Central locking problem.

I would go through the fob reprogramming sequence to lock/unlock the car. I just did this last week for my 2002 with a remote fob I've had sitting for a couple of years. I put in a new battery, reprogrammed and it works like a charm. I followed the steps located here:

Coastal Electronic Technologies, Inc. Reprogram sequence

It's not impossible the fob is bad. I had two proximity remotes for my 2005 Prius that do not work. One doesn't open/lock doors but will start the car. The other will open/lock the doors but won't start the car. Now, $150 later with a new dealer supplied remote... I have a fob that does everything. No amount of programming would budge those two older remotes, including programming with a Toyota Handheld scanner... So, in short, be prepared to buy another remote. They're available on Ebay.

 

If the car is already responding to the fob in some form (such as unlocking the doors), the programming has already been done.

If you hear sounds from the car when you tell it to lock, but it then is not locked, probably one of the lock actuators is weak, and is not able to move its door fully to the locked state. The car detects that, and responds by fully unlocking again. You may be able to see this by looking through the windows to watch the door lock knobs while trying to lock with the fob.

Why the car's reaction to an incomplete lock is to fully unlock, is anybody's guess, but I guess they figure that way you will notice the problem and wonder how to fix it. The answer is to find which door's actuator is weak, and replace the actuator. There are other threads on that.

-Chap

 

A weak 12V battery could be involved too. It would be worth while to measure it with the car off for an hour our so.

Bob Wilson

 

That is why we measure the voltage when the car has been off for an hour or so. Measurement removes all doubt.

Bob Wilson