Forums

RFID

RFID

Is there any area on the windshield on older (2013-2014) models where an RFID transponder will work?

stockboy | 14 June 2019

Is there any area on the windshield on older (2013-2014) model S where a transponder will work?

Mathew98 | 14 June 2019

To the right of the rear view mirror (dotted area).

jordanrichard | 14 June 2019

Place it up against both the headliner and the passenger side of the rear view mirror.

retiredsprky | 15 June 2019

Velcro the transponder to the under side of the cargo cover. The signal goes thru the rear window just fine. Out of sight out of mind.

Captain_Zap | 15 June 2019

@Mathew98

That area worked in my car until I got the windshield replaced.

@retiredsprky

Will give that a try.

TeslaTap.com | 15 June 2019

I may be totally wrong, but I don't think there is RFID in the FOB. I think you can get the FOB to work with a low battery by getting close to one of the antennas (there are qutie a few arround the car).

Here's the test I did - remove the battery from the FOB. I could not find any place that would detect the FOB, including inside the car.

Looking at the spec sheet for the FOB IC, they do have a low battery mode that will work for a while (not stated how long).

EVRider | 15 June 2019

@TeslaTap: This thread is about RFID transponders (like EZPass), not the key fob. :-)

TeslaTap.com | 16 June 2019

@EvRider - missed that! EZpass, etc. are not RFID transponders. RFID is for very short distances, typically 1 cm or so. The Model 3 access card uses RFID and at one time, people thought the FOBs did too.

Really makes it confusing to mix incorrect terminology and I was reading the entire thread as if the OP was talking about a dead FOB using RFID tech and you place it on the windshield (there is a recommended place on the windshield for a FOB that is not working normally).

@stockboy - You might change the title (only you can do that) to "Transponder location".

Daisy the Road ... | 16 June 2019

Both the EZpass and the fob have active RFID transponders. These receive an RF signal and reply with a battery powered transmitter. Some encryption computations are made to allow the original transmitter to validate the transponder.

TeslaTap.com | 16 June 2019

@Daisy - You're right and I'm wrong. I was thinking of passive RFID. I wasn't even aware of active RFID! Ok, back to school for me :(

EVRider | 17 June 2019

Then there are windshield mounted RFID tags that don’t use batteries but have longer range than the passive RFID like the Model 3 key card. I have one of these RFID tags on my Model S to open the gate at my community, but I had to use an externally mounted one (on the headlight) because it wouldn’t work through the Model S windshield (2016 and 2018 models). Note that the Model 3 windshield is transponder-friendly.