BMW Repair: BMW 330 SMG problem, bmw 330 coupe, electro hydraulics

Question
Hi,

I have a BMW 330 Coupe 2002 with 5-gear SMG transmission. The transmission has a problem: the car doesn't move but always acts like in neutral gear. If I press the accelerator hard to get a lot of RPMs, then the car starts crawling. All gears shift normally, they just don't work. Sometimes, very rarely, the car works normally for a short period!

Clutch, SMG control box and (apparently faulty) transmission speed sensor have been replaced, but nothing has changed. It now starts to feel like a problem with the electro-hydraulics outside the transmission itself.. But nobody has any real idea what the faulty part could be, not even BMW service. There are no fault codes available.

Answer
Teemu, I would look at the Slave cylinder with integrated clutch position sensor (PLCD). Does the system have pressure to the slave cylinder? Make sure the hood switches are good or the car will never go into gear. I would replace the SMG relay for good measure and make sure that the 23 01 04 service action was carried out correctly. Does the vehicle go through the test plans for teaching in the next clutch normally? It sounds like the problem is with the clutch engagement. I see if you can get another car on the diagnosis machine and see which values are out of spec. Z4 with SMG is the same system.
-Evan