Trans. failsafe [Archive] - Bimmerfest - BMW Forums

: Trans. failsafe

04-24-2005, 03:24 PM
The other day my wife was driving the 98 540 and after parking for a few minutes pulling out of the parking lot the check engine soon light, car became sluggish and trans. failsafe indication on the display.

I checked it out tonight and after checking battery set parking brake and started car, fault is still there and in failsafe mode (4th gear). No warning, gridning sounds or anything. Another thing I noticed was with the transmission indicator, even though the tranny was in park, the N (neutral) light was illuminated, and when I choose R or another gear, they are all dimmed.

Any ideas, do I need a new tranny? I have searched message boards and there is not much on this.

undefinedIdeas would be appreciated.

04-24-2005, 09:47 PM
Are you also getting other weird unrelated electrical things going wrong (radio, airbag etc)? Believe it or not, a faulty ignition switch can cause all these things.

04-25-2005, 09:37 AM
No other anomolies, just the transmission gear indicator and the messages I identified in the original post. I spoke with BMW service tech this monring and he said might be the neutral safety switch? How bad is that to replace?

05-06-2005, 09:24 AM
Turned out to be the MAP sensor (coolant temperature attached to the thermostat) Don't really understand the conection but that fixed it.