Strange OEM Key Fob Behavior

[jgruberman]

My key fob unlocks, locks, and remote starts my truck from an average distance.

However, when I get close to the truck to put my hand on the handle to unlock it automatically, it does not work.

Also, when I get into the vehicle and try to start it, it says key fob not detected.

It's clear that there is some issue with the truck detecting the proximity of the key fob, but I have changed out the batteries twice and recently tried to get it to work correctly.

Given that I can comfortably assume it is not battery related, what is the next logical step for troubleshooting this?

I've never had to troubleshoot the proximity of the key fob, so I'm not sure what is involved and what could be defective.

I appreciate any help you can provide.

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[watersupply189]

I have the same issue with the fob on my 2019 Charger.

I changed out the battery, and still a hit or miss.

I ended up swapping it out with the spare key that came with it.


2016 Ram Laramie 3500, G56, 6.7, CC, 4x4

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[AK Bob]

My key fob unlocks, locks, and remote starts my truck from an average distance.

However, when I get close to the truck to put my hand on the handle to unlock it automatically, it does not work.

Also, when I get into the vehicle and try to start it, it says key fob not detected.

It's clear that there is some issue with the truck detecting the proximity of the key fob, but I have changed out the batteries twice and recently tried to get it to work correctly.

Given that I can comfortably assume it is not battery related, what is the next logical step for troubleshooting this?

I've never had to troubleshoot the proximity of the key fob, so I'm not sure what is involved and what could be defective.

I appreciate any help you can provide.

Sent from my SM-S908U using Tapatalk

Great question; I would first try with a different remote key fob to eliminate that possibility.

Unfortunately, there's not a lot of information available on this system.

I have attached what I could find from Mopar Tech Authority.

There are sensors in the door handles that communicate with the Radio Frequency Hub Module (RFHM) via CAN Bus.

The RFHM is located behind the back seat and has four antennas, one in each door, left front and right front, behind the back seat, and the passenger side dash area.

If you have a scan tool capable of reading the RFHM for trouble codes, that would be my next step.

As stated in the attached information, the RFHM is not repairable, so it would have to be replaced if no module input troubles were present.

Hopefully, this will help answer some of your questions, and others will also chime in.

RF Hub.pdf

Passive Entry Diagram.jpg


2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, Fuel Filtration Kit, and 50 Gallon Aux Fuel Tank.

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[egolsen]

I’ve got similar randomness to mine.

Also have changed out the batteries.

Mine won’t unlock if I touch the drivers door, but passenger side works every time?

Maybe the door handle not detecting?

One remote works consistently for lock and unlock, but the other is random.

Considering replacing 1.

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[CrazyTrain]

Mine, too, is random with those symptoms, but I have determined that it happens most often when I have multiple fobs in my pocket.

On random occasions, I usually have my car fob with me, camper fob, etc.

I ensure they are in separate pockets, which seems to help.

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[Bufkin]

I as well.

I carry a magnetic money clip billfold that found that the magnet causes some interference with the fob, but still run into the driver's door not unlocking, but the passenger will do its job flawlessly.

The only fix that comes to mind would be swapping the handles to see if that fixes the problem or if it is indeed the transmitter.


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[jgruberman]

I have been unsuccessful in diagnosing the issue so far.

Sometimes the remote start won't activate from a distance.

However, I can push the unlock button, and the doors will unlock from a distance.

Once I get into the truck and try to start it, it says key fob not found.

I have to repeatedly mash the unlock button, which usually works while pushing the ignition start button.

If I'm lucky, whatever signal is coming out of the remote will coincide with the vehicle detecting it when it's trying to start, and the truck will start.

To troubleshoot at this red light I am sitting at, I opened the driver's door and closed it quickly, and now my dash says that the key fob has left the vehicle.

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[AK Bob]

I have been unsuccessful in diagnosing the issue so far.

Sometimes the remote start won't activate from a distance.

However, I can push the unlock button, and the doors will unlock from a distance.

Once I get into the truck and try to start it, it says key fob not found.

I have to repeatedly mash the unlock button, which usually works while pushing the ignition start button.

If I'm lucky, whatever signal is coming out of the remote will coincide with the vehicle detecting it when it's trying to start, and the truck will start.

To troubleshoot at this red light I am sitting at, I opened the driver's door and closed it quickly, and now my dash says that the key fob has left the vehicle.

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Did you confirm this issue continues with your spare remote?

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[jgruberman]

Did you confirm this issue continues with your spare remote?

I only have one remote.

However, if there is such a replacement I can purchase, program and test with then I am open to that.

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[AK Bob]

I only have one remote. However, if there is such a replacement I can purchase, program and test with then I am open to that.

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The remote is the best place to start and most likely to be the problem as it is susceptible to the most wear and tear.

You will most likely need to go to a dealership to purchase and program the new remote.

Be prepared to pay around $300.

Keep the spare key from your old remote as they charge extra for that.

Our local “Batteries Plus” stores have recently started selling and programming remotes and keys but last I checked they couldn’t get our remotes.

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