A/C issues - intermittent Red Triangle + Radiator icon

My 2009 Prius (337,787 miles) has been having an issue with the red triangle + coolant icon coming on and going off intermittently since 2023. Every time I get it fixed, the issue it comes back within a few days to weeks. I am looking to see if anyone might have some thoughts on what could be causing the issue and maybe a fix.

I no longer have a catalytic converter, so I do get the O2 sensor code periodically and the check engine light comes on and stays until I replace the gas cap.

So far, my poor car has spent 6 months and $4k at the dealer, then quality time in the garage when I had no funds to try again...as the dealer indicated they would need more $$ to continue.

Then I decide to try a local mechanic who has tried his best to fix things - basically rebuilt the whole main engine A/C system as it seems the main A/C system was full of sludge - best guess is the dealer put stop leak or something in it to "fix" the code problem - and I had no air conditioning or heat.

I picked it up and started to drive it home and got lights again. He replaced a couple more parts and basically kept testing it until he didn't get any lights. 3 weeks later I picked it up and brought it home. Took it out for a grocery run and on the return trip home I got the red triangle + coolant icon and no more cold air.

I have had the following done thus far:

At the dealer - over a period of 6 months for codes:

P1150

P1121

P1151

P1116

P0117

Replaced Radiator (16041-21281)

Replaced Condenser (88460-AZ010)

Replaced Radiator temperature switch (8947-47010)

Replaced housing connector (90980-11235)

Repaired terminal (82998-12440)

Replaced Coolant Flow valve Water Valve Assy, Water (16670-21010)

Replaced coolant heat storage tank (16660-21011)


Local mechanic codes and replaced the following -
P1116
P1121
Replaced Air Door actuator

Replaced Heater Core

Replaced Evaporator Core

New Antifreeze/Coolant

Fresh Refrigerant

Replaced Auxiliary Heater tank

Replaced the thermostat and housing (as the housing was in bad shape)

Replaced the coolant temperature sensor

Bled both A/C systems (engine & hybrid) to get all the air bubbles out.

And I now have code P1116 again, and no cold air.

At this point I may have to sell it as it doesn't seem to want to be fixed. Which I really don't want to as this car has been the best car I've had until this point. I bought it new.

Please note - the alarm lights are intermittent, they stay on a bit and then go away. Sometimes they do not come on at all, sometimes they go off and on during a trip, sometimes they actually stay on and I can get a reading of the codes. The codes tend to disappear, and the dealer began to think I was crazy. I bought a Blue Driver scanner so I could run a scan while driving to show the dealer that the codes were occurring...as well as video. I have yet to find any pattern with the alarms...no combination trigger. It's very frustrating.

I am hoping someone else has had a similar issue and actually got it fixed so it worked. Or maybe there's a Toyota mechanic who has a suggestion.