I have a 2004 E46 Convertible 30K miles. Worked great up until about two months ago when my SMG started to go wacky.

Will be driving and then Transmission light comes on, followed soon afterwards by the car going into Neutral. Sometimes have to play with it and it will go back into gear, others it just goes back into gear on its own while I am coasting.

Brought to the dealer 1st time, they found nothing wrong. Two days later, same problem. Brought in again and was told it was a faulty hose (they thought it was the accumulator, found leaky hose behind accumulator). Happened again last week - brought it in and they replaced the accumulator, bled the system, etc.

Picked it up today. Drove it approx 60 miles and lo and behold - it starts again!

Any ideas - I am at a loss here!

seems like the pump itself might be going bad. if your still under warranty, keep taking it back

Probably smg pump,

My car started doing this at 14K, I took it to the dealer 5 times for the same problem (over a year+). At the end it is hopefully fixed after changing pump, accumulator, and relay.
See my SMG thread here:

http://www.m3forum.net/m3forum/showthread.php?t=172265

Good Luck!!!

I have a 2004 E46 Convertible 30K miles. Worked great up until about two months ago when my SMG started to go wacky.

Will be driving and then Transmission light comes on, followed soon afterwards by the car going into Neutral. Sometimes have to play with it and it will go back into gear, others it just goes back into gear on its own while I am coasting.

Brought to the dealer 1st time, they found nothing wrong. Two days later, same problem. Brought in again and was told it was a faulty hose (they thought it was the accumulator, found leaky hose behind accumulator). Happened again last week - brought it in and they replaced the accumulator, bled the system, etc.

Picked it up today. Drove it approx 60 miles and lo and behold - it starts again!

Any ideas - I am at a loss here!

I would recommend pounding on the service department door to get it fixed right so you dont that this problem any more. I have an '04 vert with SMG and have never had this issue. The gear light came on once while driving but nothing happened and shortly after turned off.

Check the hood sensor and the door sensor, it happened to me a week after I got my M3, SMG kept going back to neutral, problem was fixed after replacing the hood sensor

what is the hood sensor? is it easy to replace?

that gear light has come on for me about 3 or 4 times now in the year i've had the car. cause of warranty i'd bring it to the dealership. each time, they would keep my car for a bit to look into it, make some minor fix, and then the gear light would show up again within a week or two. never actually saw any odd shifting behavior as a result of it though

smg pump.. get it checked