popdemonic

sometimes when i start the engine,the brake pad wear will come on.or when i turn the wheel full lock and hit the brake then the light will come on.the mechanic said the wires is bad.it also happen on his Audi 100.any idea?

David Weinberger

Did you check to make sure the connection is good? Sounds like a loose connection if it happens when you turn the wheel to lock.....

-David

popdemonic

yep.i already check it.

popdemonic

it's intermittent.how can i check the wires?

David Weinberger

I'm scratching my head... The warning light comes on when the circuit is completed, when the pad is worn enough that the sensor touches the rotor. Either a bad sensor, grounding through the shoe to the caliper, or the wires are shorting out (frayed wire any where?)...

kinderutz

just bypass the wires and they won't come on again...make sure you check your pads once in a while

SchwarzS6

There is a wire in the pad that completes the circuit. When the pad gets very thin the wire wears through and the connection is broken. Quite a simple systems except for the fact that:

1. Most after market pads don't have the wires
2. The connectors are in a filthy dirty spot and the contacts corrode.
3. A lot of mechanics don't know how to disconnect the connector so they pull and wiggle and break the connector shell, after which it won't seal properly.

If the connector shell and rubber boot are in good shape you can try cleaning the contacts with some spray contact cleaner and then mate and demate the connetor a few times. If the shell is cracked the connector may not be staying together properly, in that case clean the contacts, mate the plug and wrap with electrical tape. If the wire is damaged you may need a new cable that goes from the connector to the engine bay harness.

Or you can do what many on this forum have done, cut the wire near the fender liner and solder the two leads together. The light should never come on again (for that side anyway) but you wont have the wear sensor any more either. At least then you can buy aftermarket brake pads!

kday

<img src="http://pictureposter.audiworld.com/66084/brakewear.jpg">

cpt_proton

check if the wires are grounded Pop...I had the same problem

David Weinberger

I guess that makes sense, but I always thought it was the other way around.

I asked my friend at Teves, and he said the circuit is completed when the sensor touches the rotor, and that triggers something in the ECU which will keep the light on until reset. Of course that would be for current production sensors.

-David