If the model doesn't make any strange noises when placed on powered DCC track and no decoder smoke is coming from the model try to see if you can go into DCC program mode and get a response from the decoder. The programmer should give an error it can not talk to the decoder.
If nothing - perhaps still a wiring/connection issue - be sure you have track power and the locomotive is picking up DCC power.
If all that still doesn't could be a toasted decoder, but try testing using a Decoder Test Stand if available.
DC voltmeters doesn't measure DCC power correctly so you need a special device for that - but it you can use it with the locomotive at the workbench to test wire connectivity.
Beware that DCC wiring is not forgiving like DC.
If nothing - perhaps still a wiring/connection issue - be sure you have track power and the locomotive is picking up DCC power.
If all that still doesn't could be a toasted decoder, but try testing using a Decoder Test Stand if available.
DC voltmeters doesn't measure DCC power correctly so you need a special device for that - but it you can use it with the locomotive at the workbench to test wire connectivity.
Beware that DCC wiring is not forgiving like DC.