Battery temp sensors activated

Hi all. I've been a long time Priuschat peruser who now needs some help. Hopefully some of you have had a similar issue and can point me in the right direction before flushing an absurd amount of dough at the Toyota dealer.

I've had a 2012 Prius for 9 years and currently at about 290k kms. I bought it in 2015 with 50k and it's been close to bulletproof. I had to replace the heat pump several years ago and that's the most major issue till Fall 2024. It started leaking coolant, which I thought was the head gasket. It sat for about a month, which also killed the 12v (original). I replaced the 12v and, after further investigation, replaced the water pump and thermostat, which seemingly fixed that issue (no more P148F code, no losing coolant).

The very next day (early Dec) I went to drive it and had P0A9E Hybrid Battery Temp Sensor A High, P0AC8 Hybrid Battery Temp Sensor B High, and P0ACD Hybrid Battery Temp Sensor C High all come on and went into limp home mode. The last battery health test I did with Dr Prius back in the summer said the battery was about 68% healthy. And I had Toyota test it a year ago and it tested healthy.

Side note and perhaps related is the fact that I've had a rodent, I think a rat, in the vehicle off an on for the last couple years and actually spotted it running up the back seat the day the codes came on and found fresh feces in the spare tire well and by the 12v.

Any advice or suggestions would be very greatly appreciated. Thank you.

 

Thanks for the reply. I don't mind getting close to the battery. I planned to try that and have a look. It's the middle of winter here in eastern Canada and has been really cold. Looks like some milder days coming so I'll give it a go. I've inspected the high voltage and other wiring coming out of the battery compartment and around the 12v and battery fan but can't see anything obviously damaged. Next step will be to get the cover off and have a closer look.

I'm no Sherlock Holmes, but having all three sensors tripped at the same time having no issues prior in 9 years, and seeing a live rodent scurrying around the trunk area leads me to believe it's a wiring issue of some kind.

 

Interesting. I haven't thought of that. I had a basic Bluetooth obd dongle that worked with Dr Prius. I've used that app as well as Car Scanner and they've read the same. In an attempt to get a code reader that read the INF subcodes I bought the ThinkDiag Mini and used it today to read them again. Same codes. I haven't found a way to read the subcodes and have a sneaking suspicion this model can't do that. But it does say it can generate a freeze frame, which I hope to run tomorrow.