U0100

[Barry]

08 keep getting this code. Checked grounds ?
help!!!
runs but rough and slow.

[avguy]

That's a nasty code which can be a RPITA to diagnose. You might start by checking CAN wiring continuity, before hanging on any computer modules.

[06T200]

Definitely check all grounds, and connector 101 (C101) under the coolant tank. Usually a break in the CAN harness or dirty connector. C101 is the weak link. Search for u0100 I have posted my nightmare from years ago.