TMCC engine only runs in coventional mode

Make sure the antenna is connected.  With the shell off, connect a chunk of wire to the antenna connection and see if that helps.  Also try reprogramming it.

Thanks for the quick reply. I tried the wire to the antenna connection, and it still just comes on in conventional mode. How do I reprogram it in conventional?

Here is the procedure to reprogram and reset TMCC functions.  It should work as long as the antenna is connected and the TMCC radio board is ok.  

Bob

Thanks for the info. I'll look it over. Right now it won't come up in command mode at all.

Try to re-seat the connection between the tender and engine. Also, check all connections to the boards in both the engine and tender.

With the cab off the tender and engine. Check continuity on the wired tether.

As you inferred,  can't reset if it does not come up in command mode, regardless if it is in program mode.

If it really can't see the TMCC signal, I'd suspect the LCRU has a problem.  You can get a replacement or upgrade to the ERR AC Commander.

Hard hard is the AC Commander to install? That sounds like something I might have to check into...........

@Barry Franklin posted:

Hard hard is the AC Commander to install? That sounds like something I might have to check into...........

It's not that difficult for a simple install.

I'd check to make sure the PROG/RUN switch is good before ordering a replacement board.  With the switch in one position, there should be continuity (close to zero Ohms resistance on a multi-meter) between the two switch terminals with wires attached.  In the other position, there should be infinite resistance between those same two terminals.