07 prius and I just changed the 12v battery myself, it's been a couple weeks and the cars been turning on and running fine since then. Suddenly since the beginning of this week I've had issues when turning it on. Symptoms: First time starting: no response and the brake will actually push up against my foot. When turning the car on, it'll partially turn on with all the warning lights on. and then I'll turn it off and back on and it'll be fine. But today the car wouldn't turn on at all so I got a JumpStart. Drive around for a bit then park it back at my place. Haven't checked it again but i fear that it won't start again without another jump.
how many miles on her? i would double-check your battery connections, especially where the negative cable connects to the chassis. also check the voltage.
You can check voltage on the battery (see threads how to get into diagnostics mode to check voltage.) A good step is to check voltage beofre you install batt and give it pre-charge if necessary. It takes a really long trip to charge up the 12v if its too low to start with, as the Prius charges the 12v a little slowly.
Changed the 12v because the car battery kept dying often and when I checked the voltage it was only at 9.8v so I decided to switch it out. 104k on it but after I changed the battery the maintenance light was also on but I need to change the oil so I thought it might be that. But thanks for your guys' help, I'll try what you've said and post the results
Maintenance light is just triggered by odometer, basically a reminder. It's not an indication of problem detected.
