MindBend

My '06 E55 is shifting really hard. It's not related to any particular gear and does it on light-throttle, casual driving just as much as WOT.

Trans adaptations via STAR DAS all are acceptable, but a code of IMPERMISSIBLE TRANSMISSION RATIO was stored. Dealer blames it on TCU.

Fluid level good, fluid is clear and clean.

Any idea where to go with this issue next? Dealer doesn't do trans repairs. Just get reman units!

Lelix

Make sure the TCU is not full of oil. The electrical plug tends to leak and the oil travels up the harness into the TCU. If its dry, I would start with a conductor plate.

Dawson718

What is a conductor plate

MindBend

Just had my TCU upgraded last month and didn't notice anything, but was not specifically looking for it either.
Guess it's time to drop the pan and swap some parts!