A couple months ago I took the car (2000 528i) for inspection to a local,
non-BMW shop. It passed and I picked up the car at the end of the day. As
soon as I started it the BRAKE/ABS light on the dash came on. It comes on
and goes off. It's very intermittant.
I called the shop the next morning asking if they accidentally might have
disconnected something by mistake, but as you can guess they completely
washed their hands of any wrongdoing.'
Well the light continues to come on and off, and it's mostly on, and I
believe the ABS does not function.
You are describing the symptoms of a bad wheel speed sensor.
I doubt that the service activity and the sensor problem are related. Having
said that, there is a way that the ABS valve body can generate an error that
will turn the light on. If this is the problem, the light will come on after
the car is started, but before you begnin moving, or it might come on after
using the brakes. The Speed Sensor related failure will come on for no
apparent reason as you are driving down the road. The Speed Sensor error
will clear itself when the car is shut off and restarted, but my
recollection is that the valve body error will set and remain -- I'm a bit
fuzzy on that detail though.
You are correct, the ABS system is not functioning when the light is ON. If
the light is not on, the ABS should function normally.
Speed sensors on my E36 run to about $100 each. It is expensive to buy
enough to do the car when only one of them is needed.
I'm a wee bit confused though, I described two conditions. Which do you
On my first E36, I could not correct the malfunction by cleaning them.
I don't know the incidence of failure vs. getting dirty. I'd always try
cleaning the metal dust off of them, and cleaning the connectors first, but
my limited experience is that if there is an error, it takes replacment to
The diagnostic port will tell you what the problem really is.
My 99' 528i is having intermittemnt issues with the ABS. The ABS light
is on contiuously, I replaced the wheel sensors in the rear, about 80
bucks apiece.... no biggy. I have reset the comp a few times during
maintenance, however the light stays on solid. The speedo jumps from
zero to normal speeds every once in a while, (I could drive for a few
hundred miles then the speedo works again), and of course the light is
on always. It's a stupid design to incorporate speedo mileage
indicator ABS system having multiple things into what could be a very
pricing perportioning value.
I have contacted a few wrecking yards, one needs to be aware of the
correct serial number sequence I think they mentioned "001" as the key
indicator when purchasing the correct replacement. I think they
mentioned 99' and 00' used the same block and sending device. Then
they changed it again in 01' going forward.
I heard they're rebuild units for a few hundred bucks, but that could
be a hit and miss issue. The wrecking yards charge 450 bucks for the
unit and you can get a shop to swap it out and bleed the system and
resync it for around 100 addition dollars.
What a pain in the ass for a known auto maker such as BMW to design
and continue to support this type of lousey system. ABS or not it is
BTW -- new uninstalled part BMW is asking around 1500.00....
Sorry for the rant..... just had to make point
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