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Phantom Black SXT+ 100th Anniversay
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Discussion Starter #1
I keep getting low keyfob battery alerts from EVIC. Today I got the “keyfob not detected” and my car wouldn’t start. I read a bunch of old threads that there was a known problem. Some said the car will continuously suck power from the fob if stored too close. Thing is, I don’t know what the minimum distance is so this doesn’t happen. I replaced the batteries and check the voltage and sure enough in both fobs they were below 3 V. Now they’re both reading 3.25 or so After replacing the batteries. Can anybody chime in on that distance? Thanks guys

P.S., I realize I can pop off the start button and manually start it but it’s still a nuisance.
 

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once you're ~ 8' away and greater you're out of the range of the antennas (there's several on the car) to detect the fob.

then the CANBUS will go to sleep mode and not communicate with the fob
 

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All I can offer is see how far away you have to be with the key before the car doesn't react to a key button press to lock/unlock the doors then add at least 25% more to that distance.

For example, say the car stops reacting to the key from 50 feet away. Figure 62.5 feet for a minimum distance.
 

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Discussion Starter #6
once you're ~ 8' away and greater you're out of the range of the antennas (there's several on the car) to detect the fob.

then the CANBUS will go to sleep mode and not communicate with the fob
Thanks Hal, I’m going to run a little experiment with this over the next couple weeks. I’ll check back in After I see what happens.
 

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once you're ~ 8' away and greater you're out of the range of the antennas (there's several on the car) to detect the fob.

then the CANBUS will go to sleep mode and not communicate with the fob
My keys hang right near the garage door leading into the house. They are maybe half a car length away and I have only had to replace the batteries once since 2016 when I bought the car.
 

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All I can offer is see how far away you have to be with the key before the car doesn't react to a key button press to lock/unlock the doors then add at least 25% more to that distance.

For example, say the car stops reacting to the key from 50 feet away. Figure 62.5 feet for a minimum distance.
My house is only 40 feet long so I guess I’ll have to store them at my neighbors. LOL. Thanks for the help Rockster.
 

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Discussion Starter #9
My keys hang right near the garage door leading into the house. They are maybe half a car length away and I have only had to replace the batteries once since 2016 when I bought the car.
Exactly, me also. I just can’t understand it. Maybe being a 2014 its actually little different?
 

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My keys hang right near the garage door leading into the house. They are maybe half a car length away and I have only had to replace the batteries once since 2016 when I bought the car.
Similar thing for me - I replaced one fob's batteries a couple of months ago, so it was ~ 4 years.

I rotate fobs at end of each month - that way if one or the other might have a weak battery I'll find out. Also to make sure both are always working properly.
 

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My house is only 40 feet long so I guess I’ll have to store them at my neighbors. LOL. Thanks for the help Rockster.
Just used 50 feet for the sake of discussion. (Actually both my Porsche cars reacted to the door unlock button push from some distance away, nearly 50 feet.)

In the case of your car I doubt it is anywhere near 50 feet.

In fact I had time to think about this and the only time my Hellcat reacts to the key is when the car is unlocked and I am washing it. With me at some places next to the car the car lights come on. Then as I move away the car lights go dark.

If you lock the car I would think the car would not be bothered by the key until you walked up to it and pulled on the door handle. This is the behavior from my Hellcat. After I have parked my Hellcat and locked it when I return to the car the next day there is no reaction from the car until I at least touch the driver's door handle.
 

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Discussion Starter #14
Just used 50 feet for the sake of discussion. (Actually both my Porsche cars reacted to the door unlock button push from some distance away, nearly 50 feet.)

In the case of your car I doubt it is anywhere near 50 feet.

In fact I had time to think about this and the only time my Hellcat reacts to the key is when the car is unlocked and I am washing it. With me at some places next to the car the car lights come on. Then as I move away the car lights go dark.

If you lock the car I would think the car would not be bothered by the key until you walked up to it and pulled on the door handle. This is the behavior from my Hellcat. After I have parked my Hellcat and locked it when I return to the car the next day there is no reaction from the car until I at least touch the driver's door handle.
Understood, did a whole bunch of tests tonight various distances and in the car multiple times and no issues so far with the new batteries in the fobs. As usual, Thanks for all the help. If anything goes haywire I’ll check back in.
 

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once you're ~ 8' away and greater you're out of the range of the antennas (there's several on the car) to detect the fob.
Hal, are you sure on this distance?
remote start, door unlock/lock & trunk pop all work from near 100ft give or take, so I suspect he fob can always talk to the car from much further than just 8ft.
 

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If they are in Faraday pouches, they can be touching the door handle and the car won't see them (know from personal experience). Even with the top velcro open my car didn't see them until I slid the fobs to the opening ;)

A Guy
 

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I thought you had to touch the door handle which then sent out a coded signal that activated the fob. The fob then sent a coded signal back to the car. That's supposedly how the relay attack theft system works. One thief has to touch the door handle while his partner stands next to the house, hopefully with the fob close by inside. IOW neither the car nor the fob continuously sends a signal. That's my understanding.anyway.
 

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I have a 2014 RT Plus, which should be similar the OP's 100th anniversary model.
According to my owners manual...
To lock or unlock the doors, open the trunk, or activate the panic alarm, the distance is 66 feet or 20 meters.
Remote start has a distance of 300 feet or 91 meter.
Passive entry is within 5 feet of 1.5 meters.



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Hal, are you sure on this distance?
remote start, door unlock/lock & trunk pop all work from near 100ft give or take, so I suspect he fob can always talk to the car from much further than just 8ft.
we're talking about the fob in proximity of the vehicle (passive entry) - not pressing any of the buttons on the fob. If the fob is within proximity of the vehicle the fob and the vehicle are in communication - this drains the battery in the fob vs. when its out of range.

for example some people might store their vehicle away and leave the fob inside (example in a secured garage) and they'll find the batteries in the fob tend to wear out quickly

Not transmitting a command from the fob by activating the buttons is what the OP was asking about
 

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I just put my 2014 Challenger and 2017 Grand Cherokee key fobs in a metal cookie tin in my kitchen, not far from the inside garage door. Never had a problem. In fact, you can carry the whole tin up to the car and grab the door handle and nothing happehs. Take the lid off the tin and everything works. Also, FWIW I don't lock either vehicle while in my garage.
 
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