Trunk Popping by Itself

[vonVeezelsnider]

There's this annoying and pseudo worrying thing the Regal has been doing lately...

I've been noticing a trend where as I'm leaving or coming home and I park next to the thing the trunk is always popped. Of course every time I see this I just open it and close it nice and firm but my brother says that he simply hasn't been using the trunk. Just in case it's simply a hair trigger keyfob I took the batteries out of both of them and sure enough as I'm leaving for class today, there it is nicely ajar again. I also checked that there wasn't some sort of an obstruction in the glove box depressing the button there. Any idea what would be causing this? I'm thinking of disconnecting the solenoid for the trunk release until I can resolve what the problem is.

In addition... there have been some teething issues with the Regal since it joined the fleet in October (perhaps worth mentioning)- Oil Pan Gasket, Front Axle Seal have been replaced and now it looks like maybe the Lower Intake Gasket will need to be done sooner rather than later.

Edited January 18, 2011 by vonVeezelsnider

[SAmadei]

I suppose to be sure its not an electrical problem, I would check the wiring from the glove box button and remote receiver to the solenoid... but my thinking is that a short would not make it pop the trunk, it would stop the unit from working at all. I really haven't heard of too many people having the remote systems activate spontaneously.

Is it just the trunk? Does it just happen at home?

I'm going to go with a different idea... did someone else in the neighborhood get an additional GM car?

While GM may boast of a plethora of remote security combinations, there are a lot of GM cars out there and they do repeat. Perhaps someone has a remote using the same key. I don't know the specs for GM's remote systems, so I don't know the exact chances of this happening. I suppose you could get an idea of the radius involved and just ask around... the remote shouldn't be good for more that a few hundred feet.

I suppose you could clear your remotes and add the current remote back. Perhaps a long-lost remote is the one being triggered.

Its funny you post this problem, as I recently was going to do something like this on purpose... My Bonne remote is getting flaky, and I have a spare "broken" remote for my sister's car. I was thinking of building a FrankenRemote and programming it to my car. Sure, if the cars were together, remote usage would get confusing... opening both sets of doors, popping both trunks...but they seldom are in the same state, let alone same driveway.

Someone who has actually done the remote programming may be able to shed more like on this.

[vonVeezelsnider]

I suppose to be sure its not an electrical problem, I would check the wiring from the glove box button and remote receiver to the solenoid... but my thinking is that a short would not make it pop the trunk, it would stop the unit from working at all. I really haven't heard of too many people having the remote systems activate spontaneously.

Is it just the trunk? Does it just happen at home?

I'm going to go with a different idea... did someone else in the neighborhood get an additional GM car?

While GM may boast of a plethora of remote security combinations, there are a lot of GM cars out there and they do repeat. Perhaps someone has a remote using the same key. I don't know the specs for GM's remote systems, so I don't know the exact chances of this happening. I suppose you could get an idea of the radius involved and just ask around... the remote shouldn't be good for more that a few hundred feet.

I suppose you could clear your remotes and add the current remote back. Perhaps a long-lost remote is the one being triggered.

Its funny you post this problem, as I recently was going to do something like this on purpose... My Bonne remote is getting flaky, and I have a spare "broken" remote for my sister's car. I was thinking of building a FrankenRemote and programming it to my car. Sure, if the cars were together, remote usage would get confusing... opening both sets of doors, popping both trunks...but they seldom are in the same state, let alone same driveway.

Someone who has actually done the remote programming may be able to shed more like on this.

I don't know if it's been happening elsewhere... As for the other car, other remote theory, we're actually the only ones on our street who have a GM car of any kind (neighbors have a Sierra HD and a Yukon which don't have trunk releases) so I doubt it's that. The remotes were cleared and reprogrammed when I bought a new one months ago since the previous owner lost one of his fobs.

It's a real head-scractcher

Edited January 18, 2011 by vonVeezelsnider

[Drew Dowdell]

It doesn't have to be GM and it doesn't have to even be a trunk release.

When I had a Lucerne rental, I parked in the mall parking lot next to a Subaru. When used the Remote Start, the panic alarm on the Subaru went off. When I pressed remote start again, the Subaru's panic alarm shut back off.... I was able to replicate it again right after, so it wasn't like a proximity thing.

[SAmadei]

It doesn't have to be GM and it doesn't have to even be a trunk release.

When I had a Lucerne rental, I parked in the mall parking lot next to a Subaru. When used the Remote Start, the panic alarm on the Subaru went off. When I pressed remote start again, the Subaru's panic alarm shut back off.... I was able to replicate it again right after, so it wasn't like a proximity thing.

Well, perhaps Subaru with its past GM linkage, shares a supplier.

The remotes have FCC IDs, so I'm sure there is some band limitations in there somewhere to keep suppliers from stepping on each other's toes.

Of course, there is also the possibility that someone has build something custom and it "recording" the remote signals and replaying them. Edit: Apparently, this is unlikely on a 2003 vintage.

To isolate if this is a system problem or external problem, I'd disconnect the remote receiver for a few days. Trouble is if that stops the trunk from popping, you can't really test the unit itself without replacing/reprogramming it... and it could still be an external issue.

Edited January 18, 2011 by SAmadei

[SAmadei]

Interesting, so according to this: How Remote Entry Works it looks like any modern fob has a 40 bit "rolling key" and the only synchronization is done by the car holding the next 256 codes. In fact, I'd say that no fob has a key at all anymore, and that instead all fobs have the same set of keys that loop to infinity. Its the sych process that makes the fob work... at least until you hit the fob button the 257th time while not in the car's presence... then the fob will be assumed to be some other fob and ignored. As part of this sync process, the Car and the fobs all need to use the same Pseudo Random Number Generator.

So if you imagine, all the remotes are sharing the same gigantic key that eventually repeats... but each car/remote is only looking at a small portion of that band.

Its also interesting because all the US remotes work in the 315Mhz band. Not sure if that band is subdivided by supplier, etc. though. Thats a pretty big band, and I doubt the FCC would not subdivide it somewhat.

Trivia...knowing that most GM cars can hold 4 fobs, thats 40K of non-volatile memory per car, just for keys and future keys. Don't sound like much, but thats alor for an embedded system on a car.

Getting back to Von's problem... _IF_ this is a remote interference problem, you could solve the problem by unplugging the remote receiver for a few weeks... or by pushing your fob button (not in the presence of your car) 1000 times, then resynchronizing the fob. This would either drop you back in the list of rolling keys or put you ahead of the list of rolling keys enough to break the inadvertent sync you might have going on.

Good news for me, as I can reuse my sister's remote since they never had the same key anyway. I just need to make sure I use the fob 256+ times before the cars end up near each other again...

Bad news... if someone reverse engineers the PRNG (I'm sure someone has by now), you could jump 256 keys at a shot and rapid fire codes out and _someones_ car in a parking lot is going to eventually unlock. You could probably kick out 25K keys a second. 10 million keys in about 6~7 minutes.

[vonVeezelsnider]

So I unplugged the trunk solenoid and then plugged it back in, reprogrammed both remotes again, and took them apart and put them back together again and the problem seems to have stopped for some reason. I'll have to keep an eye on this though.

Weird.