BMW Repair: BMW 540i auto transmission, bmw 540i, diagnostic report

Question
The automatic transmission of my 1997 540i suddenly failed and went into "fail-safe" mode that allowed me to drive the car back home at 5 MPH. It still drives fine in reverse. Any clue what might be the problem?  

Answer
Ghulam, Make sure battery voltage is correct with the car running 13-14.5 Volts with the alternator running. The Trans control module is the most sensative to under voltage. Secondly you need to obtain a diagnostic report of the fault memories to see what faults are stored.
-Evan