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What would cause all my FOBs to not be recognized

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Old 09-10-2024, 03:50 PM
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Default What would cause all my FOBs to not be recognized

What would cause all my FOBs to not be recognized?

This is a CX5 - 2016

Battery in the FOB's are all good.
None of the 3 FOB's I have will unlock or start that car.
Battery in the CAR is good.

The CX5 is not recognizing any of the FOB's.

Car has 110k miles and has been well taken care of.

 
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Old 09-10-2024, 05:37 PM
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Are all of the batteries the same brand/expiration date? I had batteries that were completely dead and expired, which caused the fobs to not work before and they had to be held near the start button.
 
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Old 09-11-2024, 05:48 AM
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Yes the FOB batteries are Good. I even put a brand new battery in one to ensure this.

The FOBs are all good.
The vehicle battery is good.

BUT the vehicle will not recognize ANY of the FOB's.
The doors will not unlock/lock using the FOB
The vehicle will not turn on with the FOB touching the starter button.

ALL fuses that I checked were good.

What would break that would cause this?
How would I test to see what broke?

Thanks anyone for your thoughts,

 
  #4  
Old 09-11-2024, 07:36 AM
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Maybe the fobs are in "sleep mode". Try this (if you haven't tried it yet):

Take the key fob out of battery saver mode by pressing Lock 4 times until the red light comes on. Then while the light is on, press and hold Lock for 1.5 seconds.
 
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Old 09-11-2024, 10:53 AM
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Thanks. I checked the FOBs are not in sleep mode.

I know most areas of the car but I'm not educated on how the FOB communicates to the receiver (RF HUB) and then tells the BCM (body control module) the FOB is present?
 
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Old 09-11-2024, 11:59 AM
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You may need dealer help, or a good auto electrician.
 
  #7  
Old Today, 08:23 AM
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Have you tested the voltage of the batteries? Anything under 3v is bad.

Does the red LED light up when you press the lock or unlock button?
 
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