My 450J won't move now, and it won't rev up beyond idle. The dash screen should show 1.6 for the speed, and it just shows a dash (- -) now. Seems like it's not getting any signal. Every now and then it will rev up randomly, and only let me move it forward and to the left, then randomly stop and rev down. I pulled the cover off the TCU (behind the seat on the left) and found that it was dirty and mice had been in there. There's buttons and a readout to view codes, I'm not even able to view codes because it appears to have a bad connection. The Status light flashes on and off, and/or is very weak. I plan on cleaning up the ground and everything else I can, but I'm looking for any other ideas on fixes. The TCU is $5,100 through Deere, so obviously I would try quite a bit before I did that. Thanks.
Mice like to nibble on wires. Check the wiring harness at the TCU.
Also check wire harnesses at the throttle control and the transmission control. Mice like to hang out there too .