That's probably the most typed phrase in all of PriusChat. What exactly does it mean? I don't have a load checker, so I can't check the voltage under load. Assuming the Prius has been sitting a couple of days (not fresh off a drive), what would you like to see the voltage at?
i checked mine regularly. one day it was 12.7, the next, it was 4.0 at 7 years, i figured it was going to be good for a few more. without a load tester, it may not make sense. if you can find the thread, toyota has a headlight test that might work. static voltage check, than voltage drop over time with headlights on. a simpler and more versatile solution may be a jump starter.
For cases where one day it's 12.7 and the next day it's 4.0 V, I would check in the dark the next day after charging it back up. Something drained that battery. The Toyota instructions from Tech Info are pretty easy to remember, just the voltage ranges are somewhat in question: After driving turn off the vehicle or if charging obviously disconnect charger. Run the high beams for 30 seconds. Measure voltage at the terminals: (Off the top of my head which could be off) 12.5 V and up is a good battery 11.0 - 12.5 V recharge and retest less than 11.0 V replace I had a battery that kept falling under recharge and retest by less than a volt. I ended up replacing because my elderly parents 85 + use the car and didn't want to risk stranding them. moto g(7) power ?
(1) turn on the car without pressing on the brake pedal; (2) hold down the “Info/Apps” button while turning the lights on and off 3 times while reciting the alphabet backwards*; (3) when the “Service Menu” comes up press “Menu”; (4) hit “Function Check/Setting”; (5) press “Vehicle Signal”. Click the power button on again to put a load on the system to see if the voltage drops further. * reciting alphabet is optional
