2000 540 transmission problem when hot

[headhound]

My 540 with 155,000 miles and Steptronic is having a problem when the weather is warm (70+). I will be cruising when the car has been running for a while and the transmission will drop into the failsafe mode. If I keep driving the service engine light will come on. Stopping and restarting the car wil lsometimes reset it but on a warm day that doesn't work.

The PRDL are all lit on the dash display. I had it checked at a good shop where they checked the codes and several solenoids were replaced just before winter. Runs like a champ otherwise.

Anyone have a similar experience and was able to find a solution? Thanks!

[headhound]

Bump!

[sp0rky]

*usually* when the check engine light comes on along with a trans failsafe, the problem is the torque converter. I'd have it checked out by a respectable transmission service shop to know for sure.

[headhound]

I did that. They analyzed the transmission and it is fine. The shop localized the root causesto a communications network error and said to go to a BMW dealership. Delarship said "bad tranny" and never even checked with the shop. Other things have occurred to make me believe the BMW dealership service department is not good on diagnostics. Just replace parts and see what fixes it.