BMW 740il 1999 Erratic Computer

1999 BMW 740
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BMW2DAY
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Alarm LED displayed Trans Prob-Failsafe after 30 minutes after driving approx 30 minutes (speeds 35 to 80 mph). Also begin displaying (intermittently) warning lights for brake (lining), ABS, DSC, and check engine. Finally, I noticed that the speedometer and tach were not working at various intervals. Sometimes the a/c compressor would shut down.

I then made an appointment with a reputable BMW independent mechanic who decided that the transmission must be faulty. Then I took the car to his recommended transmission shop, Aamco. Aamco tested the car and determined that the transmission was ok. They even observed the car returned to normal during a portion of their road testing.

On their recommendation, I had the car towed to the dealer. The dealer had the car over the weekend but was only able to get to it by the following Tuesday. Now, three days after the dealer was able to start his investigation, no one has any answers to the problem.

What do you suggest?

Make BMW
Model 740il
Year 1999
Mileage 95K
Engine Size V8 4.4l 282hp
Apr 25, 2007 at 11:35 PM
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2CARPRO JACK
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Just had one similar to that and the ignition switch took care of the problem. It was throwing trans codes, brake light warnings, just about everything, but at erratic times. If i remember correctly it was a 2000 740i
Apr 26, 2007 at 8:16 AM
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BMW2DAY
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Problem turned out to be a faulty DSC controller. Repair cost $1700. Dealer first noticed the relay associated with the controller was bad. He then replaced the relay and it immediately failed. When he replaced both the DSC module and relay, everything worked. Repair was expensive, but the dealer spent approx one week total in the troubleshooting. Besides the high repair bill, my disappointment is in BMW for not providing more diagnostic backup for a problem that should have been more obvious.
May 6, 2007 at 11:53 PM
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MERLIN2021
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The ultimate driving machine?
May 7, 2007 at 5:04 PM