2005 Prius, Gen 2, code P0A09, Hazard and car symbol with exclamation point

The car's not even broken in good yet but it's at the point year-wise like 20 years old almost where the brake actuator and things are going to start to fail but if you think those things are going to equal a new car better think again in this market even buying a new or refurbed hybrid battery handling the break actuator when it happens and the myriad of other little things that can go wrong you are still way ahead of a I don't even know what $15,000 something another and a payment easily especially if you can do anything yourself this is a pretty easy car to work on as far as taking things off and putting them back on with some basic hand tool seriously You don't need anything special for the most part to work on this car except for a reasonable scan tool if you're going to tackle the brake work and now you can do something with that for like $70 If you think this is costly well you haven't worked on much stuff or anything like that I guess doesn't get much cheaper.

 

The code you have right now is about the circuit that charges your 12 volt battery which runs all of your car except for the electric motors in the transmission and your air conditioning that's high voltage. So your car's inverter apparently isn't charging the 12 volt so now you're running the brand new 12 volt into the ground what you going to want to do here generally is just replace your inverter what's broken is on the bottom of your existing inverter which apparently is working fine The DC to DC converter that charges the 12 volt that circuit has gone bad. Generally it's a pain in the rear end change it it's easier to change the inverter complete they're plentiful they're everywhere junk yards are throwing them away so just grab an inverter from a tow lot LKQ a junkyard anywhere you can get one relatively cheap say let's say $100 or less something like that like I say they can't get rid of these things so happy to take a hundred bucks. Plug that up screw it down and start the car up and check the 12 volt with the car in the ready mode it should show about 13.4 to 14.5 volts with the ready light on and you should be good to go also make sure all of your fuses are good there are some fuses I think that have something to do with charging and all that You want to make sure you don't have any blown fuses they make little doodads to test your fuses right on the car they light up they come in a yellow container made by a company called b u s s and good luck.

 

You would ideally would want to get an '06 to '09 inverter I do believe as that should be the updated part It's the same as 04 and '05 just an updated few pieces inside of it If I'm not mistaken me personally I would probably try to grab one off of an '09 l8 08 something like that. That way there you're getting the last of the inverters with the updates You don't want to take an old inverter like you have a part and do the update to the DC to DC converter it's just a big mess there's too many of these things out there for near free if you were closer to me you could just come by and pick one up and have it because there's nothing anybody can do with it it's going to the trash or on a car which are all now 20 some odd years old and quickly falling by the wayside so there's no market in other words so offer the guy 75 bucks who wants a hundred that's that simple pretty much He's going to throw it away for free.

 

This reasoning is not sound and any conclusions you draw from it are invalid. I'd be very suspicious of any 'professional' who spun such BS.

There is no problem charging the battery in-car and the 12 V is not 'connected' to the hybrid vehicle (HV) battery when the car is off. Even with the car on, the 12 V is not (directly) connected to the HV battery. The only issue with what your neighbor did is if he truly used a trickle charger, rather than a proper 4 to 10 Amp smart charger, is that the trickle charge may not have had enough oomph to make much of a difference in the 12 V battery's state of charge or in any case the 12 V was simply past its use-by date.