Just been reading some of your R34 Tiptronic threads...
I've had problems with my R34 box for nearly 2 years now, initially showing as Line Pressure Solenoid on diagnostics, and causing very harsh gearchanges. The car has done around 100,000km with the last 40,000 being with me, so pretty harsh!!
I put in new solenoids myself. No benefit.
I swapped engine ECU's. No benefit.
I replaced the gearbox ECU. No benefit.
I put in a replacement gearbox myself. No benefit.
I did electrical tests and found throttle position sensor was very slightly dodgy.
Installed new throttle position sensor... and problem CURED!
Installed bigger turbo and re-mapped standard ECU, giving 400hp, but whilst on rolling road it threw
another gearbox problem which eventually was cured by a new ballast resistor (down near battery).
Since putting some miles on it, the gearbox is coping fine (has a larger cooler now) apart from it's 1st to 2nd change which is now way to slow for the increased power (slams into rev limiter)... Recently, these changes can sometimes cause it to default into limp-home mode (which involves an ignition on-off to reset).
So whilst seeking out others peoples ideas on speeding the 1st-2nd change (I'm thinking of putting a switch into the Line Pressure Solenoid wire to give me full pressure changes, unless I can 'teach' it to change quicker???) what i'm trying to say is...
Don't always rely on the diagnostics... I could have saved many hours of changing gearboxes, solenoids etc. by trying the cheaper easier options first!
