1998 Sienna Doors Lock By Themselves

[docadar]

This problem is getting out of hand. This morning my wife drives down to the end of the driveway, gets out of the car (it's still running) and all the doors lock. She has to get a spare key to open the door.

While we are driving the doors will lock by themselves, and continue to go through the lock routine, even though the doors are still locked. The other day this locking problem happened 15-20 times in about 5 minutes.

The button on the remote is not stuck (we took the batteries out of both remotes just to be sure). Also the car is not supposed to lock with the keys in the ignition...right???? I remember when it was new if the keys were in the ignition and the door was locked they would unlock when the door was closed...I think.

I've called 2 Toyota Service centers and no one has heard of this. There seems to be no mention on the web about this particular problem, and searched for all Toyota, and all Camry's and Sienna's.

It's almost as if the radio frequency receiver in the car for the remote lock/unlock is receiving a signal all the time to lock the doors...even though there is none. Or that receiver is failing and sending the signal to the controller to lock the doors.

I really don't want some technician to spend hours looking for a problem which until it happens he won't find.

Can anyone shed any light on the cause of this and any possible remedies I might try.

TIA

docadar

[vcheung]

I have a similar problem on my 2000 Sienna except it's randomly unlocking itself (instead of locking). I did a little research and some saying that the Sienna security/locking system is very sensitive to the main battery so I replace a new one, but it didn't fix it. Any suggestions ?

[N3wbie]

My problem is very similar on a 1999 Sienna, and after unlocking the car and oppening a door before 30 seconds pass, the car still locks itself back up. I also noticed that the interior lights are no longer coming on when I unlock the vehicle. Anyone have any idea what's causing all this odd behavior, and how to rectify this problem? Thank you in advance for your help.

[praniw]

OK, I had this problem too and I fixed it. I took my van to the dealer about 6 times because the van kept locking my family in the car! This was scary in hot Texas weather. Once I was locked in with the kids and my husband was outside, and he couldn't get us out and we couldn't get out either! It would happen randomly, but eventually the car would "decide" to set us free! Then we would hear the locks clunck and the doors would then open. Here's the fix: The security system harness is an item added to the car kind of "aftermarket", meaning Toyota didn't design it to go with this car specifically. It is not well shielded, and when electro magnetic interference influences it, it will actuate. Tell the dealer to replace the security system harness. The new ones are shielded better. This WILL solve the problem.

[praniw]

PS, I found a very small clue on how to fix this problem on the internet. I told the dealer what to do. As I recall, it was a very obscure Toyota service advisory (or what ever they call it when it is just under the level of a recall). Try the National Highway Traffic Safety Institute website. Look up your car. That may have the advisory. Anyway, Toyota DOES know about this problem even if your dealer doesn't. But it is next to impossible to figure out. I'm a civil engineer, not a mechanical engineer, and it took me forever to figure out the solution to this problem.

[msimmons24]

Did the repair you mention for the doors locking themselves really solve the problem? I've called the dealership and they act like I don't know what I'm talking about. I hope you see this message and will respond. The doors are driving me nuts. Going down the highway the doors keep locking incessantly.
Thanks in advance.

[praniw]

Yes,
The replacement of the security system harness with one with better shielding did solve the problem. Once the harness was changed, it didn't do it again. I have driven for 5 years since it's been changed. By the way, I otherwise love the car. It has been VERY reliable.

[msimmons24]

Thanks for the quick reply.
The Toyota dealership doesn't even seem to know what this part is. They want to change out the ECU at the cost of $1500! Can you tell me where you obtained the part and approximately how much it cost? I see that the Toyota Rav4 in both 1998 and 1999 were recalled for the security system harness. Funny that the dealership doesn't know what I'm talking about.
Any additional information is greatly appreciated.

[GoBuckeyes]

We have a similar problem with the doors locking by themselves on a 2000 Sienna. We noticed the locks clicking closed on a trip in 2003, but it went away.

This past week, the car started locking itself when the key is pulled out of the ignition. When we try to unlock the doors, the alarm sounds! Needless to say, the Sienna is NOT very popular with our neighbors .

We will mention the security harness fix to the Dealer and see what they say. Is there a simple fix we could try, maybe some foil and duck tape around the harness? What is the cost of the harness replacement?

Thanks for the input, this really helped us identify the problem and keep our sanity.