Patric

My 14 E63S has 14K miles on it and the last few weeks it sometimes does not want to downshift into first when coming to a stop. It will start out in second as a result. It does this perhaps once in every four or five stops so not all the time. I usually run S+ around town but it also is doing it in C and S as well. Other than that the transmission acts normal as it has done since new. The car has a Renntech tune but has had that for almost a year and a half so I doubt that is all of a sudden the problem.

I'll have to have Renntech remove the tune if I have to take it into the dealer. The car has had the 10K service but no updates and was delivered in April of 14.

Anyone else experience this?

Thanks in advance.

2012 CCB E63

C this is normal
S and S+ this is not normal

PeterUbers

I would reset the tcu and re adapt that trans keeping it in s or s+ for 200 miles

Would do this before messing with the tune removal

Patric

So if it's just a matter of in essence erasing the transmission's memory, how do I reset the tcu?

PeterUbers

1. Turn the igniiton key to the "on" position which is just before you crank the engine to start.
2. Press the accelerator to the floor and hold for 5 seconds.
3. Then turn the key to the off position but do not remove the key, then release the accelerator.
4. Wait at least 2 minutes

Patric

That fixed the problem.

Thanks very much.