2009 Prius Error Code P0a80 - Check Engine Light has Since Disappeared

Yes keep driving If you have a friend that messes with cars regularly you can lift up the rear tray and get to the battery and do some bolts and lift up part of the silver cover and just look at the bus bars and nuts on your car there's going to be a lot of frosting if you want to call it corrosion the white stuff that grows on battery terminal positives a lot things like that are going to be showing I'm pretty sure and your battery is what 13 years old whatever it is I just went through the same thing with my 09 about 10 months ago maybe a slightly longer paid $14.95 or right near that for a new Toyota battery I didn't fool around with any of the remanufactured business for this model. Seeing a lot of green and everything running good since

 

good thought. The battery may be sketchy though and sitting might have dropped the voltage below parameters.
Have the 12 volt load tested at auto zone in the meantime

 

Exactly . You can buy hybrid battery for about 1600 now I think . It's an easy change out with very basic hand tools that most everybody has your neighbor yourself somebody that's more of a pain to take the plastic panels out of the trunk to get at it than it is to do anything else you'll need to watch a video You're going to take the front end off your battery it's not anything energized generally and move it to the new rack of cells there are a gajillion videos all over the web

 

It is not unusual for a P0A80 code to be "on again- off again" if one or more HV battery modules are JUST barely at the threshold where the ecu detects a fault.

As the battery deteriorates, lights will come on - stay on. MPGs go down, you might notice the "battery gauge" on the center display (MFD) goes up and down more quickly, reduced performance and louder engine operation (more RPMs).

Eventually it will set a P30xx code - "battery block xx becomes weak" and operation will be very limited.

There MIGHT be a fault (corrosion) with the wiring or battery ecu that monitors battery voltage (but that usually sets other codes).

A 12V battery is a "minor" expense in comparison. It's a consumable item that will need replacement periodically. Depending on the existing 12V's age and what tests were done, I could see one place saying "it's ok" while another says "replace it".

Personally, I replace a 12V at 5 years- period. Some climates are tough on batteries, and having the car start when I want it to is more important to me than "saving a few bucks" and waiting until it fails.

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