2005 Prius probelms

[lls815]

I bought a 2005 Prius with 44K+ miles about a week ago. It's been great and we love it. However, today, we noticed that the smart key wasn't locking the doors after driving the car. When we went back in the car and started the car again, the odometer and the clock reset. This happened again on our return trip home. Could this be the battery or something else? The key stops working for about 10-20 seconds and then when it starts again, the odometer and clock are automatically reset. Any advice would be appreciated since we are new Prius owners!

[925PriusGuy]

We have a 2005 and have never experienced these symptoms... But if the odometer and clock are automatically reset, I'd check the aux. battery in the back. Perhaps one of the cables is loose? Sounds like a battery issue with the car if the clock is getting reset. Good luck with your Prius!

[lls815]

Thanks 925PriusGuy, I'll check out the aux. battery. I hope it's nothing serious. We're just learning about how everything works and we are hoping this is nothing too serious.

[Salsawonder]

Just had to replace my battery. Not the big hybrid, the regular one. I was getting ready to leave and the smart key would not open the doors and nothing was on except the light (dim). I left the car there and took a taxi. The next morning I went out and the doors opened like usual and the power button sort of turned on the car but nothing would work. he speedometer lights started to flash and dim then the other warning lights finally went out except for the check engine light. I got a jump an took it in as I was due for new tires and 45k. $1000 dollars later it was good as new except for the fact that everything in Nav was gone and the service rep did not reset the Nav to the right zone so I got a bit frustrated when I used it for the first time. The customer service people called and were great about listening to my issues. Still got to figure that no brake jobs, no Smog or low gas usage is worth it.

[Patrick Wong]

This does sound like the 12V auxiliary battery is getting weak, or maybe the cable connections are loose.

If you DIY the replacement, the correct battery at the Toyota dealer's parts dept will probably cost ~$160. The correct battery uses smaller-than-normal terminals. Its not easy to find an aftermarket battery that will fit the space without changing terminals, etc.

Also observe battery polarity when replacing the battery or performing a jump. Pls ensure that you do not reverse the polarity or you will do great damage to the vehicle's electronics, potentially resulting in a four-figure repair bill if the inverter is destroyed.

[firepa63]

Definitely sounds like a 12v problem. If you bought the car used from a Toyota dealer, take it back. They usually have some sort of warranty on any used car they sell.

[richard schumacher]

You can check the 12V battery voltage yourself at the jump point under the hood using a voltmeter. You can also use the built-in selftest procedure given here:
Checking 12v Battery Health - Hybrid Car Forums

If you didn't get one with the car, buy a copy of the Owner's Manual for that year and read it. This is not directly related to your immediate problem but it contains much stuff you need to know. (It's also not a model of clarity and does not include things such as that selftest...)

[lls815]

Thanks for the information. I do have the Owner's Manual and have pretty much read it from cover-to-cover. I didn't know how to check the battery with the built-in selftest procedure, so thank you for that. I have called my mechanic and he is going to take a look at it this afternoon. But, now that I can check the battery myself, maybe that will save me a trip.

[richard schumacher]

Good luck! Please let us know how it is resolved.