Something very strange started happening with my 1999 E39 BMW 528IT:
- Occasionally the speedometer stops working (showing a speed of 0
mph), and of course this also messes up the MPG and MPH averages in the
- When that happens, the automatic transmission also goes into FailSafe
mode (gear light goes on the cluster). With the car in "D", the
automatic transmission appears to be stuck into high gear, and is no
longer shifting up or down, making starts from a full stop very
sluggish. However I can still shift into 1st, 2nd or 3rd gear manually
if I want to, so I am guessing that the transmission is working fine,
and that the instrument cluster problems may have something to do with
- The ASC and ABS lights are also on a lot (almost all the time),
although this could be caused by something else (or not...).
I took my car to the nearest BMW dealership, and they say that they
can't read the fault codes (diagnostic equipment cannot establish
connection with computer), so they are at a loss to tell me what is
wrong with my car...
Would it be possible for a faulty instrument cluster to cause such
I don't think the transmission is bad, as I can shift manually - I
suspect that this might an electrical problem of some sort, but without
diagnostic codes, it's hard to tell what to replace before finding the
root cause to the problem...
You only mentioned that the speedo stops working. This can be caused by the
Speed sensor in the differential. (Its in the diff in my car, a '94 3
Series, it could also be located on the output of the transmission.) This
can cause the car to go into Limp Mode because the car needs speed
information as part of what it uses to decide what to do next.
I don't think the trans is faulty either, I think it's responding to the
lack of needed information.
I'll bet a tank of gas that the ABS controller has failed.
Each wheel speed sensor feeds a different speed dependant function - one of
the wheels provides input for the speedo/odo, another for the cruise
control, another provides inputs for the trans program, etc.
Guess where they all come together - the ABS controller. Its a very, very
common fault with the early (1999) Bosch controllers in 5 series cars, there
have been updates that make the replacements much more reliable.
If your BMWshop didn't know that, or couldn't diagnose it, run, don't walk,
away from them, and never let the charlatans try to con you out of another
Controller is about $625 or so from an dealer like Crevier BMW, takes about
5 min to change with the proper torx bit, and will then need an hour at the
( No, not the idiots you went to) dealer or shop with a GT-1 or MODIC tool
to code the controller to your car.
Thanks all for these very insightful suggestions.
I decided to go ahead and have my Bosh ABS module rebuilt by Auto &
Truck Electronics of West Palm Beach, FL
(http://www.autoecu.com/Products/default.asp - module remains the same
- no need to reprogram VIN - repairs come with a 5-year warranty).
I've been driving my 528IT with my rebuilt ABS module for a week now,
and the automatic transmission and speedometer appear to be working
normally again, and the engine and transmission failsafe lights have
gone off. So this appears to confirm that the transmission itself was
not the problem, which is quite a relief.
However, for some obscure reason, the ABS and ASC lights are still
constantly on, even though that the automatic transmission is
functioning normally again. Could this maybe be caused by a faulty
sensor? Or another control module? I remember that these lights
started coming on intermittently about a year ago, long before the
transmission started going into limp mode (which might indicate a
Unfortunately the BMW diagnostic equipment is still unable to connect
to the onboard computer and read any of the fault codes. Would anyone
have other suggestions in regards to those ABS and ASC lights? Is
there any way to reset them (other than going to BMW, who can't do
anything about it)?
Dave Plowman (News) wrote:
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.