The Toyota key fob is sometimes called a Wireless remote or electronic key. In this article, we will refer to them as key fobs.
This article discusses 5 reasons your Toyota Prius key fob is not working and its potential fix.
Remote Connect Service Expired
Many features on the Prius key fob are now connected to a paid subscription named “Remote Connect.” With the purchase of every Prius, Toyota gives 1 year of free subscription to this package.
Remote Connect has the following features:
- Remote engine start.
- Remote engine stop.
- Remotely control windows, doors, horns, and emergency lights.
These features can also be controlled through the Toyota app.
However, Toyota has tied these features with the key fob. Thus, if you don’t pay the subscription price, your key fob will stop working after the free subscription expires.
Thus if your Prius key fob isn’t working — such as remote start and stop — probably it’s due to the subscription expiration.
Unfortunately, currently, there’s no workaround. You have to pay to enable this feature for your Prius.
Toyota currently charges $8 per month or $80 if you pay for 12 months for the “Remote Connect” feature. If you subscribe to this package, your key fob will work again.
Key Fob Battery is Depleted
The Prius’s key fob typically lasts 2-3 years. However, depending on use, the key fob can operate longer.
If the key fob battery is dead, your key will fail to unlock, lock, or start your Prius. If you have been using the key fob for a time, you can quickly tell whether the wireless remote control’s battery has been depleted.
At the end of the battery’s life cycle, the key fob’s operational range will be reduced significantly because the battery will fail to create a strong electronic signal. Sometimes, the operational range will be less than 4 feet.
At the end of this article, we have given a step-by-step guide to changing the key fob’s battery.
Check The Other Key
Every Toyota Prius comes with two key fobs. If your one vehicle key isn’t working, please try the other one. It will help us isolate the issue.
If one of the key fobs isn’t working, the problem is specifically with the key. But if both key fobs won’t work, then the problem is somewhere else, probably with the Prius’s ECU.
Check the “ECU-ACC” Fuse
There are two fuse boxes in a Toyota Prius. One is inside, and another one is outside in the engine compartment.
Open the fuse box that is under the steering wheel. The fuse cover has a diagram, and look for the “ECU-ACC” fuse. It’s a 7.5 Amp fuse that powers up all the electronics that control the smart key system.
If the fuse is blown, please replace it with a similar amperage fuse. Your key fob will start working after you change it.
While purchasing new fuses, remember that these are Low Profile Mini Blade Fuses similar to this one.
The 12V Battery is Dead
Please check whether the 12V onboard battery in Prius is depleted or not. If the batter gets depleted or has low voltage, your key fob will not work correctly as the 12V battery will fail to power the necessary electronics.
Batteries with low voltage will do weird things. If your 12V battery is older than 36 months, and you are having issues starting the vehicle engine, please change the 12V battery. The low voltage is corrupting the onboard computers.
Moreover, the 12V battery terminals will oxidize over time and will fail to provide proper power to your Prius’s electronics. If you see a lot of white oxidation on the positive or negative battery terminal, please clean those with a wire brush.
Once you change or clean the 12V battery, the key fob should work without issues.
Key Fob is Damaged
The keys on the key fob can get damaged by repeated use. If the button fails to make contact inside the circuit, it will not work.
In this case, however, you must purchase a new key fob from a Toyota dealer and pay them to reprogram it. Reprogramming a genuine Prius key can cost up to $1500. It’s a ripoff, but we have no recourse but to pay it as a customer.
How to replace Prius’s Key fob battery
Changing the key fob battery in the Toyota Prius is straightforward. You can do it at home, and it takes 2 minutes.
At a Toyota service center, they would charge you more than $110. Sometimes, they will ask you $550 to change the battery and reprogram it.
Items needed to change the battery —
- Small Flathead screwdriver
- Lithium battery CR2032
Toyota Prius key fob uses a CR2032 coin battery. You can buy these batteries at a very low price at Walmart or Amazon. Here’s an example of these batteries on Amazon.
Toyota Prius comes with two types of key fobs —
- Smart key system
- Key fob without smart key system
The following steps to replace the battery are for keys with a “smart key system.”
Release the lock on the wireless remote and remove the physical key.
With the help of a small flathead screwdriver, remove the key cover. To prevent damage to the key, please cover the tip of the screwdriver with tape or with a piece of rag.
Remove the battery with the help of the screwdriver. While removing the battery, look at how the battery terminals are placed.
Please be careful about not bending the battery terminals.
Install the new CR2032 battery in the key fob and reinstall the key cover.
Replacing the battery on the Prius key fob without a “smart key system” is the same as above. The only difference is the first step, where you have to open the key cover from a corner, as shown below.
When you change the key fob battery, you don’t need to reprogram it. The locking codes are stored in the Prius’s computer’s memory. This memory is not erased due to battery depletion on the key fob or in the vehicle.
If your key fob still doesn’t work after changing the battery, you don’t need to reprogram it. The problem could be somewhere else.
The key fob reprogramming is only necessary if your onboard vehicle’s computer got a hard reset somehow — such as the 12V battery dead for a long time — and all the memory got erased.
Prius key fob not working after battery change.
The key fob’s coin battery lasts a long time. However, over time the electrical battery contacts corrode and become loose, especially in humid climates. Thus, if the key fob stops working after changing the battery, please open the key again and look at the battery contacts.
If the contacts are flat or loose, take a screwdriver and bend the terminals. If the battery is loose, your key fob will work sometimes, and other times, it won’t.
Visit your Toyota Service Center
Unfortunately, if none of the solutions works, please visit your local Toyota service center. They will charge you a lot of money, but at least they will probably be able to fix your problem.
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