Could the inverter in my 2013 Prius be malfunctioning but no codes show? I'm desperate, my 12 volt battery drained completely while I was gone for 11 days. I had it jumped, took it to the dealer for a new battery, and 4 days later the new battery was completely drained. (No lights, etc. were left on.) Took it back, they charged the battery and tried to get it to "act up" but couldn't. Apparently diagnostics showed nothing. I got it back and the next day the battery was completely drained again. They have now had it for over two weeks and haven't found anything. I volunteered to come drive it for a longer time then I'm sure they are driving it but they didn't like that idea. I've been trying to figure out what could be the problem. No, I'm no techie, just really frustrated. I found out that an inverter charges up the 12 volt battery. If it had an alternator, I'd think it was that but... You would think the techs at the dealership would have the answers, but obviously that is not always the case. I'm hoping one of you techies might be able to help! Sorry this is so long.
You have a parasitic drain somewhere in your system, you need to find out what it is otherwise unhook your battery in the mean time
One way to handle this would be to connect a volt meter and then proceed to remove and reinsert fuses, one at a time while watching the meter. Bear in mind that some electronics such as the alarm and part of the radio need power even while the car is off., but if there's a voltage dip on a fuse that doesn't make sense, that could be your culprit.
Maybe the battery connections are not tight. If it's at the dealer, they should know if the battery has an issue. They would load test it. Then they would check if the dc to dc converter which charges the battery is working when the car is READY. This just seems strange it happened while you were gone for 11 days and it's been normal before that time. Not sure what to tell you, the dealer service dept suppose to be experts on Toyota
