I have a 2007.5 6.7L Cummins was driving, the engine stalled, and the truck ran fine.

Red flashes on the dash and check engine light with no DTC with Harbor Freight scanner.

The crankshaft position sensor was damaged, so I replaced it.

Batteries are two years old at 12.68 volts, and the scanner says ECM sees 12.4 volts.

Key to start, nothing happens.

Plugged in Smarty Jr, which has been on truck for 10 years, gets communication errors 121, 122, and 116.

Smarty expert thinks the ECM is bad.

I am trying to figure out how to confirm whether ECM needs repair or replacement.

I don’t want to lose tune if possible. Can anyone on this site give advice?