P0A08 and I have to pee! Can I drive at all?

I understand that idling in heat will be hard on a car... this time was not planned, just was mixed up schedules between my son and I meeting to move him out of an apartment and I did some work in the car waiting for him. I'm just curious how the people who camp in their prii handle that? With my 2009, I remember choosing to sleep in my car once vs setting up a tent at 11pm, but it was so hot out (in SD in September it was over 95 degrees) that I ended up rolling up windows and sleeping with A/C on. That would have been 5 hours or so... maybe I just got lucky.

So - sounds like I'm headed to a dealer no matter what. Exactly what I was hoping to avoid. $230+tax just to walk in the door and that amount of money is hard for me... but of course as you point out, better than damaging entire engine. I guess I need to encourage one of my mechanically inclined children to get certified!

I did tell them to move forward replacing the original 9.5-year-old Yuasa 12v battery.

 

I had them proceed - they were kind of astonished, given the car was put into service in late 2016. That needed to be done even if it doesn't solve anything else. Glad you like your new one. Hopefully you don't have reason to reset it often.

 

I have personally never had to add coolant. I only checked the small reservoir for the inverter coolant, but the shop said they checked both and it was fine.

 

Here is the latest word on AC from mechanic:

"I checked both the pressures in the AC system and I believe that the system is overcharged. Therefore, at idle the pressure gets too high and the system shuts down. Cleaning the radiator is recommended, might help, but does not fix the underlying overcharge situation. We can do the cleaning first and see if it gets us close enough or not. And it needs to be done regardless. Other possibilities exist, but all further AC diagnostics require starting with a known properly charged system so it is our first step after the radiator cleaning. Short term, you can leave it, but it is stressing out the compressor."

EDITED TO ADD - I have never charged or recharged the AC, so it has gone 45k miles "as is" from the dealer in January 2025. Problem at idle started this year, whenever Minnesota warmed up.

And on overheat:

"I believe the code and overheating hybrid cooling system is due to a failing water pump. I can't prove that."

Sooooo. New 12v battery is in... *** Do I move on with either evacuate and recharge the AC? or the radiator clean (they say they have adapted a tool to do this well, but still charge a couple hundred $$)? And hope that whole improvement reduces the chances of overheating?

First three codes are P0171 (never saw that before myself - could be gas or O2 sensor maybe?), P0A08, and then B1503 (also I've never been able to read that before).

I like the approach of fixing one thing and then seeing the fallout before moving forward. BUT I'm not sure swapping 12v will be the end of it - what would be the next logical step? Hard to say if I have one problem or two... (or more)

Do I get the car back and drive without AC and see if it ever overheats again? Or fix the AC and then wait and see? I do a LOT of driving on rural highways where I will be pretty good and stranded if it gives out on me. Not sure how long I can last without AC either - I start melting, lol.

 

@rjparker I was typing while you were. I will digest your posts and read the links. Thank you.

 

He was proposing cleaning radiator FINS I think... not necessarily drain and fill... is that helpful at all? It could be full of the guck in the air or dog fur that floats around my yard like clouds.

 

I just looked at my own records and saw that I replaced the water pump in December 2025, about 16,000 miles ago. Was just done at my local mechanic - totally trustworthy but not hybrid specific. So, this is the first summer on that water pump. I will call them and see what brand they would have typically used.

 

Engine water pump. I see the bill, but can't tell the brand of replacement they used. Can call when they open tomorrow.

 

FYI - the shop where it is now, they stock Japanese Gen 3 replacement engines... because of the demand. Apparently Japanese replacement engines are very low miles? They used to retrofit Gen 4 engines in there, but can do these Japanese ones for much less money I guess. Interesting approach.

 

Battery tested as "very weak" for whatever that is worth.