Failed ECU any help appreciated
 

Posting this here as Ash8's part thread is not seeing any help.

I'm in the unfortunate position of having to replace my ECU. Dealer if having problem finding a used one. I have an ECU Number N3H6 18 881M, I found the first replacement with this exact number (shipped out of California, I'm in Canada) failed on a final stage of the swap with a communication error. Not sure it it was a bad ECU or an incompatibility with a California units. Looking for another replacement but cant find another of that complete number. Here's the question will any ECU with the same initial 9 numbers work? I can find J,K, and L's just not another M. Does the last letter represent the Flash level ship or is each letter increment hardware change? Dealer also indicated N3Z2-18881L and N3ZD-18881B should work but they have not been able to find one of these either (they are unsure about the last digit question). Same problem 9 digits but not the final letter

Appreciate any incite.

One update: today the dealer supplied ECU (same part number as the original) same problem. Fails to communicate at the last stage.

I had issues when I reprogrammed a used one with the WDS not keeping a good connection on the OBD port

Check the pins on the connector

The connection was verified by the dealer using the WDS and the original ECU , communication... checked out OK.

The Issue requiring the swap is an immobilizer activation at low temperatures that was tracked back to the ECU, I could be remedied the problem by applying localized heat to the ECU? Not a very practical solution for a daily driver in winter.