ecu problem

My car by accident I wet it with water, didn't dry it yet instead I start driving now my D4 light is not lit plus my car barely move. I had to shift gear to D2 then D3 but it's still slow. I uses the car code reader it gave me a code I look up the code it's my ecu. So how can I reset the computer to where it will operate normal again? Is there a way to manual reset it ? ..or ... .