This happened to me whille on a trip out in my Maxima. The alarm sounded and I couldn't turn off. After five minutes of trying to disarm it, I was ready to disconnect the battery on the car when I remembered my wife was also carrying a key fob in her purse. Sure enough, her key fob was the culprit, pressing against something.

 

Could be it's some local interference from where you park your car. Like a indoor or outdoor parking lot. They may be using wireless security cameras. At home I would not rule out some of the newer cordless phones.

Remember the interference problem with some TCH's where the car doors were stubborn to open. This was when parked in very near a convenience stores automatic front door. I think they found they could hold the key up next to the small rubber sensor on the handle and then it worked ok.

A while back I parked next to another TCH at the local Walmart parking lot. I started talking to the owner. He wanted to see my interior color and I offered to show him my MFD mpg reading. He sat in the drivers seat. I was on the passenger side. I had all kinds of trouble getting the MFD in my car to come on. He suggested me to hold my key up next to the sensor button. Then it worked. He said he had his cars TCH key in his pocket. Evidently my car was getting confused with the two signals.

I wouldn't think a garage door opener would work over 4 or 5 houses away.

I have not looked, but you would think that Toyota may be able to lower the cars sensitivity down some for people that live or have to park in a high interference area.

 

I have noticed my trunk open a couple of times. I assumed i had hooked the latch while getting out of the car.

 

So that makes three forum members who have noticed the trunk problem. But I wonder how many more TCH owners have experienced it and blamed themselves.

Perhaps the correct conditions and circumstances have to align for the problem to occur, and for the owner to realize that a malfunction is at fault. If it happens just once over several months, it's harder to recognize the problem. If my experience had been limited to one incident, I would have never raised the issue with the dealer.

But if the problem occurred even for just a few owners, isn't the potential there for it to happen to anyone? I see this as a very real security issue (not to mention the inconvenience of having rain soaking the trunk, as I experienced after the first night of ownership). The only defense is to manually lock the trunk, reducing the value of the SmartKey. My wife, who drives the car to work, is pretty unhappy about the prospect of regularly detaching the tiny key from the fob to lock and unlock the trunk, and she sure doesn't want to do it long term. I see this as a flaw in the SmartKey system. It would be nice to have a regular-sized, easy accessible key as a backup or alternative to the system.

In our previous car, an Accord, a lock by the driver's door could secure the trunk against entry from inside the car. So the key had to be used to unlock the trunk, but never to lock it as with the TCH. I was surprised Toyota didn't use some version of this convenient arrangement, but suspected it was because of incompatibility with SmartKey.

Fortunately, the trunk problem is the only issue I have with this impressive car after a few weeks of ownership. But it's not a minor one, considering the security and inconvenience involved.

 

I would not discount the accidental button press while in the pocket idea myself unless both keys were accounted for and secured first. I've come out to find power sliding door of van open after the kids got a hold of the remotes the night before. I had one car that if I had the remote in my pocket and was working in the garage, I could hear the doors constantly locking and unlocking everytime I moved or bent down. The Toyota remotes aren't as bad as that one, but I have set off the horn alarm in my Sienna twice, and in my TCH once just by having the remotes jammed in tight pants pockets and sitting or crouching or other movement that caused some pressure on the remotes. The trunk button and horn button are slightly raised, so they are more likely to get accidentally pressed then the lock/unlock buttons.

 

I'm inclined to agree with Droid13's analysis on this. However, it is possible to have the remote trunk unlocking function disabled by the dealer if the problem persists and no cause is found. See the attached list, from the TCH Repair Manual, of those things that can be dealer-modified.

Stan

 

Andy: That's useful to know. I tried to simulate an accidental push of the trunk unlock button and couldn't do it. A firm, sustained button push is required on my remote. The dealer also reached that conclusion after initially suggesting the same thing you have. Could I have accidentally pushed and held the button on two occasions? It's not impossible, but my behavior on the two nights in which incidents occurred were no different than any other night when the trunk stayed locked, just standing and sitting in a chair. My wife didn't have her key on her person.

If others who have experienced the problem can recall the key circumstances, that might be helpful.

Stanley: I'm not clear on how disabling the remote unlocking function would help, except to eliminate one possible avenue for interference. The SmartKey would be another. But the manual key, which overrides the remote and SmartKey, is already my means of ensuring the trunk won't pop open unexpectedly. Whether I disable these convenient lock systems or just use the manual key, the result is the same and I feel I've lost part of the features I've paid for.

 

hycambrid — My thinking was that, if it's external interference that's causing the car's trunk unlock system to be spuriously triggered, disabling the trunk unlock system might stop this spurious triggering. I wouldn't be keen to do so either, but it might be one way to stop the mysterious trunk openings.

Stan

 

Unless Toyota did a VERY bad design, it is virtually impossible for external interference to open the trunk.

1) Interference would have to be on the correct frequency.
2) ...Same modulation format as the fob.
3) ...Correct rolling code
4) ...Correct command to open trunk.

What are the chances of that?

I have a friend with a Corvette. He was always unlocking his trunk by sitting on his keys. If you have a bunch of keys on a big ring, it isn't too hard to have the tip of a key dig into the trunk button for a few seconds.

 

It happened again this morning. My wife and I went into the garage and found the trunk open and one other thing, the doors were locked, (we never lock the doors in the garage). When I opened the driver's car door with the FOB in my pocket, a buzzer went off and it continued for several seconds. It was if someone had locked the doors from inside the car and opened them from the outside. Who knows what's going on!