Code P2185, I turned on the car, it made a weird sound, then overheated and was smoking?

I installed a new radiator, thermostat and hoses in my mom's car. A mechanic wanted $587.00 for the repair. No way Jose, lol. I went to bleed the system of air and as soon as I turned on the car it made a weird sound then overheated and was smoking. All in less than a minute. I plugged my obd2 scanner and got the p2185 code which is the ect 2 sensor by the radiator driver's side. I inspected the connector and saw a lot of coolant in there. I called my mechanic friend and he said to spray brake cleaner. What baffles me is I checked the code said p2185 and then two times after said no codes found and then the p2185 code. The code didn't come on until I did this repair, so the sensor had to have been fine. I know coolant leaked onto it because of the coolant draining but I'd really like to know why it said no codes were found intermittently. Maybe I cleared the connection a bit with the brake cleaner and it came back. Here is a picture of the connector as soon as I disconnected it from the connection piece along with video after I started the car. Is p2185 most commonly associated with that particular sensor and not the thermostat or low coolant? Can it bd just spliced or does it have to be soldered? I have a multimeter. Please tell me how to test, I assume ohms on the male and female connectors?