# Open car lock with mobile phone?
**URL:** https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441
**Category:** Factual Questions
**Created:** [November 24, 2004, 7:55am UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441 "2004-11-24T07:55:34Z")
**Posts on this page:** 11
**Page:** 1
### Author:  [@Keapon\_Laffin](https://boards.straightdope.com/u/Keapon_Laffin)
#### Post date: [November 24, 2004, 7:55am UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/1 "2004-11-24T07:55:34Z")
I got an email today, one of those chain ones, and usually I don’t pay attention to those. But this one had an interesting story.
Apparently, if you are locked out of your car without the remote, you just need someone who has your remote to “send” it via a mobile phone. You hold your own mobile phone up to the car’s receiver and when that person presses the button, the signal gets transmitted.
Anyone know if this can be done?
I’ve hunted around and couldn’t find the answer to this.
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### Author:  [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)
#### Post date: [November 24, 2004, 9:20am UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/2 "2004-11-24T09:20:59Z")
Hmmmmm, I suspect that car remotes are infra-red like most other remote control devices, in which case you would not be able to transmit it via a phone.
Waiting for someone to correct me.
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### Author:  [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)
#### Post date: [November 24, 2004, 9:32am UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/3 "2004-11-24T09:32:36Z")
Car remotes are usually RF (not IR), but a cell phone still isn’t going to transmit a signal from one.
First of all, the cell phone you are pointing the remote at will intentionally try and filter off the RF from the remote, since it would cause interference with the cell phone’s operation. If you did manage to couple some of the remote’s signal onto the cell phone’s transmitted RF, the cell tower would either ignore the extra data or, worse, would get confused by it and part of the voice signal from the cell phone would drop out. If any of the remote’s signal managed to get demodulated onto the cell phone’s audio lines, it would come out the other end as audio noise, not as transmitted RF.
In short, it won’t work.
Snopes has an article on it as well.
> **[Will a Cell Phone Unlock Keyless Cars?](https://www.snopes.com/fact-check/remote-possibility/)**
>
> Rumor: Any cars equipped with remote keyless entry systems can be unlocked via cell phone.
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### Author:  [@Keapon\_Laffin](https://boards.straightdope.com/u/Keapon_Laffin)
#### Post date: [November 24, 2004, 1:29pm UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/4 "2004-11-24T13:29:44Z")
Thanks. You saved me and my friends from looking like a bunch of jackasses when we tried this in public.
🙂
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### Author:  [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)
#### Post date: [November 24, 2004, 2:01pm UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/5 "2004-11-24T14:01:57Z")
You can use your mobile phone to call OnStar, which is able to open your door locks remotely. If your car has OnStar. And if your account is current.
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### Author:  [@Balthisar](https://boards.straightdope.com/u/Balthisar)
#### Post date: [November 24, 2004, 11:17pm UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/6 "2004-11-24T23:17:49Z")
> [@ElvisL1ves](#):
>
> You can use your mobile phone to call OnStar, which is able to open your door locks remotely. If your car has OnStar. And if your account is current.
This reminds me – what stops you from just not getting OnStar, then calling and enrolling when you need it for such a silly circumstance (I mean vs. rolling over)? Assuming the car has the hardware. Also, I didn’t have OnStar on my last GM car, so I don’t know the answer to this: how does OnStar get so many customers? If your car has OnStar, does the dealer bury the subscription into the price of the car somehow?
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### Author:  [@DesertDog](https://boards.straightdope.com/u/DesertDog)
#### Post date: [November 25, 2004, 2:14am UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/7 "2004-11-25T02:14:02Z")
[Snopes](http://www.snopes.com/autos/techno/keyless.asp) says no.
DD
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### Author:  [@Joey\_P](https://boards.straightdope.com/u/Joey_P)
#### Post date: [November 25, 2004, 4:50am UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/8 "2004-11-25T04:50:57Z")
> [@Balthisar](#):
>
> This reminds me – what stops you from just not getting OnStar, then calling and enrolling when you need it for such a silly circumstance (I mean vs. rolling over)? Assuming the car has the hardware. Also, I didn’t have OnStar on my last GM car, so I don’t know the answer to this: how does OnStar get so many customers? If your car has OnStar, does the dealer bury the subscription into the price of the car somehow?
You can do that, but it would be rather expensive. Seventeen dollars/mo to get the service that unlocks the doors.
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### Author:  [@Rico](https://boards.straightdope.com/u/Rico)
#### Post date: [November 25, 2004, 5:03am UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/9 "2004-11-25T05:03:22Z")
Most car remotes operate in the area of 200MHz or so.
Your mobile phone is probably capable of reproducing 7 - 15MHz.
Fuhgeddabboudit.
😃
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### Author:  [@SCSimmons](https://boards.straightdope.com/u/SCSimmons)
#### Post date: [November 27, 2004, 1:16am UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/10 "2004-11-27T01:16:27Z")
> [@Balthisar](#):
>
> This reminds me – what stops you from just not getting OnStar, then calling and enrolling when you need it for such a silly circumstance (I mean vs. rolling over)? Assuming the car has the hardware. Also, I didn’t have OnStar on my last GM car, so I don’t know the answer to this: how does OnStar get so many customers? If your car has OnStar, does the dealer bury the subscription into the price of the car somehow?
Look at the fine print at the bottom of their print ads. I believe the typical deal is to include one year’s service in the list price of an OnStar-equipped vehicle. After that year, it’s up to you whether to pay to renew it.
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### Author:  [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)
#### Post date: [November 27, 2004, 2:27am UTC](https://boards.straightdope.com/t/open-car-lock-with-mobile-phone/276441/11 "2004-11-27T02:27:59Z")
> [@engineer\_comp\_geek](#):
>
> Car remotes are usually RF (not IR), but a cell phone still isn’t going to transmit a signal from one.
Yes, the fact that they work while in your pocket should have tipped me off to that.