Key fob battery life?

:
2013 CX5 Touring
I have only owned my CX5 for 7 months, and when new my key fob would reach 100 yards easy. Now it has trouble at 20 feet. What kind of battery life are all of you getting? At least I think it is the battery. I have yet to replace it. But my spare key still works great.
 
Just replace the battery, takes seconds to open it up.
Remember, these fobs have a radio in them that's constantly broadcasting so the car can detect it and let you start the car.
 
I love my CX5 but I wish it just had a regular 'ole damn key.
It's so easy to get a copy key made when you have a regular key
How can I even copy the hidden accessory key-fob key?
Most importantly....
How can I ever make a hide-a-key and keep it attached to the car?
 
The car can't lock with the fob inside, and the key that can open the door can't do anything beyond that.. So what purpose would a hide-a-key have?
 
Most importantly....
How can I ever make a hide-a-key and keep it attached to the car?

I don't worry about it. I just keep my keys in my pocket and they always seem to be there when I need them. 30+ years, no problem.
 
actually you can lock a fob inside if you use the lock button on the other fob. The car will then ignore the signal from the locked-in fob until a button is pressed on it. So you could hide a fob somewhere inside the car and put the key out of it into a standard hide-a-key holder.

from the manual:
Key Suspend Function
If a key is left in the vehicle, the functions
of the key left in the vehicle are
temporarily suspended to prevent theft of
the vehicle.
The following are inoperable:
- Starting the engine using the push
button start.
- (With the advanced keyless function)
Operating the request switches.

To restore these functions, perform any
one of the following:
- Press a button on the key which has
had its functions temporarily
suspended.
 
Just replace the battery, takes seconds to open it up.
Remember, these fobs have a radio in them that's constantly broadcasting so the car can detect it and let you start the car.

Are you sure about that? That would be very poor design... I would guess that the key fobs have some sort of RFID chip. These are passive, and use the energy from an external emitter (in this case the car) to answer back, so they don't use the battery at all. The only time the fob battery would be used is when you would actually press the buttons on it.

So in this case, the car yould be constantly broadcasting, but it has a way bigger energy reserve than the fob!
 
It has both. In the manual it has instructions for how to start the car if the battery in the key is dead using the reader in the push to start button on the dash.

If the engine cannot be started due to a
dead key battery, the engine can be started
using the following procedure:
1. Depress the brake pedal (automatic
transaxle) or fully depress the clutch
pedal (manual transaxle).
2. Verify that the push button start
indicator light (green) flashes.
NOTE
The push button start indicator light (green)
will flash even if the push button start is
pressed before depressing the brake pedal
(automatic transaxle) or the clutch pedal
(manual transaxle). If the clutch pedal is
depressed (manual transaxle) or the brake
pedal is depressed (automatic transaxle) under
this condition, the engine can be started by
resuming the procedure following this.
3. Touch the push button start using the
backside of the key (as shown) while
the push button start indicator light
(green) flashes.
Key
Indicator light
Push button start
4. After the push button start indicator
light (green) changes to full
illumination, press the push button start
with your finger
 
Are you sure about that? That would be very poor design... I would guess that the key fobs have some sort of RFID chip. These are passive, and use the energy from an external emitter (in this case the car) to answer back, so they don't use the battery at all. The only time the fob battery would be used is when you would actually press the buttons on it.

So in this case, the car yould be constantly broadcasting, but it has a way bigger energy reserve than the fob!

The owner's manual has specific instructions on how to start the car if the battery in the fob is dead. You need to hold the fob against the start button. That would indicate the presence of a passive RFID that can react to energy from an emitter in the car, even with a dead fob battery. It's possible that the fob does not broadcast all the time but might broadcast a reply when it detects a signal from the car.
 
You are right KenMO, I remember reading that in the manual... That would mean that the RFID chip might be too weak to be detected by the car unless very close to the start button. So the battery in the fob might be used to boost the signal, but only when responding to the car, and that could use up a bit more battery than with normal fobs, but enough to get the range down from 100 yards to 20 in 7 months?
 
I have a physical key hidden outside the car. I also have a third spare key fob wrapped in tin foil in with the spare tire. I travel for a living and refuse to be stuck outside of my car again at 4am not being able to drive home.with the fob wrapped in tin foil you can stand next to the car and it won't recognise the fob.
 
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Well I am planning to run by the dealer this weekend to see if they can give me an answer. I will post up what they say, and all the information I find out about how the fob actually works.

So no one else has had any issues like this yet?
 
I had a locksmith make me a key so I could get into my locked CX7. The naked key does not have the transmitter so I can;t start the vehicle but, if I lock my keys in the car, I can get in. I keep the naked key in my billfold. I had to use it twice in 6 years and much easer than any other way. Ed
 
I have a physical key hidden outside the car. I also have a third spare key fob wrapped in tin foil in with the spare tire. I travel for a living and refuse to be stuck outside of my car again at 4am not being able to drive home.with the fob wrapped in tin foil you can stand next to the car and it won't recognise the fob.

Very good information! The Tin foil idea works huh? So you had a physical key made or did you use the one from your spare Fob?
 
The car can't lock with the fob inside, and the key that can open the door can't do anything beyond that.. So what purpose would a hide-a-key have?

The purpose is as follows: Let's say I lose my key fob and I'm far from home. I could use my physical hide-a-key to get into the car and then access my hidden key fob to start the car.
 
Haha tinfoil. Sorry, can't help but think about tinfoil hats. I'm assume aluminum foil works as well? If so that's a great idea to hide the spare on the car instead of having it sit uselessly at home.

Wait, is there a need to wrap it? If we leave the spare in the car hidden, it'll get disabled, but once you get in the car with the physical spare key, can't you just reactivate the spare fob by pressing a couple of buttons?
 
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I had a seperate regular old key made that costed about $10.
Yes, wrapping it up just assured that it wasn't recognized. To reactivate you just press any of the buttons.
 
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I had a seperate regular old key made that costed about $10.
Yes, wrapping it up just assured that it wasn't recognized. To reactivate you just press any of the buttons.

What would be the reason to keep it from getting recognized though? Car sense the key, disables it, we reactivate it later once open the door with spare key.
 
Yes. I wanted there to be no question to me, the Wife, or anyone else that might happen to find the hidden FOB that it stays in the car until needed. I also put the foil wrapped FOB in a ziplock bag with the words "leave in car" written on it.
 
I had a seperate regular old key made that costed about $10.
Nice!
Is there a particular place (or key blank) used to get the physical key made? My local Home Depot could not make it because they said it was "irregular".
 
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