OK, I have one for you "techies"....

I was approaching my parked HHR in a large parking lot. When I was about 4-5 car WIDTHS away, I pressed my "Door Unlock" button on the key fob. My doors unlocked and the car next to me, a BMW 325I Convertible, alarm started sounding (appeared to be attached to the horn) . I looked a few seconds and thought, "what the hell", then pressed the "Lock" button, twice out of habit. The alarm stopped. Pressed my unlock button, which again sounded the Bmers horn and unlocked my doors . Opened the door quickly, got in, started my car and put it in gear...doors locked but the Bmer kept on sounding. Pressed my lock button twice on the fob, and it stopped.

Sat around for a little while but the owner never showed up. So, I wrote a note, on a businees card, about what happened and put it on his windshield. Hope he calls.

What, as some people here would say, YALL think??

 

That's a strange one Snoopy!

 

not so wierd... unless i was drunk coming out of apple bees...

i was the only one in a parking lot when i did the same thing, and i noticed that when i pressed MY alarm twice not only did my honk, but so did some other car...couldnt tell which it was..so i did it again and same thing....

could have jacked a nice stereo if i was inclined, but oh well
same freq. i guess?

 

A friend locked his keys in his car, 1987 chevy caprice or somewhere around there. We were joking and I had keys to a winter beater back then. It was a AMC, he dared me to try them, not only did they open the door but the ign key started his car.... go figure!!!

 

Similar thing happened with my father in law.

Him and his friend were the mall. They approached a van that looked identical to theirs, used the key to open the door.

It wasn't until they were sitting in it did they realize they were in the wrong van

 

Ha ! That's my bread and butter....

The remote functions are done with the use of codes (just like a dial locks). There are lots of codes available, but not an infinite number. The problem in this case, is that 2 codes could be close to each other (as in a high % of matching digits), that they work on multiple cars.

See, on the car receiver's side it has to allow for some slack on what it receives, because of weak signals, interference and such. So typically, it will allows an unperfect match to open the doors. It's all a balance act between working only in perfect conditions, i.e. rejecting some valid attempts, and accepting false attempts, i.e. opening up with the wrong remote.

In radio detection terms, you would list the following possible events:

A) Positive detection with invalid remote
B) No detection with valid remote
C) Positive detection with valid remote
D) No detection with invalid remote

The design is meant to maximizes C) and D), but A) and B) cannot be reduced completely to 0 probability, because A & C and B & D are linked together.

In the case of the bimmer, it's possible that it detected that someone was trying to spoof the receiver. Sort of an extra level of protection.

Was that techie enough? I know, I'm a nerd and proud of it....

Yves

 

I had this happen with the garage remote. It was a one of those that the frequency changes after each use. Every once in awhile it would open the neighbors garage!!