The "check brake lining" and "brakes" lights on my 2002 530I recently came on and I replaced all the brake pads and sensors myself due to having some knowledge of doing that. I thought that would make the lights go away but they are still there. Is there something that needs to be reset?If so, how do I go about resetting it?
Also, the "check brake lights" light came on. I replaced the lights and checked the fuses and it is still on. The lights seem to be working fine. What could be the cause. Maybe water got in?
Switch on the ignition without starting the engine and wait until the light goes out. Assuming the wear sensors are in good condition and properly plugged in.
On my E39 it's always the centre light that goes and I forget to check it. ;-)
Thanks Dave!! Good stuff. Switched on car and so said so done - Brake warning lights went off.
When you say the center light, is the same as the 'Rear lamp/side marker lamps'? (that's what it's called in the diagram in the manual). All the other lamps are working fine except for the middle ones on each side. It doesn't easy to change either because it's not one of those quick release bulbs that's easy to manouever. It looks like it'll need some tools. Please advise. Thanks again!!!
I am having similar issues with my E39 (1999 528i)... I had the dealer check lots of stuff, for the "Check Brake Lining" error, they wanted $470 to do rear brake rotors, pads, sensor - I installed the rear parts myself and reset the error. It stayed off for about 20 minutes then came back on while I was bedding the brakepads. Assuming my front brakes are good (and all the new parts I bought for the rear are good), what else could be causing it? I did put new rotors, pads, and a new sensor on - everything went very smooth. Anyone have any ideas why the error came back?
Can anyone explain how the wear sensors work? I looked at them and don't see how or what they actually measure!
I also had the "Check Rear Lights"... the dealer said they put new bulbs in (no charge), but the error came back 2 days later. One of the tail lights was appeared intermittent even though the bulb looked good (new). I cleaned/tightened the socket, applied some electrical jelly and still had some issue. I switched the light to the other side to see if the problem followed, but hasn't been a problem since. Weird.
"Dave Plowman (News)" wrote in news: snipped-for-privacy@davenoise.co.uk:
They are basically just a plastic coated wire. When the pad wears thin the plastic part wears through also and the wire makes contact with the disc, creating a ground. The warning circuit then latches on. It has to latch otherwise the light would flicker due to poor contact. The other refinement is the sensor is part of a loop and if that loop is broken in any way - like the sensor connector not making good contact - the warning circuit will also latch on - this is to prevent running without a sensor.
On the E38 there was a problem with the wiring running under the front fender (wing) liner from the brake sensors and other parts.
It might be worth checking by pulling the fender (wing ) plastic liner and inspecting the run of cables - the clips, apparently, rubbed the insulation away in places and in some extreme cases the wires were broken.
Not quite Dave - it appears the circuit is continuous until the wear brakes the circuit and then the warning bells ring. this is to make sure that the warning is still alive when the brakes are released.
On my E36 once this light has been activated you need to reset the computer to switch it off. BMW dealer will charge you mega bucks but try this - Switch ignition on to position 2 (all lights on) and leave the drivers door open for three minutes. I didn't believe it at first but that's what you pay all that money out for at a main agent.
On my E39 you simply leave the ignition on 'till it goes out - no need to have the door open. It will go out without doing this eventually - it adds up the time the ignition is on without starting the engine.
That's what I thought it might be - b4 I pulled the liner off, I checked both sensors again - both were intact, the front one was completely caked (almost to the rotor) with brake dust. I cleaned it off and cleaned the sensor with brake cleaner. The rear sensor and pads were brand new, but the pads appeared to have a paint coating where the sensor clips, I used I screwdriver to scrape the paint away since the sensor had copper connectors where it clipped (like it needed a good conductor to clip on).
Either way, I reset the code (again) and it hasn't come back on yet (only need a 50 mins of driving, but much longer than b4).
If it comes back on, the fender liner is coming off - thanks for the advice!
Mike
"Dave Plowman (News)" wrote in news: snipped-for-privacy@davenoise.co.uk:
Hmm, could be, but mine were not damaged in any way but the light was on... I clean a bunch of brake dust off and reclipped it all and the error seems to be gone (so far).
Could the sensor be magnetic, when it gets close enough to the pad it opens? Thought about being inductive, but dont think that would work with solid rotors (would prob need calibration too).
I like to know how stuff works (makes it easier to troubleshoot too).
Thanks for the explanation though.
Mike
"Dave Plowman (News)" wrote in news: snipped-for-privacy@davenoise.co.uk:
Kind of thought the copper/brass was more of just a springclip like function since it didnt really seem to contact anything else on the sensor.
Since my light was coming on (its off for now) and the plastic had not even come close to getting eaten up by the rotor, maybe I have bad wire or some other problem (like mentioned in this thread).
By the way, my car (E39) only has 2 sensors, driverside (US) front and passenger side rear!
Mike
snipped-for-privacy@nowhere.com wrote in news: snipped-for-privacy@4ax.com:
Now you mention it I had a similar problem with an old Rover 827 I had and I found out the previous owner had cut the sensor wires either by accident or on purpose when doing some suspension work. I simply made good the damage and bought a new sensor - All was Ok after that and REMEMBER - BMW owned Rover at the time and the later models and the 75 were developed by BMW.
Put a couple hundered miles going to a football game today - American football ;-) and still no light, I think the thorough cleaning of the front sensor did the trick. I think I can get another 5 -10k miles on those rotors/pads/sensor. The back probably had 2 or 3k miles left, but I just did what the dealership recommended. Either way, I am happy with the outcome, thanks for all the tips/advice.
I used Brembo rotors, and thoughts on those (actually got them on Ebay pretty inexpensively).
snipped-for-privacy@nowhere.com wrote in news: snipped-for-privacy@4ax.com:
No. Don't make it more complicated than it is. It is a wire loop. If continuity is broken by wear against the rotor or by a bad connection in the circuit, you'll get a warning lamp. Been that way since the early '80s.
The sensor looks much the same as a fuse, the fusable link is placed across a plastic block. As the brakes wear down, the link makes contact with the rotor and wears through. I believe the contact will set off the warning light, but am not positive. The link breaks (wears through) and this keeps the warning light on, even though service has been completed.
In order to get the warning light to go off, the sensor must be replaced. On my E36, the warning went off by itself after the sesnor was replaced.
IIRC, it doesn't have to wear through - just make contact with the disc. That's why it's plastic coated. But once it has made contact the warning latches on. The loop is part of a security circuit to prevent it not being replaced or plugged in properly.
On my E39 it depends on the length of time the ignition is on without the engine running. And adds these periods up. So will take usually a few days to go out if you don't re-set it by simply leaving the ignition on for a couple of minutes.
I believe you are right on that one Dave. There only needs to be contact. Sufficient contact to break it does not take long though.
"Couple" of minutes is accurate. I STARTED the car and the light did not go out. I messed around with something, switched the ignition to on again, but not start, and went to the bathroom. When I got back, the warning was cleared.
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