible squeal from a mechanical indicator
Common causes of C004A
- Most likelyBrake pads worn to the sensor limit
- PossibleOpen or shorted wear sensor circuit
- Less likelySensor not renewed after pad change
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake pads
What each part of C004A means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4A | The exact fault in that area. |
What to do next
- Note C004A and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C004A
What does C004A mean?
C004A means "Brake Lining Wear Sensor". Covers the brake lining (pad) wear sensor circuit, which warns the driver when friction material is worn to its limit. It is a generic code, so it means the same on every make.
Is it safe to drive with C004A?
C004A does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will C004A fail an emissions test?
C004A is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C004A to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will C004A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.