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View Full Version : Persistant "Brake Linings" warning



mamilapon
06-18-2008, 09:28 PM
Boys and girls, Ive got new pads and sensors all round, still get the warning as soon as I turn the key! Inspected both sensors, all good, properly installed. What could it be? Search unsuccessful

bmwrp8
06-18-2008, 10:34 PM
same problem here:(

Barney Paull-Edwards
06-19-2008, 01:22 AM
Did you remember the tiny metal spring clip that holds the sensor to the pad?? Also clean the connectors to the car carefully to get good contacts and don`t force them, they will align with a raised sector so look and be careful! I used to disconnect the battery briefly to reset but it was not needed, maybe it might be for you??

bimmo_2007
06-19-2008, 09:44 AM
"Brake Linings" always means the circuit of the pad sensor is shorted, so you have to check the metal clips, the sensor itself & the wire. sometimes old sensors would work fine.

Tiger
06-19-2008, 10:07 AM
You have to double check the sensor... it could be bad or the wire too short that it pops off. I bought an aftermarket one and it was way too short. I also reused the old one that one day, the sign popped up... I then spliced the new sensor to the old wire so it is long enough and the sign went away.

Sensor do go bad on BMW. Use mulimeter to confirm there is good continuity.

whiskychaser
06-19-2008, 11:09 AM
If you get continuity through the sensors, disconnect them in turn and jumper the wiring back to find out which one ditches the message. If it stays on look for frayed wiring, especially round the front struts

mamilapon
06-19-2008, 05:04 PM
Shall do

shogun
06-19-2008, 05:42 PM
Switch ignition on, do not start the car, leave ignition on for 60 seconds, maybe it is gone. Provided it is connected correctly. Once read that, not sure if it works though.

Kibokojoe
07-21-2008, 09:55 PM
When I had problems the sensors looked good but the front sensor had a broken wire. I unplugged the sensors one at a time and short circuited them. This removed the error. I then replaced the bad sensor with a new sensor. This is a simple closed circuit if there is a break you get an error code. Anyway that is my understanding

attack eagle
07-22-2008, 01:52 AM
"Brake Linings" always means the circuit of the pad sensor is NOT shorted, so you have to check the metal clips, the sensor itself & the wire. sometimes old sensors would work fine.

sensor is continuous if good, open if bad.

ILoveMPower
10-02-2008, 08:47 AM
Have been having this problem also for the last couple years, I always assumed it was the line grounding out somewhere.

How do you test the sensor for continuity? Will a test light work fine? Also, are there any other spots common for fraying besides the front struts?

whiskychaser
10-02-2008, 09:19 AM
Have been having this problem also for the last couple years, I always assumed it was the line grounding out somewhere.

How do you test the sensor for continuity? Will a test light work fine? Also, are there any other spots common for fraying besides the front struts?

Bulb and battery method is fine-all you are looking to confirm is that the circuit is complete. Just disconnect at the plug and put a probe on each of the terminals of the yellow lead. Bulb should light. If it doesnt, yellow wire or sensor are at fault. The thin yellow covered wires that go to the sensors could fail - mine did on one of the rears. Didnt look frayed but had broken inside somewhere. If it does light, you are looking for a break in the wiring going the other way. More likely at the front near the struts as the wiring moves with the angle of the wheels. HTH

Tiger
10-02-2008, 09:37 AM
Just replace the sensor... it is that simple. You can test if that is problem by simply bypassing the sensor... stick a wire in both hole and tight... and if the warning sign go away, that is it.

Factory skinny wire sensor break so easily.

Kibokojoe
10-02-2008, 01:41 PM
Brake sensor is a simple loop. Unplug sensor and check continuity across the two wires. If you have a light the sensor is good. No light sensor is bad.

attack eagle
10-02-2008, 07:00 PM
continuity requires a DMM

Kibokojoe
10-02-2008, 08:27 PM
Sensor is really just a piece of wire. Continuity can be tested using a simple meter on ohms setting or with a couple pieces of wire, a bulb and a battery.
http://i273.photobucket.com/albums/jj225/kibokojoe/continuity.jpg
Have been having this problem also for the last couple years, I always assumed it was the line grounding out somewhere.

How do you test the sensor for continuity? Will a test light work fine? Also, are there any other spots common for fraying besides the front struts?

632 Regal
10-02-2008, 08:45 PM
I posted this about 10 times, trace the wire in the front where it goes through the fenderwell and up. There is a tendancy for it to rub through the insulation. If you doubt the sensors twist the wires together and then do your testing through the fenderwell.