ECM not detected

Hello and thanks for reading, I have a 2001 3.4 with 164K miles automatic 4-door Prerunner. First time posting, I did search around in here but see nothing similar to my problem. I'm hoping someone can help me out. A few days ago I went to start it and it turned over a few times then click, click, click. After inspecting the battery I discovered some corrosion on the terminals, after cleaning them up it cranked over but ran ruff and white-blueish smoke with a heavy gas smell coming from the exhaust, almost as if the injectors are running wide open. I tried to read any codes but the ECM is not detected, I borrowed another scanner and same results. It will run but is extremely ruff. The truck had been driven a few days before with zero issues. All other electronics seem to be in working order. I've pulled the computer and everything looks good inside it, I have also ordered a replacement from a salvage yard, with the same part number. My concern is what caused it and what can I do to prevent this from happening again. I've ohmed out the grounds and given the harness a good look over for any critters or abrasions but all looks well. We live in the East TN area, any help or suggestions would be appreciated.

 

Usually leaking windshield, if it hasn’t been fixed it will happen again.

 

Thanks, Bishop84, the windshield was actually replaced a year ago. We did have some pretty bad storms the night before. Are you thinking the computer got wet, everything was dry inside the truck.

 

Dirt or corrosion can also cause a failure to connect !

in fact it happens to me quite often when helping other people out.

A little cleaning fixes the issue.

 

Usually when you plug a scanner into the OBDII connector an LED lights up on the device somewhere to verify there is power to the connector. On the OBDII under dash connector check pin 16 for battery power and pin 4 for ground.

https://www.researchgate.net/figure/ELM327-OBD-II-connector-and-pinout_fig4_300350886

In addition, the PCM needs to have a minimum of 9.6 volts for it to power up.