There have been a couple of incidents where the key fob has not been detected by the car, even though it is in the car. When it did this, I also noted the unlock button on the fob didn't work. It only does it a couple of times then all of a sudden it seems to work. There is no message for a low battery (it's not that old). Any ideas?
How old is the battery/fob? The battery only lasts about 2 years on average. Another possibility is that something is interfering with the RFID signal, most commonly a cellphone. Keep your cellphone or any other radio device separate from the fob. SCH-I535
And make sure you don't also have a FOB with you from a different vehicle that uses a similar "smart key" technology. If nothing else is found, I'd be tempted to replace the battery. They are cheap.
The Fob is the same age as the car, 2010. The key may have been in the same pocket as my cell phone, so that could be it. The battery is only about 6 months old.
Try to keep your fob in a separate pocket from your cellphone. I clip my fob on my beltloop using a small carabiner type clip.
If you get a 'key not detected' message on the MFD, while driving, it is often a completely non-obvious warning that the hatch is not securely shut. Even if the hatch seems closed, open and firmly re-close it. This fix applies only if you get the above message on the MFD while driving. Other symptoms, such as buttons not working or inability to open or start because it can't read the key, likely stem from battery or interference issues.
I agree with the suggestion of FOB being close to cellphone. It happens to me when my phone is on my belt and the FOB in the is in the pocket very close to it. And only then. Once the FOB's battery went to be flat I've got the message on the display "Key battery low".
Thanks guys. I think it must have been the cell phone. I have been keeping them apart and haven't seen the message since.
I spend a good part of my day with key fobs from two separate 2010 Prii in the same pocket. I started getting that message when the battery in one fob started going dead...