FOB is dead -- how do I roll up the windows?

It is supposed to flash, at least on my older Prius, so I suspect the fob battery is still good.

The dead-fob card instructions, or at least the nearest approximation of the AT portions, are correct for my old Prius.

Have you checked the 12V battery in the car? That would be my top suspect.

 

Your 12v battery is probably low. Put a trickle charger on it. If that fails taker it to an auto parts store and have it tested. If it’s bad good luck finding a replacement as they are in short supply many places.

 

99-Cent Only Store sells three ACDelco CR2032 lithium coin cells for a dollar. You can probably find them in other dollar stores as well. Try a jump start for the 12-V battery as others said as well.

 

Even if the battery in the electronic key (key fob) is dead or weak, you should still be able to start the car using the passive RFID tag inside the key, which the car’s power switch (power button) can read; see the procedure on page 691 of the Owner’s Manual (PDF). For battery replacement, see pages 627–629.

 

Of course. It won't start with a dead 12-V battery.

 

Dude, your 12V is dead. NOTHING ELSE WORKS WHEN THE 12V IS DEAD! You can jump start with another 12V battery, but be very careful. A better option is a

 

Instructions for jump-starting are around Page 703 of the owner's manual. You don't need a special device. You can jump-start it from another car's 12-V battery. Just make sure you connect positive (red) to positive and negative to negative and follow the rest of the instructions.

If you have a set of jumper (or booster) cables and a second vehicle with a 12-volt battery, you can jump-start your vehicle by following the steps below.

1. Open the hood. (→P. 585)

2. Remove the engine cover.

Pull up the both ends of the cover vertically.​

3. Connect the jumper cables according to the following procedure:

i. Connect a positive jumper cable clamp to the positive (+) battery terminal on your vehicle.

ii. Connect the clamp on the other end of the positive cable to the positive (+) battery terminal on the second vehicle.

iii. Connect a negative cable clamp to the negative (−) battery terminal on the second vehicle.

iv. Connect the clamp at the other end of the negative cable to a solid, stationary, unpainted metallic point away from the 12-volt battery and any moving parts, as shown in the illustration.

v. Start the engine of the second vehicle. Increase the engine speed slightly and maintain at that level for approximately 5 minutes to recharge the 12-volt battery of your vehicle.

vi. Maintain the engine speed of the second vehicle and start the hybrid system of your vehicle by turning the power switch to ON mode.

vii. Make sure the “READY” indicator comes on. If the indicator light does not come on, contact your Toyota dealer.

viii. Once the hybrid system has started, remove the jumper cables in the exact reverse order from which they were connected.

ix. To install the engine cover, conduct the removal procedure in reverse. After installing, check that the fixed pins are inserted securely.​

Once the hybrid system starts, have the vehicle inspected at your Toyota dealer as soon as possible.

 

Prius Prime is a PHEV, not a BEV, so it can be jump started.

As expected when the 12V battery is dead.

As expected when the 12V battery is dead.

This also won't work when the 12V battery is dead.

 

Yup! Definitely a dead 12V. A dead 12V means a dead car whether it's a gasser, a PHEV like the Prime, or a BEV. (Except in 1 or 2 rare cases with the BEV, iirc.)

As for the fob battery, they are cheap and abundant at grocery store, hardware stores, etc. They only take a minute or less to change.

You'd also need to do steps 3 & 4. But that won't help with a dead 12V which is obviously your situation.

 

Another PP 12v battery bites the dust. I just saw a YouTube video on the dead 12v battery issue on Kia EV6. I wonder when the automaker is going to come to a sense to use the traction battery to start the car and get rid of the 12v battery altogether. Or, is it better to have separate batteries for some profound reason?

 

That's because you really don't want a dead traction battery. Besides, the SOC on the traction battery isn't supposed to fall below a certain minimum to maintain life cycle, albeit lithium-metal batteries with zero excess lithium on the anode (QuantumScape is the only company trying to commercialize one) will change that.

 

Yeah, I know replacing the 12v battery is way cheaper than replacing the traction battery. But, still, the common theme among the carmakers is "let the owner pay for the new 12v battery, while we keep them happy with 10yrs/150kmile traction battery warranty." I just think there are better ways since the 12v battery no longer has to turn the engine like the old cars.

 

I think a good solution would be for the 120-V wall charger to have the ability to charge the 12-V battery. This would not only eliminate the need for a jump start but also extend the life of the 12-V battery by regularly charging it during EV charging. Of course, this assumes that the owner has access to an electric outlet and/or periodically charges the traction battery. I've always found it odd that when the 120-V charger is connected, the 12-V battery is drained instead of being charged. This is a fundamental problem with the Prius Prime, and it is probably the main reason why the 12-V battery is short-lived for many owners, who mainly do short trips, use the accessories a lot, leave the 120-V charger plugged in for extended periods, etc.

 

Agreed. But just to be accurate, charging the traction battery of the PP does charge the 12v battery. Just not consistently enough to maintain the health of the 12v battery. Especially if one does only sporadic charging or keeps the charge cord plugged in for a long time (weeks) after completion of the traction battery charging.

excerpt from my comment on this thread: Hopefully, ultimate 12v battery charging system discussion on PP | PriusChat
EVSE Charging: While the PP is plugged in with EVSE, it seems to have two levels for charging. The first is ~13.5v charging which occurs only during the time the traction battery is actively being charged. I have never seen this active charging occurring outside of the period of the traction battery is being charged, even if the EVSE is kept plugged in after the traction battery charging has finished.