E39 Cluster, Speedometer and Failsafe mode Transmission problems

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
on-board computer. - 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 this. - 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 problems?
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...
Thanks,
JP Abello
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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.

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It's gone into 'limp home' mode.

Quite likely - IIRC, the speedo speed transmitter is also involved in this.

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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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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 dime.
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.

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You can get service exchange units for less than half that - but not from BMW. I believe they're advertised on ebay in the US.
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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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 different problem).
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)?
Thanks,
JP Abello
Dave Plowman (News) wrote:

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