P1116 turmoil and a loose wire

Hello all,

I've got a 2009 prius with 225k in Oregon. I've got a persistent p1116 that will not go away. Heres the background on it. Last year I got the red triangle of death while driving and in limp mode I took it to the closest mechanic(which ended up being a big mistake). My memory is foggy but I recall it throwing P1121 and P1116 at that time. The mechanic said he owned a gen 2 and was sure it was the ECU. I was very dubious but I'm not a mechanic and he said he was sure. Quoted about $2000. I asked if he could go used and they did order and install a used one. Got it back, it threw the same codes on the way home. Took it back. He said it was the heater control valve, and replaced it. The p1121 cleared after that. But p1116 came up with sloshing noises being heard under the hood. I told them I thought air was in there and they tried THREE different times to clear it and the slosh finally went away. But p1116 came back soon after. They had my car on and off for 2 weeks and I had enough of them so I just started driving it. That was about 10,000 miles ago and other than than the CE light the car has driven great, no issues. Now its time for smog and its an automatic fail due to the CE. I took it to a new mechanic and he is saying its your inverter pump(very expensive). Before I throw another 1-2k dollars at this old girl, can I get some advice? *I'm guessing this is not related but I just found this loose wire with a... ring terminal that originates under the air filter housing. Any clue what it is? THANK YOU all!