Hi. Every morning when I pull the BMW in reverse, the failsafe message appears. The message warn me that the reverse might not engage and acclerator might be reduced. I switch it off and restart. After a few attempts I can drive it. Since yesterday this issue is appearing again and again but most when the vehicle is cold. Can anybody guide me on the root cause?
Last edited by Jawad Downunder; 03-02-2018 at 05:49 PM. Reason: Missing model no
Are you a DIY'er? The issue could be electrical or mechanical, but IMO since its its intermittent and if it drove normally when working there are strong odds the transmission main assembly is still fine.
If it were me, I'd start by scanning the codes, without that what is wrong is just a guess. often if its an electrical issue the code will directly point to it (like when I had a bad solenoid preventing mine from shifting out of park), or if its one of the seals that goes bad it might show deficient line pressure somewhere. I got a carly OBDII scanner which is pretty basic and limited (but pretty cheap too). Works via wifi with an app that lets your phone scan the car.
If the trans hasn't been serviced in a while I'd also plan on replacing the bridge seal, sleeve seals, mechatronic sleeve. This will necessitate a fluid and pan/filter change as well. And personally I'd rebuild the valvebody while in there, its not difficult just a bit tedious. If you have to replace a solenoid you'd have to pull the VB anyway so you might as well, and if one solenoid is bad I'd just change them all (and I did). VB removal also requires a separator plate (has bonded gasket that seals VB to the trans case).
GL
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