Question about bypassing brake linings sensor

[repenttokyo]

So I got the brake linings message, and rather than replace the sensors I wanted to bypass them. I had read that they were a simple circuit that could be shorted to make the message go away.

I cut the wire between the pad connection and the part of the sensor that plugs into the thick plug mounted on the caliper itself. I took the two strands of wire there and looped them together. I did this front and back. However, I still have the brake linings message.

Am I doing it wrong? Any help would be appreciated.

[whiskychaser]

So I got the brake linings message, and rather than replace the sensors I wanted to bypass them. I had read that they were a simple circuit that could be shorted to make the message go away.

I cut the wire between the pad connection and the part of the sensor that plugs into the thick plug mounted on the caliper itself. I took the two strands of wire there and looped them together. I did this front and back. However, I still have the brake linings message.

Am I doing it wrong? Any help would be appreciated.
I dont think you are doing it wrong at all. I think its likely there is a break in the wiring before the cut you made. Try jumpering the wires at the plugs. If that doesnt work, trace the wiring back. I'd pay particular attention to the wiring where it hides behind the front suspension - it can chafe against the leg and break the circuit there.

[bubba966]

There's a reset you need to do on the brake lining message to get it to go away after it's come up. I don't recall it exactly as I've not done it yet. But it has to do with turning the ignition on to position 1 or 2 (don't remember which) and leaving it there for a minute or so. Then I think you turn the ignition off and it shouldn't come on again.

[Tiger]

There are two sensors... front driver and rear passenger. You need to find out which one triggered that message. Once you found out, then splice it. If it doesn't work at where you spliced it, then there is still a wire break so cut back closer to the plug and splice it again.

Sensors are so cheap why not just buy a new one and put it in. Chances are if you bypassed it and it start to grind into your rotors, you are gonna be out of money even more unless you like those cheap rotors.

[repenttokyo]

There are two sensors... front driver and rear passenger. You need to find out which one triggered that message. Once you found out, then splice it. If it doesn't work at where you spliced it, then there is still a wire break so cut back closer to the plug and splice it again.

Sensors are so cheap why not just buy a new one and put it in. Chances are if you bypassed it and it start to grind into your rotors, you are gonna be out of money even more unless you like those cheap rotors.

both are spliced.

it's not a question of money, it's a question of not needing a sensor like this that can just suddenly stop working properly....my brake pads are fine. i've got hawk pads and brembo rotors, so it's not like i'm trying to save pennies here. i know when my pads need to be replaced and I don't need a defective nanny to tell me when it thinks they should be changed :(

the rear wheel bearing was replaced just before I started getting this message, which makes me think that the sensor was somehow damaged.

[repenttokyo]

I dont think you are doing it wrong at all. I think its likely there is a break in the wiring before the cut you made. Try jumpering the wires at the plugs. If that doesnt work, trace the wiring back. I'd pay particular attention to the wiring where it hides behind the front suspension - it can chafe against the leg and break the circuit there.

i'm a bit nervous about cutting into the wiring prior to the plugs - the sleeve is very thick, and if I'm wrong looks like it could be difficult to replace.

[repenttokyo]

There's a reset you need to do on the brake lining message to get it to go away after it's come up. I don't recall it exactly as I've not done it yet. But it has to do with turning the ignition on to position 1 or 2 (don't remember which) and leaving it there for a minute or so. Then I think you turn the ignition off and it shouldn't come on again.

I had it in position one for quite a while, as I was listening to music while doing an oil change. I'll try position 2 and see what happens.

edit: tried position 2 for 30 seconds, a minute, 2 minutes - brake linings error stays prominently displayed :(

[Tiger]

Use a new wire and just stick it in where sensor would plug in... Do it on both of them, if the light is still on. Then I'd suspect somehow the mechanic damaged it doing the rear wheel bearing... my suspect would be the right rear.

If you got a multimeter, you should be able to measure DC voltage at each plug.

[repenttokyo]

OK - I went out with my multimeter and the wires I am using to short the connection both have voltage, front and rear. I still cannot get the message to go away, no mater how long I leave the key in position ii - 30 seconds, 60 seconds, 2 minutes :(

[whiskychaser]

OK - I went out with my multimeter and the wires I am using to short the connection both have voltage, front and rear. I still cannot get the message to go away, no mater how long I leave the key in position ii - 30 seconds, 60 seconds, 2 minutes :(
I'm guessing you are touching one probe to ground and the other to one of the bare wires you cut and it shows 12V? What do you get if you switch to ohms range and connect to the return wire? If you compare front and back, I would expect on one you will get a reading (on the good connection) and zero on the duff one.

[repenttokyo]

I'm guessing you are touching one probe to ground and the other to one of the bare wires you cut and it shows 12V? What do you get if you switch to ohms range and connect to the return wire? If you compare front and back, I would expect on one you will get a reading (on the good connection) and zero on the duff one.

actually, i had taken the two bare wires, and connected each to one end of my voltmeter just to see if there was current going across. it wasn't anything near 12 volts, but current was there. is this the wrong way to go about it?

[whiskychaser]

actually, i had taken the two bare wires, and connected each to one end of my voltmeter just to see if there was current going across. it wasn't anything near 12 volts, but current was there. is this the wrong way to go about it?
Its not wrong if you got the same voltage on both front and back. I'd want to compare what the supply voltage is (at front and back) with the black lead of the DMM on ground. If the voltage is the same, you know the path out to the sensors is ok. The 'return' (voltage) is going to be monitored so I would not expect this line to go straight to ground. And I would expect there to be the same resistance on both the return wires.

[repenttokyo]

Its not wrong if you got the same voltage on both front and back. I'd want to compare what the supply voltage is (at front and back) with the black lead of the DMM on ground. If the voltage is the same, you know the path out to the sensors is ok. The 'return' (voltage) is going to be monitored so I would not expect this line to go straight to ground. And I would expect there to be the same resistance on both the return wires.

It was different front and rear. Not a huge difference, but noticeable.

Does the presence of voltage indicate that there is NO break anywhere else in the wiring harness?

How can I have voltage at the wires, yet still see the message once they have been jumped?

[whiskychaser]

It was different front and rear. Not a huge difference, but noticeable.

Does the presence of voltage indicate that there is NO break anywhere else in the wiring harness?

How can I have voltage at the wires, yet still see the message once they have been jumped?

The presence of voltage shows you have a +supply. But the way you have your meter connected, it would also show a voltage if one of the returns were shorted to ground somewhere. The circuit that monitors it wouldnt see a return voltage so would throw up the message. Thats why I would be checking the voltages across the meter to ground and then the resistance of the return circuits to spot any differences. Clear as mud??;)

[tim eh?]

I think you should expect something like 5 volts, that's what most sensors run on.


There's a reset you need to do on the brake lining message to get it to go away after it's come up.

If this is true, then the wires must always be jumped. Each time you test it you are probably interrupting the circuit at least once, so you are storing a new code.

To avoid interrupting the circuit you should install your jumper first and test for voltage at the plug to a ground somewhere else on the car.

[repenttokyo]

The presence of voltage shows you have a +supply. But the way you have your meter connected, it would also show a voltage if one of the returns were shorted to ground somewhere. The circuit that monitors it wouldnt see a return voltage so would throw up the message. Thats why I would be checking the voltages across the meter to ground and then the resistance of the return circuits to spot any differences. Clear as mud??;)

yes,that makes total sense. What kind of a resistance should I be seeing to indicate a good circuit?

[whiskychaser]

yes,that makes total sense. What kind of a resistance should I be seeing to indicate a good circuit?
I cant be precise without taking mine apart and even that may not be accurate enough for yours: I've seen specs on tranny speed sensors that were 300 ohms out but when you compared two in reality they were only a couple of ohms apart and worked fine. So the main thing is that the two circuits show very similar resistances.
Incidentally, I have replaced front and rear wear sensors twice, had a break in the front wiring loom and never had to use any reset procedure apart from turning the ignition off and then on again:)

[Ross]

Those "sensors" are nothing more than a piece of wire that will be worn through as the pads approach the end, opening a circuit, tripping the warning light.
Connecting the wires together completes the circuit and will turn out the light.
I've done it a zillion times, it never fails. I even keep a few of the old sensor wires pre- shorted in my tool box.

[repenttokyo]

Those "sensors" are nothing more than a piece of wire that will be worn through as the pads approach the end, opening a circuit, tripping the warning light.
Connecting the wires together completes the circuit and will turn out the light.
I've done it a zillion times, it never fails. I even keep a few of the old sensor wires pre- shorted in my tool box.

hi ross - i know - which is why this is so frustrating. it's just not working for me, which indicates a break in the circuit somewhere.

[Ross]

hi ross - i know - which is why this is so frustrating. it's just not working for me, which indicates a break in the circuit somewhere.

Okay, on the back of the cluster jump pins 10(yel/blu) & 25(yel/brn) on the X16 connector. If that doesn't turn off the warning your cluster is $#$##
Have you checked both sensors? they are wired in series you know.

[repenttokyo]

Okay, on the back of the cluster jump pins 10(yel/blu) & 25(yel/brn) on the X16 connector. If that doesn't turn off the warning your cluster is $#$##

i'm leaning more towards a problem in the wiring harness itself near the right rear wheel - going to experiment with that before I pull the cluster. unfortunately, I am heading off for a 4 day roadtrip tonight, so I will just have to deal with the brake linings message until I get back :(