Brake pad warning light issues

**20vcqdriver** · 27-01-2014,09:06 PM

Anyone had this issue..
Ever since buying my Le MAns A6 12 months ago, I have had the brake pads low warning light on the dash so replaced the front pads shortly after buying it with no affect and not surprised as old ones not worn right down. So just got round to sorting the rear discs and pads that needed sorting and still no difference. Any ideas where to go next...
Thanks
Is it possible to take this out of circuit using vcds

**Guest 2** · 27-01-2014,09:20 PM

Sensors only on the front, how did the plug look? Any broken wires?

Sensor reads off the inside pad behind the disc.

**20vcqdriver** · 28-01-2014,11:04 AM

This is what I thought so during the front pad change I measured the resistance across the loom plug and got a reading so no open circuit/ broken wires in the loom and reading was the same for both sides yet it still comes up on the dash as soon as you press the starter. Even shorted out the terminals on both sides to replicate the pad wear wire but no change hence why I thought the servo motors for the back had a limit switch but it appears not. Was hoping I could dissable the function in VCDS somewhere. Would it be an MOT fail!!!!

**furfurfur** · 29-01-2014,02:35 PM

I know that it's not an MOT fail, as my car went through it's MOT OK with the Brake Pad Low lamp on.

However, based on your troubleshooting can you be certain that it's definitely the brake pad low sensor? Could it be the brake fluid sensor? Try topping up the brake fluid, or inspecting the brake fluid switch.

**20vcqdriver** · 19-03-2014,12:13 PM

Still having this issue and car failed MOT because of it which is nuts as pads still as new front and back. There must be a way of dissabling in VCDS. Any VCDS experts out there.Audi telling me it might be a loom or dash controller fault and 'could' cost upto £1000 just to put a flaming pointless dash warning out, will sell car first.......

**furfurfur** · 19-03-2014,12:27 PM

Originally Posted by 20vcqdriver

Still having this issue and car failed MOT because of it which is nuts as pads still as new front and back. There must be a way of dissabling in VCDS. Any VCDS experts out there.Audi telling me it might be a loom or dash controller fault and 'could' cost upto £1000 just to put a flaming pointless dash warning out, will sell car first.......

That sucks, sorry to hear your MOT place is so picky! Are you 100% sure it's the brake pad warning icon and not something else more serious to do with brakes? If it's just the wear sensor triggering it, there must be a break in the cable somewhere. If it were my car I'd find the wiring diagram, trace the sensor cables right up to the ECU and connect them together as close to the ECU as possible, isolating the faulty cabling completely.

Any decent auto electrical place should be able to do this for you.

**Guest 2** · 19-03-2014,12:28 PM

Brake pad light won't fail MOT in NI anyway, but obviously it'll fail if there is no friction material left on them.

**20vcqdriver** · 19-03-2014,12:39 PM

Defo pad warning because as well as the symbol at the top of the display it initially also brings up the low pads message. Both cables to the struts are not open circuit and show a resistance that is the same both sides, hence loom must be OK, which is why I fear it might be a dodgy input to the controller and it must be possible to disable it in VCDS or give it a 'forced ' OK signal.
Its nuts and why I prefer my Cq as far less to go wrong and no daft expensive controllers to go wrong....
I am also an Electrical Engineer so I'm going to either sort myself or sell the heap of scrap. Also peeved off with other issues with it such as the unbelievably sloppy throttle response amongst others

**furfurfur** · 19-03-2014,12:51 PM

Originally Posted by 20vcqdriver

Defo pad warning because as well as the symbol at the top of the display it initially also brings up the low pads message. Both cables to the struts are not open circuit and show a resistance that is the same both sides, hence loom must be OK, which is why I fear it might be a dodgy input to the controller and it must be possible to disable it in VCDS or give it a 'forced ' OK signal.

I know it's not possible to fix this with VCDS. It's only possible to see/modify things that the Audi engineers have decided to expose through the interface. They certainly wouldn't allow you to override a brake related warning light!

I believe the brake wear sensor is just a wire that breaks when it gets worn out, so it's logical to me that it could be thought of one continuos wire that comes out of the ECU, through the brake pad, and back in again. Are you testing the loom with or without the brake pads connected? Depending on where you are testing the continuity, it would certainly be possible to get good continuity if the break in the wire is "upstream" of where you're testing. Current would flow through the intact brake pad no problem

I'd use the wiring diagram to identify the ECU pins involved, pull the loom at the ECU and check for continuty there. If THAT is OK, then the ECU could be faulty, maybe a dry joint or something? Of course, by ECU, I mean whatever control module the brake sensor connects into. May not be the ECU as such.

Do you have access to the wiring diagrams?

**furfurfur** · 19-03-2014,01:04 PM

I was bored so had a look at the diagram for my car (2008 Le Mans Saloon), i'd be surprised if yours is different.

It's a very simple circuit, and as I suspected, is basically one long wire that comes out of the "Dash Panel Insert", through both brake pads, and to Earth.

The wire originates at the dash panel insert, connector T32 (described as a grey 32 pin connector on dash panel insert) pin number 26 - a yellow cable.

I'd hardwire that to Earth and see what happens...