E34 Trans Program

[DrewDepo]

My 1993 525i throws itself into limp mode after driving for about 15 minutes, it seems to get stuck in 3rd gear, the D and E lights on the dash disappear when this happens. If I follow the code it gives me it tells me that the alternator needs to be replaced. I tested the alternator and its fine, it's putting out the right voltage and it's still charging the battery just fine, any ideas?

[shogun]

The transmission is controlled by the driver through two switches - "S/E/M" Program Switch and "Shifter Selector" Switch. Both switches are subject to wear and may be desired to be reconditioned thereby avoiding expenses. Here I show how to take them apart for examination and reconditioning...the code plate element provides 7 tracks that are responsible for translation of code to transmission electronics and the speedometer. The wiper provides a bridge for current to traverse from top track to others depending on position of the shifter, so that the code can be established.
http://twrite.org/shogunnew/otherMod...nsmission.html

what is the alternator voltage?? A too low voltage can also cause limp mode.

[whiskychaser]

Do you have the 'Trans Program' warning in the cluster too? What is the fault code? Is it in the transmission control module and is it currently present?

[DrewDepo]

Thanks, I'll check the switch this weekend and hopefully that fixes the problem.