Unlocking your car with a cell phone?

[Jeremy airjer W]

Along with our paychecks we received a piece of literature with cell phone tips and tricks. One of them was how to use you cell phone to unlock the car. It sounded like a sham but we tried it out on a Dodge Dakota and sure enough it worked.

There are a couple of conditions for this to work. Your vehicle must have keyless entry, both people have to be on a cell phone, and the other person needs to have a spare FOB (keless entry remote). If your keys are locked in the car simple call the person's cell phone that has the spare FOB. Have them hold the FOB next to there phone and press the unlock button while you are holding your phone near the drivers window of the locked vehicle. The door should unlock.

when I read this I was thinking the same thing you are, NO WAY. Seriously, last night we unlocked and locked the Dakota several times from our business office.

Give it a try and post your results!

[LMITOUT]

Leave it to Chrysler to break all the rules of physics. This, the same company that produced the K-car. rofl.

[Hookmaster]

MOPAR!!!!!

[LwnmwnMan2]

 Originally Posted By: airjer

WOW! That sparks some conversation!

So far it seems like Chryslers are the most likely candidate for this to work. I assure you that although our test was no where near scientific we did make sure that we where out of the normal operating range of the FOB. We made several attempts to unlock the truck with no luck before using the cell phones. It did work with the cell phone. I was laughing so hard from shock and disbelief I could barely stand up.

Keep trying and let us know how it went!

It could be just the same reason that if you take your FOB and hold it up to your chin tightly, you'll gain more distance as well.

When I was younger, we used to go to the mall. We could literally set off our alarms in the car from about 1/2 mile away with some of the FOBs by holding it tight against our chin. This was late at night, very few cars and obstructions in the way.

Now granted these were higher end FOBs than most stock keyless entry vehicles give you now, but still it was 5-10x's farther just by holding it up to our chin than "pointing" it at the car.

My parents called me one day because they had gotten the same email, and they said it worked. I asked "where did you try it?". The said at their house.

I went over there and showed them that where they were trying it at, that you could lock and unlock the doors even without a phone.

FWIW, I and my parents are strict Dodge / Chrysler drivers.

Just a little off topic, I still smile each time I see someone walking into a store and quick turn around to "point" the FOB at the vehicle to lock the doors....

[caseymcq]

Tried it on a Ford and a GMC yesterday. It didn't work.

[Black_Bay]

 Originally Posted By: caseymcq

Tried it on a Ford and a GMC yesterday. It didn't work.

You have to do it with a foil hat on too.

[merganser]

Here is proof that unlocking a chevy with a cell phone works. I locked both sets of keys in my truck (long story). I called my wife on the cell phone and within minutes the local towing guy was there with his tools and unlocked my truck.... I didn't even have to hold the phone near the window.... Have a great day everyone!!!!

[Shack]

 Originally Posted By: 311Hemi

Mythbusters already busted it!

Episode 99: "Viewers’ Choice Special 2"

One can unlock a car door by having its remote unlocker frequency transmitted though a cell phone call.

busted

All attempts to unlock the car door via a cell phone call failed. In addition, Grant explained that car unlockers and cell phones operate on completely different frequencies.

I have the link to the video if you want to watch it!!

In this debate, no one has brought up any reason(s) why it would not work (on some models). Above is the closest I have seen.

Saying it’s a "hoax", "don't work" and making jokes about how it does not work, does not prove anything. There was even a guy that claimed to work for a cell phone company and all he said was “it is a hoax”, with out any explanation as to why it would not work. It’s like bringing in a car with a concern to a dealership and having the technician tell you “it’s broke”, with out explaining why “it’s broke”.

I never e-mailed Myth Busters, but did they try this on one car or every model made?

I am thinking it is a Chrysler thing. I have worked with Chrysler dealerships for many years and (I will come out and state this "I can not explain why I feel this way") feel Chrysler does do some stuff that tend to go on a different path with a lot of things with their vehicles. Some good, some bad, but I could see Chrysler being the only company that bought/installed a BCM or keyless entry module that would work. I have seen it, Airjer has seen and others.

I am trying to set something up with a good buddy of mine at a local Chrysler dealership. I would like to do a 10 miles try .

[BigWadeS]

Deadhead that's what I thought too, until I realized by lovely 2yr old daughter was playing with the buttons and changed the code.....

[311Hemi]

I will try it tonight with my 2003 Dodge Ram....this time a few miles away from my house!!!

Shack...they only tested one car.

[DEADhead]

 Originally Posted By: BigWadeS

Deadhead that's what I thought too, until I realized by lovely 2yr old daughter was playing with the buttons and changed the code.....

that's why you keep the factory code someplace where you or your wife will be able to find it

[Shack]

 Originally Posted By: LMITOUT

First of all, key-less entry transmitters typically work in the 300-400MHz frequency range.

A speaker typically can reproduce a frequency of 20Hz (bass) up to 20,000 Hz (treble). Obviously better quality speakers can do better than that on both ends, but that is normal hearing range of humans, so there isn't much reason to design a speaker that exceeds those limitations. The earpiece in a cell phone is far from a high quality speaker, not to mention there is no possible way it's going to reproduce 300 MHz or even anything remotely close.

The mouthpiece is essentially the same as a speaker but works in reverse in that it picks up the sound waves from your mouth and converts it to electrical energy.

Myth: Busted.

Sorry LMITOUT,

I missed your post. Good post!

[Shack]

 Originally Posted By: DEADhead

 Originally Posted By: BigWadeS

Deadhead that's what I thought too, until I realized by lovely 2yr old daughter was playing with the buttons and changed the code.....

that's why you keep the factory code someplace where you or your wife will be able to find it

You guys know you can add another 5 digit personal code to unlock you car. You can add an address or a birth date. There are a lot of features people do not about they keyless entry pad.

[fishorgolf]

Roofer,

Did it work from 30 miles away?

[DEADhead]

 Originally Posted By: shackbash

You guys know you can add another 5 digit personal code to unlock you car. You can add an address or a birth date. There are a lot of features people do not about they keyless entry pad.

yeah I know you can add an extra code, what BigWadeS was alluding to was that his daughter erased his personal (extra)code. I was mentioning to not forget the factory code, which can never be erased.

[Roofer]

 Originally Posted By: fishorgolf

Roofer,

Did it work from 30 miles away?

I thought I had the extra set of keys here for my wife's car and was going to call her after work, but she had the keys with her. So, no I didn't get to try.

[PierBridge]

0-11......still haven't tried a 03 or newer Dodge yet.

I wonder if using speaker phone would work better.

[rockman]

[311Hemi]

All right...had to try it last night so leaving work I called my wife (who continued to explain to me it was a hoax..."didn't you see those emails?"). LOL I said just try it anyways and it did not work on my 2003 Dodge Ram from 5 miles away.

Then I get the "told you so"....

[Trouthunter]

 Quote:

In this debate, no one has brought up any reason(s) why it would not work (on some models). Above is the closest I have seen.

How about offering 1 valid explaination on why it works? It's like saying I passed someone a ham sandwich through the phone...no such technology...if radio waves can "piggy back" on each other, then how come I can't get KFAN out in Montana?...There's enough cell towers to daisy chain that all the way out there...

[beer batter]

 Quote:

It's like saying I passed someone a ham sandwich through the phone

Quite the analogy.

[Shack]

Trouthunter,

I tried, as best as I could. I gave the my best idea at least. If you read back, you will find my post.

I will repost under here what I "thought":

To put this into prospective, I have an older dial radio (tuned in on AM) sitting on the ledge of the window behind me in my office. It is always turned on, but the volume is turned down. I know 5-10 seconds before my cell phone rings that a call is coming in. My radio clicks and pops. It keeps clicking and popping while the phone is in use. Basically, the radio is in between (in the area) of the wireless signal coming into my office (this could be construed as the module in the car/truck) to my cell phone. I guess I should correct my self and say the signal is not going into the receiving phone and then out to the car/truck, but rather the car/truck is in the inbound lane of the incoming wireless signal. The wireless signal going into you cell phone is not just a narrow beam signal, I believe it is wide spread to make sure it finds your little cell phone. The vehicle just happens to be in the wide beam coming down or at the phone.

I feel the same is for the transmitting end phone. When the button is pressed on the fob, a wide wireless signal/frequency is blasted in every direction in a circle type patter looking for a receiver or a receiver path (in a parking lot, when you hit the panic button to find your car, you do not have to point the fob right at you car). It finds the out going signal transmitting up and away from the phone. I do not believe the remote fob signal goes into the phone and then out, but rather meets up with out going signal from phone and threw the sky and passes into a Chrysler remote module.

At least "I" tried to give a theory.

Some higer up(s) in this forum said it works, I have seen it work, but will see what happens.

Limitout did give a good explanation of why it would not work and I did make a correction for this. I missed his post.

[Shack]

Deadhead,

I questioned this, because on late model (lets say 1996 on up) you can add up to 4 or 5 different personal codes. To erase your personal code, you would have to punch the factory code in and hit the 1/2 button, enter another 5 digit code and start that process over 4-5 different times. It would be impossible, unless the battery was disconnected for a period of time. I guess with kids, nothing is impossible .

What I know of the personal code’s, if you fill up the allotted amount of personal codes, it startes the newest by erasing the oldest. I have never tried this in person, but I have come to believe this is true. I could be wrong.

[DEADhead]

shackbash, thanks for the info, I didn;t know you could put in more than one personal code.

 Quote:

It's like saying I passed someone a ham sandwich through the phone

funny stuff. So far I haven't heard any cases where this would work on a Ford vehicle. And only sometimes on late model dodges. Why are only certain people able to get this work on a dodge, while other's aren't?

[Macgyver55]

 Quote:

Why are only certain people able to get this work on a dodge, while other's aren't?

They're standing closer!

[doughnut03]

"There was even a guy that claimed to work for a cell phone company and all he said was “it is a hoax”, with out any explanation as to why it would not work. It’s like bringing in a car with a concern to a dealership and having the technician tell you “it’s broke”, with out explaining why “it’s broke”."

So here it is...

Key FOBS operating bandwith:

France: 224.5mhz

Italy, Australia, Japan, Canada and the USA: 315mhz

UK and Ireland: 418mhz

Europe: 433.9mhz

Cell Phone operating bandwith:

In the US, TDMA was found primarily on 800 MHz and 1900 MHz

In the US, CDMA uses the standard 800MHz and 1900MHz.

In the US, GSM mainly operates on 1900MHz.

With a cell phone, packets of data are sent randomly across the width of the channel and reassembled by the network at the other end so the bandwith basically jumps around all over the place.

IT DOESN'T WORK BECAUSE THEY OPERATE ON COMPLETELY BANDWITHS. LIKE TRYING TO LISTENING TO FM RADIO ON THE AM SETTING.

[cylinder]

I don't think it matters that the key fob and cellphone broadcast on different frequencies-- if it did, there would also be a problem with human voice (at roughly a few hundred hertz)on the cellphone channel. What does matter is that the microphone and speaker of the cellphone aren't made to pick up or reproduce the fob's frequency.

As a previous poster said, even the highest quality speakers in a home stereo have a limit of around 16hz-20khz; a cellphone speaker's range is much less than that because it is optimized for human voice. It isn't able to reproduce frequencies in the range of 300 mhz.

[Surface Tension]

I haven't tried the cell phone experiment. To do so I'd have to incorporate my wifes help. I don't need that aggravation.

I'm going to try a silent dog whistle in private. That way if it doesn't work no one will know but me.

[Scott K]

" I haven't tried the cell phone experiment. To do so I'd have to incorporate my wifes help. I don't need that aggravation."

So true!! I thought about giving this a try , but then I would need to explain to my wife why I was doing it, and where I heard of it, then she would tell me that I waste way to much of my time on the fishing site! And that isnt true!