Brake pad warning light will not go out.

Gary Poulton · 11th December 2015, 18:39

The sensor wires rubbed through on the rear wheel snd the pad wear lamp came on. I have now fitted a new rear sensor, the plug is clean and fitted properly, plenty of meat on both front and rear pads, but the light is still on. This is now an MOT failure in Norway. Any good ideas? I dont need the sensor to work, as I keep a good eye on my cars, just want the lamp to go out! the fron sensor looks ok, no chaffing of wires etc.

All help is better than no help!

Gary Poulton

iandux · 11th December 2015, 18:51

Hi Gary

I had something similar when changing the front pads earlier this year.

It seems to be that, once activated, the sensor needs changing. Don't know why, but after renewing the sensor lead, the problem disappeared.

Hope this helps

Ian D

trikey · 11th December 2015, 18:56

Just cut the wires near the plug, join them together, light out instantly

SD1too · 11th December 2015, 19:26

Quote:

Originally Posted by iandux

It seems to be that, once activated, the sensor needs changing. Don't know why ...

It's very simple Ian. The sensor is a loop of wire embedded in the brake pad friction material. This loop completes the electrical circuit which keeps the warning lamp off.

As the friction material wears, this loop comes into contact with the hard metal of the brake disc. Eventually the loop is eroded by the friction and the circuit is broken. The brake pad warning lamp then illuminates.

As the sensor is damaged it cannot be re-used, hence the need to buy a new one.

This is not the only piece of automotive technology which is not as complicated as the manufacturers would have us believe.

Simon

cb750chris · 11th December 2015, 19:41

Replacement sensors are cheap enough to buy, I have ordered some from here http://www.banggood.com/SOE100010-SO...p-1014262.html
Not tried them yet, but they look about right, and as described above they are so simple I don't have any works about giving them a try.

Gary Poulton · 12th December 2015, 09:22

I am aware of this, the problem started, I think, when the wires have rubbed on the wheel, breaking the circuit, I fitted a new sensor, making sure the plug was properly pluggee together, and light has stayed on, I assume and hope that I dont need to have it on T4 to reset it all? I have not rried to read any fault codes, nor have I checked wiring on the front sensor. Any good ideas.

iandux · 12th December 2015, 10:12

Quote:

Originally Posted by SD1too

It's very simple Ian. The sensor is a loop of wire embedded in the brake pad friction material. This loop completes the electrical circuit which keeps the warning lamp off.

As the friction material wears, this loop comes into contact with the hard metal of the brake disc. Eventually the loop is eroded by the friction and the circuit is broken. The brake pad warning lamp then illuminates.

As the sensor is damaged it cannot be re-used, hence the need to buy a new one.

This is not the only piece of automotive technology which is not as complicated as the manufacturers would have us believe.

Simon

Thanks, Simon

I was under the mistaken impression that the sensor operated when the friction material had worn down to the extent that the sensor came into contact with the disc, activating the light. Didn't realise that it worked by breaking, rather than completing a circuit.

SD1too · 12th December 2015, 10:46

Quote:

Originally Posted by Gary Poulton

... I fitted a new sensor, making sure the plug was properly pluggee together, and light has stayed on, I assume and hope that I dont need to have it on T4 to reset it all?

No Gary, you don't need T4. You must have a break or high resistance somewhere in the circuit, or the other sensor is triggering the warning lamp.

Simon

raykay · 12th December 2015, 10:56

The circuit is - from the instrument panel, through the front sensor, then through the rear sensor and then to Earth. As above, any break or high resistance in the circuit will switch on the warning light. Once the circuit is restored, the light will go out.

MangoMan · 12th December 2015, 11:33

Try this - you have to do this on BMW's so might have to do it with ours...

You have to reset the light by leaving the ignition switch on position #2 for about 30 sec. turn off the ignition and then start the engine up and see if it goes out.

11th December 2015, 18:39	#1
Gary Poulton Regular poster Rover 75 Join Date: Sep 2011 Location: Mosjøen Posts: 32 Thanks: 6 Thanked 0 Times in 0 Posts	Brake pad warning light will not go out. The sensor wires rubbed through on the rear wheel snd the pad wear lamp came on. I have now fitted a new rear sensor, the plug is clean and fitted properly, plenty of meat on both front and rear pads, but the light is still on. This is now an MOT failure in Norway. Any good ideas? I dont need the sensor to work, as I keep a good eye on my cars, just want the lamp to go out! the fron sensor looks ok, no chaffing of wires etc. All help is better than no help! Gary Poulton

11th December 2015, 18:56	#3
trikey Premium Trader Rover 75 Join Date: Nov 2010 Location: Devon Posts: 33,774 Thanks: 8,837 Thanked 14,831 Times in 8,030 Posts	Just cut the wires near the plug, join them together, light out instantly __________________ Lest we forget..

11th December 2015, 19:41	#5
cb750chris Trader Rover 75 Tourer Join Date: Apr 2011 Location: Portsmouth Posts: 849 Thanks: 201 Thanked 292 Times in 200 Posts	Replacement sensors are cheap enough to buy, I have ordered some from here http://www.banggood.com/SOE100010-SO...p-1014262.html Not tried them yet, but they look about right, and as described above they are so simple I don't have any works about giving them a try. __________________ Now offering T4 services in the Fareham area Replacement keys programmed / supplied / cut Diesel 135 upgrade available IPK virginisation and T4 matching available Sorry, due to a big change in home circumstances, I am unable to do any large jobs at present, but can still offer evening time diagnostics.

12th December 2015, 09:22	#6
Gary Poulton Regular poster Rover 75 Join Date: Sep 2011 Location: Mosjøen Posts: 32 Thanks: 6 Thanked 0 Times in 0 Posts	Thanks I am aware of this, the problem started, I think, when the wires have rubbed on the wheel, breaking the circuit, I fitted a new sensor, making sure the plug was properly pluggee together, and light has stayed on, I assume and hope that I dont need to have it on T4 to reset it all? I have not rried to read any fault codes, nor have I checked wiring on the front sensor. Any good ideas.

12th December 2015, 11:33	#10
MangoMan This is my second home Looking.... Join Date: Oct 2010 Location: England Posts: 10,911 Thanks: 862 Thanked 1,111 Times in 868 Posts	Try this - you have to do this on BMW's so might have to do it with ours... *You have to reset the light by leaving the ignition switch on position #2 for about 30 sec. turn off the ignition and then start the engine up and see if it goes out.* __________________ *Regards, Bill - (MangoMan).* (Member 00854) http://i1110.photobucket.com/albums/...d.jpg~original

11th December 2015, 18:51	#2
iandux Loves to post At last....75 Facelift Connie Join Date: Aug 2013 Location: Longridge Posts: 443 Thanks: 199 Thanked 117 Times in 70 Posts	Hi Gary I had something similar when changing the front pads earlier this year. It seems to be that, once activated, the sensor needs changing. Don't know why, but after renewing the sensor lead, the problem disappeared. Hope this helps Ian D __________________ A man is not a failure if he falls.....only if he refuses to get up again. This vehicle was the 96,129th 75 to run off the production line, out of 112,381 This vehicle was the 2,123rd 75 CDT Connoisseur SE (135) to be made out of 4,744 This vehicle was the 394th 75 in Firefrost Red (code: CEV) to be made out of 2,089 Firefrost Red 75s

12th December 2015, 10:56	#9
raykay I really should get out more....... Now Other Manufacturer Join Date: Nov 2006 Location: Co. Kerry Posts: 2,786 Thanks: 16 Thanked 310 Times in 283 Posts	The circuit is - from the instrument panel, through the front sensor, then through the rear sensor and then to Earth. As above, any break or high resistance in the circuit will switch on the warning light. Once the circuit is restored, the light will go out.