Prius v (lowercase v for the Prius v wagon) 2012 Ready Light not coming on

Symptoms suggests a duff 12V battery...

 

Check the voltage on the 12 volt auxiliary battery. If it measures 11.5 or lower at the post's with a digital volt meter I would suggest you fully charge the battery with a "smart charger". If the battery measures 12.3 or higher, then the battery is probably good.



Make certain that you are firmly pressing on the brake pedal when you push the power button. Have someone check to confirm the brake lights are coming on when you press the brake.

Either you have a bad 12 volt battery or the brake light switch is giving your trouble.

If both of those items check out good, then I would start checking fuses, but it sounds like you either have a weak 12 volt or possibly not pushing the brake firmly when pushing the power button.

Best of luck to you and "Welcome to Prius Chat"!

 

If you had just driven it to the dealership, it probably charged the 12V.

If the problem manifests overnight, or after a long parking episode (for example, a full day at work), then it is likely the battery.

The battery diagnostics would be indicative.

 

One additional test you can try, if you're so inclined...
Remove the trim pieces to expose the 12V battery. Put your meter on it and measure the terminal voltages. They should easily fall within the chart DORUNRON provided above. Then, while still monitoring the voltages, turn on the car in ACC mode. Note the voltage. It should not drop below about 12.0 volts. Ideally, it should stay above 12.3 volts. If it drops, then its reserved capacity is severely limited - meaning it is on its last legs. Then, if you're so inclined the next step is to hold down the brake pedal and place the car in IGN mode (where READY light would normally come on). Read the battery voltage again. It should still be above about 12.0 volts. If not, you're battery is indeed limping on one leg. Of course, if the Hybrid system comes on, the battery will read 13.5 volts or higher as the Hybrid system is now charging it.

See if this helps you

 

It's got to be the brake light switch, check that it's not come out of its mounting and check that it's adjusted correctly. Easy check is as mentioned above, get someone to watch the brake lights when you press the pedal. If it was the 12v battery there would be other symptoms.

 

on Gen 2 there were some tricks involving flashing the high beams few times or pressing the nav screen in a special spot a few times to enter "maintenance mode" to allow you to see the current voltage. (nice for people who don't have the skills or equipment required to read their 12v battery's voltage)

Does anybody know if and how to do that in the Prius v?

 

On the UK model, whilst in "READY" or accessory mode, holding the "INFO" button (on the nav) and turning the headlights on and off 3 times does it.

 

Tried to save you a click...