New TMCC locomotive - Lights flashing in cab

#1 that's an earlier Odyssey with the magnet ring. I just went through this on a local repair engine- they crack, they are known to crack, something to keep spare in your parts box for one of these engines. Pretty simple, if the ring cracks, you have no speed feedback- so you get runaway.

#2 I'm not saying you cannot go back to the seller, but it's an older engine. It worked when you got it. It now 30 days later- had a $2 part fail. It's not $2 to install the part, but basically, again, it's NOT expensive and they are known to fail.

Lionel parts

https://www.lionelsupport.com/...-SD40-2-3593-6-18298

The part that likely failed and is your runaway problem

https://www.lionelsupport.com/...FLYWHEEL-MAGNET-RING

Also, if you get the ring, the original flywheel was pressed on but the repair flywheel (to use with a new magnetic encoder ring) uses a setscrew vs pressing on the shaft. https://www.lionelsupport.com/...REW-ODYSSEY-1-FIX-IT

Oh look, the identical engine, and exact same failure- and pictures and details of others making that fix

https://ogrforum.ogaugerr.com/...ey-1-fix-it-flywheel

As for the not responding and programming.

Again, in theory, the lack of the odyssey ring supporting the speed feedback function it might stop. In other words, it runs full speed trying to reach the RPM commanded, however, since the tachometer cannot report that speed, it keeps raising the motor power= runaway, but then also, it should then stop to prevent motor burnout in the case of a locked rotor.

As for the cab lights blinking.- a couple of thoughts

#1 this broken missing magnet ring might be jamming, shaking or moving the cover around the motor that the cab lights might be mounted to. I just had such a failure and it blew out both grain of wheat bulbs when the magnet flying off the flywheel struck the motor cover and shook the bulbs so hard the filaments broke/burned out.

#2 On the engine I was working on, cab lights were directly wired to track power from the front pickup wires- no electronics involved.

#3 If they were off of electronics- on a newer Legacy loco- a failed tachometer or jammed motor might give the warning and blink the cab lights, but on this older Odyssey model- like I said, those lights were not connected to the board in any way.

#4 Alternatively, if you made a mistake during programming, and set the wrong engine type code after setting ID- that could cause problems too (not speed runaway like a failed tach) but lights that blink rather than steady. Again, I would ensure you set the feature code per the reset procedure of the manual https://www.lionelsupport.com/...ents/72-8524-250.pdf

Also, owning TMCC engines- print this off and keep near your layout or handy. TMCC reset instructions

Your Diesel engine is type 8- however always good to reference the manual since it can be a specific code for certain engines.

I had a similar problem and it turned out to be the internal antenna had become disconnected.