Desbord lights didn't come on and the car can't start. My battery is new

Dtc P0335 and p0340 faults

It happened that a storm came and i am currently out of the country, and the vehicle was half body flooded, i replace the ecu and the immobilizer module. And the car starts after a few weeks the car instantly shut down and wont start. And i observe when i turned on the key from lock position to acc it has no power, and when i position the blade key on the on position the dashboard indicator illuminates but the check engine light doesnt and it only appear when some of the dash light goes off same goes with the alternator indicator, i observed also that there is no PRND indicator on the dashboard. When i inserted the obd scan tool it says ECM/PCM EV error. And cant communicate with the ECU
What could be the possible issue of this problem?

Car was running while I disconnected 1st ignition lead then as it began to stall I reconnected the lead and the engine cut out and would not start again. I replaced the leads and spark plugs but still no spark from the distributor.