e39 auto gearbox problem

Hi - I have a 1999 523i with the auto gearbox (5 speed tiptronic).
Just recently it does not like changing up when under harder acceleration. It will operate fine if just tootling around but as soon
as I up the pace it accelerates to the redline but refuses to change up. I can still change up using the tiptronic mode.
The auto change in sports mode is equally troublesome.
The car has done 102,000 miles with the usual full service. No warning lights have ever come on - it was suggested that it could be related to the ABS sensor!!
HELP PLEASE
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rex_uk wrote:

The ABS sensors are the wheel speed sensors and are often used in more than one system, i.e. not always just for the ABS. As for this particular gearbox fault I have no idea other than maybe get the fault codes read.
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The ABS sensor would only give road speed? I'd say it uses engine revs to determine the maximum.
--
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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Had the same problem with my autobox in a 525TDS. It was an ABS sensor that caused the poblem. Seems that there are 5 in the car, one on each wheel and one on the driveaxle coming out of the gearbox to the dif. If that one reads wrong info it chanches th behavour of the gearbox. Cost me 150? to exchange at the BMW Dealer.
Erik
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Erik - did it show up on diagnostics & fault codes?
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No, but the mechanic had seen the problem befor.
Erik
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