Tmcc wont reverse

The last two times I had that issue, it was the opto-coupler on the DCDR board.  It could also be the R2LC, as there are two pins that send the forward and reverse PWM signals to the DCDR for motion control.  Naturally, it could also be the connections between them.

Try reseating all the boards and connectors first, and inspect the wiring harness between the TMCC motherboard and the DCDR motor driver module.

What model?  AC or DC motors?  Sometimes it can be connections on the motors if AC.  Otherwise what John has said.  G

The VCO circuit ramps up diesel sounds.  You may want to try swapping a DCDR in from a like engine if you have one.  G

Will the engine run in reverse in conventional mode.

Bill