Brake pads light - Page 2

Rsnail · 18th March 2017, 23:22

Guys with all of this I'm trying to get to the point that I don't know what the problem really is, the pads look almost like new, and the sensors too, took them out, and I can't see nothing worn on them, maybe I'm not looking in the right place...

SD1too · 19th March 2017, 07:06

Quote:

Originally Posted by Rsnail

... the pads look almost like new, and the sensors too, took them out, and I can't see nothing worn on them...

Get a multimeter and check for an open circuit in the sensor circuit. Start at the blue connector which is beside the suspension strut top mounting at the front and easily located at the rear.

Simon

HarryM1BYT · 19th March 2017, 09:09

Quote:

Originally Posted by Rsnail

3. Can I find out if the front ones or rear ones are worn by shorting the small tip of the sensor that goes into the pad with a paper clip?

It is very crude device - a single circuit which passes from the ECU, through front, then rear, then either back to the ECU or to ground. The sensor is nothing more than a loop of wire pushed into a drilling in the pad. If continuity is broken, by either the pad wearing, or a poor connection - the light comes on.

Shorting the pins on a socket, will bypass that sensor position. Unless there is a break in the wiring, shorting each sensor out - should put the light out.

The pad wear indicator is of dubious value. It only checks one pad of the pair and only on the off-side disks (2 of the 8 pads). It is possible for pads to wear very unevenly, leaving the sensor pads like new and the others down to the metal backing.

raykay · 19th March 2017, 09:23

The circuit is from the instrument pack, to and through the front sensor, then to and through the rear sensor, and then to Earth. Any break in the circuit will switch on the warning light.

HarryM1BYT · 19th March 2017, 09:27

Quote:

Originally Posted by SD1too

Get a multimeter and check for an open circuit in the sensor circuit. Start at the blue connector which is beside the suspension strut top mounting at the front and easily located at the rear.

Simon

The blue plug is for the ABS sensors, black is for pad wear...

SD1too · 19th March 2017, 20:14

Quote:

Originally Posted by HarryM1BYT

The blue plug is for the ABS sensors, black is for pad wear...

Thank you for the correction Harry. You can guess what I've been working on recently!

Simon

Rsnail · 20th March 2017, 04:01

Can you please tell me how to short the sensors out? I took them out, they look like new, took the metal clip around them down, same thing, all looks untouched, is there a certain place where they wear out or how does this work? Maybe I'm not looking in the right place, as far as I've read, when the pad starts to wear, the sensor wears along with it too, or does only the pad start to wear and that indeed breaks the continuity of the circuit and thus the error starts showing up? Thanks.

Mike Noc · 20th March 2017, 09:35

The tip of the sensor wears through and breaks the circuit, bringing the lamp on.

You can test the sensors for continuity with a meter, or a bulb and 12v supply if you like, or you can short the two pins in the plug connection on the car. Do each plug in turn and that will help narrow down the fault if it is in the car wiring.

HarryM1BYT · 20th March 2017, 21:21

Quote:

Originally Posted by Rsnail

Can you please tell me how to short the sensors out? I took them out, they look like new, took the metal clip around them down, same thing, all looks untouched, is there a certain place where they wear out or how does this work? Maybe I'm not looking in the right place, as far as I've read, when the pad starts to wear, the sensor wears along with it too, or does only the pad start to wear and that indeed breaks the continuity of the circuit and thus the error starts showing up? Thanks.

It is just a loop in and out of the pad, of thin wire, close to the metal base of the pad. Once the pad wears down to the loop, it breaks the loop and the light comes on. A useful bit of test kit would be two old sensors from a worn out pad, with the two wire ends just shorted, so you can plug them in in place of the suspect sensors. If all is well with the rest of the wiring - the light should then go out immediately. You could instead, simply use a pair of new pads complete with sensors, just plugged into the black sockets.

Or even link the two pins of the black socket at a pinch.

Jim Jamieson · 20th March 2017, 21:30

Brake pads sensors are useless IMO

On my last three cars I've looped them out. It's a simple job, just unplug the sensor, cut the wires short of the plug, bare both ends and solder them together then either tape the bare end up or use heat shrink.

BTW on my Jaguar XF the brake pad indicator came on when I had approx 50% of pad wear left. Mind you my local Jaguar Stealer said they were worn 90% six months earlier.

19th March 2017, 09:23	#14
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 pack, to and through the front sensor, then to and through the rear sensor, and then to Earth. Any break in the circuit will switch on the warning light. Last edited by raykay; 19th March 2017 at 09:26..

18th March 2017, 23:22	#11
Rsnail Gets stuck in Rover 75 Saloon Join Date: May 2015 Location: Essen (Oldenburg), Germany Posts: 626 Thanks: 59 Thanked 30 Times in 28 Posts	Guys with all of this I'm trying to get to the point that I don't know what the problem really is, the pads look almost like new, and the sensors too, took them out, and I can't see nothing worn on them, maybe I'm not looking in the right place...

20th March 2017, 04:01	#17
Rsnail Gets stuck in Rover 75 Saloon Join Date: May 2015 Location: Essen (Oldenburg), Germany Posts: 626 Thanks: 59 Thanked 30 Times in 28 Posts	Can you please tell me how to short the sensors out? I took them out, they look like new, took the metal clip around them down, same thing, all looks untouched, is there a certain place where they wear out or how does this work? Maybe I'm not looking in the right place, as far as I've read, when the pad starts to wear, the sensor wears along with it too, or does only the pad start to wear and that indeed breaks the continuity of the circuit and thus the error starts showing up? Thanks.

20th March 2017, 09:35	#18
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,547 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	The tip of the sensor wears through and breaks the circuit, bringing the lamp on. You can test the sensors for continuity with a meter, or a bulb and 12v supply if you like, or you can short the two pins in the plug connection on the car. Do each plug in turn and that will help narrow down the fault if it is in the car wiring.

20th March 2017, 21:30	#20
Jim Jamieson This is my second home Rover less ! Join Date: Jun 2011 Location: Tarbolton Posts: 3,442 Thanks: 393 Thanked 888 Times in 542 Posts	Brake pads sensors are useless IMO On my last three cars I've looped them out. It's a simple job, just unplug the sensor, cut the wires short of the plug, bare both ends and solder them together then either tape the bare end up or use heat shrink. BTW on my Jaguar XF the brake pad indicator came on when I had approx 50% of pad wear left. Mind you my local Jaguar Stealer said they were worn 90% six months earlier.