After getting off the track yesterday, my "Service Break Wear" (brake wear sensor) light came on. It came on when I restarted the car after shutting it off in the pit.

I visually inspected all my pads and they all look have 8-10mm of meat left on them. I have noticed recently that my rotors on all 4 corners are worn and will definitely need to be replaced once I get through these pads.

Visual inspection on the sensors all appear fine (in place),

Questions:
1. Is there anything related to the worn rotors or the pronounced rotor edge lip that could have caused the sensor to wear through?
2. What about something heat related from track braking?
3. A faulty sensor that just decided to give it up at the end of my track work?

I wish the car would tell me which corner! That would save me some diag time and effort.

I think what I need to do is buy one front and one rear sensor and just plug them in to see which one eliminates the warning.

Any other suggestions, opinions, etc? I know I can just cut the wires close to the plugs and join them together to eliminate the light, but I prefer to run the car "as designed".

Thanks in advance for your replies.

 

The brake sensors are a simple wear loop attached to each brake pad. Once the pads wear down enough the sensor loop touches the rotor and wears through, breaking the circuit. Yes you will still have some pad left. It's just a sensor.

Take a look at each caliper for a wire running to the pads. Try and see which one has the wear. If possible, disconnect the wire and check for continuity with a multimeter. Since you were on the track, chances are it's one of the fronts.

Another option is to tie wrap the sensors up out of the way like this. It's still connected to the car, just not attached to the caliper/pads to wear down and throw a dashboard light. It's good if you swap pads often between track and street use.

 

Looks like one of the front sensors overheated and melted, burning thru the wire. I wouldn't have expected the sensors to be designed not to take a little heat (I wasn't on the track that long and wasn't doing any super crazy braking). I'm a little disappointed that they don't...maybe the previous owner used cheap non OEM sensors!

Do I need to have fresh pads whenever I go to the track??

 

As for the sensor, it is unusual for it to melt. How many track sessions are on them? It's possible that it was cracked when previously removed to change out pads. They do tend to get brittle from the heat. As for the pads, the rule of thumb is at least 50% remaining before track day. This of course assumes either OEM or a reputable pad. Hope this helps.

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Also check to make sure the rotors are installed correctly. There are vanes inside the rotor that should point towards the rear of the car when rolling forward. It has nothing to do with the drill pattern of the holes, just the vanes inside the rotor.

When I bought my car wholesale, the front calipers were brown with the L/R rotors reversed. A prior owner tracked the car with the rotors on backwards, causing abnormal overheating.