I bought a 2007 328xi with the 6sp steptronic, (my 4th BMW first xi), and I discovered a strange transmission behavior. (Thanks to the "angels" in the white van who pulled out in front of me so I could discover this.)
If I'm in drive, going fast enough that the car is in 6th gear, and I have to hit the brakes fairly hard,(slow to 10-20mph) then I immediately floor it, The transmission is extremely slow, and it only downshifts one gear at a time.
Before the dealer worked on it I think the NIC was active, because the car seemed to be just coasting as the engine steps up rpm (1000, 1500, more, more, Oh there we go!)
From the time I punch it to the time the car gets into 2nd or 1st and takes off well is 3 seconds or more.
Here's all the stuff I know so far:
I am going to the floor and hitting the kick-down switch
Putting it in DS as I'm braking doesn't help.
Clearing the adaptations in the transmission helps very little.
The dealer talked to BMW, and installed new software in both the DME and the Transmission control unit. It now provides some power as it's downshifting, just not much as it's still in too high a gear.
The only thing that does seem to work is using the time I'm braking to go into manual mode and downshift myself.
I will try with DSC off and DTC on,
then with both off.
I don't want to drive like that every time, but it might help isolate the cause.
Would someone with an 07 or later 328xi Steptronic try this out for me?
Also is there a good OBDII data logger that someone has used that works well.
I'd really like to chart exactly what's going on so I can suggest a fix.
Thanks in advance
