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JanDaMan

Brake pad warning light

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Occasionally my brake pad warning light comes on the dash, however in looking at my pads to me it looks like there is a great deal of pad left on all the wheels (sample photo attached). I took photos from the outside of the wheels, but I would suspect the inside pads would have somewhat equal wear as the outside pads, no?  Only other thing I see is maybe the rear emergency brake pads look a bit low, but I never use the emergency brake and I don't think they have sensors anyway. Any thoughts, maybe overly cautious sensor pads built on the Lambos? I will see if I can slip my iPhone to the inside of the wheels to see what the inside pads look like.

IMG_9875.JPG

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Sensors are just 2 wires that break their connection when their pad wears onto the rotors.  It’s not really even fair real sensors, like pressure transducers, to call them sensors since there’s nothing too them. But it doesn’t stop manufactures from calling it a sensor and charging a boat load for just 50 cents of wire. 

You’ll have to pull the wheels off to find which one has failed. A visual inspection should identify the bad one, otherwise a multimeter to check continuity at the “sensor’s” connector will tell you. The sensor pads can get brittle and break after a while or one may have fallen out of place and rubbed away to trigger the light.

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The sensors are pretty easy to swap; pair of needle nose will normally do it, and I'd strongly suspect there's an equivalent Audi part number that will probably get them into the $6-10 range.

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Thanks guys. It just occurred to me, being rather anal I tend to wipe down my wheels after a run and even do so with a microfiber to the inside of the wheels too. I am thinking maybe I hit a wire in doing so but will try and investigate further. The light is just occasional and so I figure no real big deal as long as my pads visually look thick as shown. Maybe at my next tire change I will have it looked into unless I see something in the mean time.

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Had something similar with Aventador, random pad warning lights that then disappeared , turned out to be a dodgy wiring connector, try disconnecting and give them a clean as a starting point 

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The sensors are wired in a loop, if the loop is broken the light comes on. Like whiteout said, check the pad sensors to make sure they are not worn thru and the connectors as per Topjay,  to make sure they are getting good contact.

On the pad side you can check the circuit with a multimeter to see if you have continuity.

Went thru that before I changed the pads, connector was not making good contact.

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The sensors are relatively useless, and love to wear through before the pad is anywhere near done.  There is an audi part if you really want them.  They have a boot connector that hooks into the car side but that's probably not the issue.  They use a very small gauge cable and if it wiggles or gets bumped too much over time, from shop folks / detailers messing with, or cleaning, the rotors, easy for it to start fraying off the "sensor", which is nothing more than pad-like material the sensor wire is routed through.  I bypassed mine and tied them off since I have my wheels off more than often enough to know when it's time for new pads.

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11 minutes ago, tpamurci said:

The sensors are relatively useless, and love to wear through before the pad is anywhere near done.  There is an audi part if you really want them.  They have a boot connector that hooks into the car side but that's probably not the issue.  They use a very small gauge cable and if it wiggles or gets bumped too much over time, from shop folks / detailers messing with, or cleaning, the rotors, easy for it to start fraying off the "sensor", which is nothing more than pad-like material the sensor wire is routed through.  I bypassed mine and tied them off since I have my wheels off more than often enough to know when it's time for new pads.

 

They are especially useless on cars that only get driven 100-1000 miles per year. You should have the wheels off changing brake fluid every couple of years anyway. 

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1 hour ago, MGufran said:

I think brake pad warning light is a great feature for those who can't check brake pad on a regular basis.

I don't think anyone is complaining about the feature. More complaining that it doesn't function nearly as well as it should, to be of benefit. 

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23 minutes ago, Old Guy Garage said:

Other than track use has anyone ever had them actually wear out given the miles they are driven? I just replaced a set with 2K miles for dust control and they were like brand new.

Only that guy in the UK that put 300k miles on his Murci by renting it out. For the rest of us, it’s useless.


You’re definitely  not doing a good job maintaining your exotic if you have to rely on a brake pad warning system.

Now for a soccer mon’s minivan, that’s a different story.

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Funny for me anyway the light isn't appearing anymore. Good idea though to have the sensors looked at when I do my next brake fluid change, I didn't know the wheels come off for that.

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20 hours ago, JanDaMan said:

Funny for me anyway the light isn't appearing anymore. Good idea though to have the sensors looked at when I do my next brake fluid change, I didn't know the wheels come off for that.

Dramatically easier to get to the inside caliper bleed nipple by just taking the wheels off, so typically they'd be off unless someone's working on the car that just enjoys pain lol.

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