otherwise the rear "ashtray" under the vents might be another spot but if it is in none of those and not in the rear seat, the owner hid it on purpose and that will not be found unless you start taking apart dashboards, armreset console.

Apple uses UWB in their air tags so at least the hardware is there in the iphone's since Iphone 11 none se model... Samsung has Galaxy tags... so if there is a software that can be ran on the phone to leverage the UWB antenna on the phones, it might work in getting you closer to this hidden FOB. Of course what you want to do before you start "sniffing" for UWB is turn off the other FOBs.

How?

Very simple, double tap the lock button. Your FOB has a red light that will flash and then long flash indicating that the FOB is no longer in active mode.

this "feature" will disable the FOBs from transmitting actively which disables the "smart entry". Under normal scenario, to test and make sure that FOBs are "off", try to unlock your car with the FOB in your hand. It will not work unless you press the unlock button. In your scenario, this will not work thanks to the hidden FOB. :/

Now with the other FOB still hidden, now you can sniff for it with the appropriate software.


On an Anecdotal note,
I have seen that "stow away" key scenario happen when someone installs a remote start in these cars. They stick the key usually in the glove box but tape it to the top of the glove box so it is out of the way. This allows for the remote start and remote lock.

Good luck! This is a doozy of an issue.

 

Would an easier way not be just to put the known FOBs far away from the car?

Thank you for the "stow away" note. I am starting to think that is exactly what happened. Someone hid the key in the car for whatever reason, maybe thinking it would always start for them before they realized the FOB goes to sleep after X period of non-movement.

 

I have not. I'll try to remember that. Can you post a close up so I know exactly where you mean? (end sarcasm font) Do you honestly think I would have taken out both front seats before checking to see if the key was in the key slot? Do you honestly think it could be there for weeks/months without me noticing? If you posted this as a joke, my apologies for not catching on to it.

 

Brother i am just trying to help you. Sometimes things are right in front of us and we don't realize. It seems to be a logical place where the third key could be left given your situation of the car starting without you grabbing the one from your hook.

 

that is a great first location to look, but come on, if someone has already removed seats, you got to know that was noticed/checked.

 

Because the fob appears to be active especially after moving the vehicle, another option is to use a RTL-SDR dongle with scanner software such as SDR# to look for 415 MHz signals. From that one can check for signal strength as well as triangulate the source location.

A RTL-SDR dongle will cost about $20 if you don't already have one. Thedongles are the same as one uses to feed ADS-B and AIS sites. The software is free.

 

sounds reasonable, but no way I am smart enough to do any of that. I just googled the RTL-SDR and I still don't understand how it would work! Thank you for the suggestion.

 

You might want to give this a shot. If you have a Android phone, download a spectrum analyzer app and search for 415 Mhz.

 

if that spectrum analyzer can do that.. it might be able to do the UWB. Something to test with against the FOBs inside the house.

 

A spectrum analyzer will detect signals on various frequencies, but it doesn't decode them.

 

?

UWB is a frequency range from 2.5ghz to 10ghz. The data of the fob in this instance is irrelevant. The location which appears to be hidden is tbough.

 

@DrJonesLaw

Just thought about this.

If the fob has been barking about a low battery. The more than likely solution is that the fob is close to that place indicated above where you usually insert the fob.

That area does not need the fob to have a battery as it will power it enough to start the car. which means disassembling the center console.

 

Hmmm, so any update on this one OP? Looking forward to hearing where it was and how the "scavenger hunt" is coming along.

 

OP, did you end up finding your key?

 

no. But the only real searching I have done is I removed the front seats to see if it was tucked in there. I strongly believe it is hidden in the dash somewhere and I have not taken it apart to look for it.

I come to this conclusion since I discovered the original owner was car rental place in miami. I have discovered car rental places that allow for drop offs at places other than the original location will hide the spare key somewhere so it is always with the car. The two "standard" hiding places are in the spare tire well and tucked up inside the rear speaker compartment. Some places will put it in the dash somewhere.

 

I just read this thread for the first time. I must say, it's an interesting one. First the mystery of the ability to start the car without a key and now on where this third key could be stashed. I agree that it's unlikely at this point to be an accident to lose the key in the car as you should have found it by now. It could be possible that the prior owner dropped into some place that they could not retrieve it without disassembly to some degree and they decided to just get another one. Another possibility is they intentionally hid it so they could take (recover) the car back if they ever saw it in public. Perhaps their thinking was they could bump or shake the car to wake up the fob and drive away. If the battery is dead on the hidden fob and it's still allowing the car to start then maybe it is close enough to the storage spot or perhaps someone ran a wire to allow the key to be somewhere else and still work without a battery. This is a good possibility if the prior owner was a car rental company and they wanted a way to recover the car. Either way, this would drive me crazy and I would have to pull the center console apart to rule that out. If it is intentionally hidden by the prior owner, I would assume it's not hidden to where a significant amount of disassembly is required. I would be looking in the fuse panel and pulling the under dash panels off to see if it's taped under there somewhere. Basic disassembly needed to run wires for after market electronics would be my focus.

Have you tried to get contact info for the prior owner to see if they could give you information? I'm assuming you have, but just asking for my own curiosity on what the outcome of that was.

 

sorry for any confusion, since the FOB battery died, I no longer have the issue of it being able to start "with no key". I edited a previous comment so you may not have seen it, I have since discovered it was rental car before I had it and I discovered it is not uncommon for rental car companies with multiple locations to hide the second key so it is always with the car. I've already checked the most common places.

 

I wonder if there is a device that can read the RF signals and then locate it by distance (no, I am not talking about relay devices).

 

I see, so the fob battery died, guess we are back to the drawing board now.

 

What an interesting thread...
You best believe I'm stripping my car down to bare metal, plastic granules, and breathing cows if it meant I had a chance of finding a second (or even a third) key for it. How much do these replacement smartkeys cost again? $2000?

The single key I had for my w211 inexplicably became intermittent and then completely died on me. A local "2001 dodge caravan" locksmith programmed me a new aftermarket key for $200. Right after the key was copied it died and never worked again. I would have been in for an "all keys lost" treatment.

I got bored and reminiscent of my beloved w211 (I lost it tragically...) and disassembled the original key. Almost imperceptible amounts of corrosion caused it to fully cease working. Thoroughly brushed it with alcohol, and it began working again. Lesson learned, always have a second key.

I still don't have a second key for my w213.

 

The main concern with that is introducing rattles : (