Ford Key fob disable ?
- Thread starter Left Coast Geek
- Start date
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A few wraps of aluminum foil does the same thing
Danm355
Active Member
I've had key fobs for over 20 years and never had to replace a battery.
Yosemite Sam
Active Member
First you have to understand how the "modern day" vehicle key fob works. Most vehicle key fobs use two different
methods to access your vehicle and start it.
The first uses RFID technology that acts as an RF transponder. It never emits a "signal" until it's in close proximity to
an RFID tranmitter (The vehicle). Once the fob is within the RF (radio frequency) zone of the vehicle it is energized and emits
an RFID code that is received by the vehicle's transponder. If the codes match then you can gain access. Please note: the
fob does not require a battery nor does it have to be powered externally, it only activates (transmits) a code when it is in
the near field (usually a few feet) of the vehicle's constantly transmitted RFID transmitter. The fob is powered by the magnetic
RF field generated by the vehicle, its code is programmed by the factory OR the user using the current fob so that the two
can communicate and match codes. The usual RFID frequency is 125kHz, a very low frequency located below the
standard AM broadcast band.
The second method (when you use a button on the fob) transmits an Ultra High Frequency (UHF) RF code to the vehicle on
one of three different frequencies: 315 mHz in the U.S. and Japan and 433.92 mHz in Europe. Please note that this method
DOES require a battery in the fob because it initiates the exchange.
THERFORE, as long as you are not pushing one of the keyfob's buttons there is no battery drain on the fob. None, zip
nada. Once you press a button the fob there is a momentary draw of current on the fob and then it returns to none, zip
nada.
methods to access your vehicle and start it.
The first uses RFID technology that acts as an RF transponder. It never emits a "signal" until it's in close proximity to
an RFID tranmitter (The vehicle). Once the fob is within the RF (radio frequency) zone of the vehicle it is energized and emits
an RFID code that is received by the vehicle's transponder. If the codes match then you can gain access. Please note: the
fob does not require a battery nor does it have to be powered externally, it only activates (transmits) a code when it is in
the near field (usually a few feet) of the vehicle's constantly transmitted RFID transmitter. The fob is powered by the magnetic
RF field generated by the vehicle, its code is programmed by the factory OR the user using the current fob so that the two
can communicate and match codes. The usual RFID frequency is 125kHz, a very low frequency located below the
standard AM broadcast band.
The second method (when you use a button on the fob) transmits an Ultra High Frequency (UHF) RF code to the vehicle on
one of three different frequencies: 315 mHz in the U.S. and Japan and 433.92 mHz in Europe. Please note that this method
DOES require a battery in the fob because it initiates the exchange.
THERFORE, as long as you are not pushing one of the keyfob's buttons there is no battery drain on the fob. None, zip
nada. Once you press a button the fob there is a momentary draw of current on the fob and then it returns to none, zip
nada.
