Weird keyless entry problem
 

Hello all, I have owned my 99 gs400 for a little over a month and I love it. I have only had one problem which is the starter which I have not replaced yet. Anyway, yesterday I started having a problem with my keyless entry. It has worked fine the whole time I've had the car then all of a sudden it's acting screwy. It began when I got out and tried to lock the car with the fob.....nothing, red light on fob so it's working. Lock, unlock, trunk button do nothing. All actuators work because switch on drivers door still locks and unlocks everything. Checked all fuses, went online to try to figure out how to reprogram fob, found it, still no luck......but while trying to reprogram, realized that if I lock the car from the drivers door first and get out and close the door, everything on the fob works again until I hit the unlock button which at that point will unlock the car, and put down all of the windows and slide the sunroof back, then the fob will not work again until I lock the doors with the switch. Any help is greatly appreciated.

*NOTE*
Also, the problem is happening with both of my master keys, so doesn't seem like the fobs need to be reprogrammed. Seems like something on the cars end.

Could be door actuator motors dying. I used to have to manually lock my drivers door to get the remote to work before I replaced mine...

All actuators seem to be working fine as they all 4 lock and unlock perfectly when I use the lock/unlock switch on the drivers door.

*NOTE*
I noticed this morning when I left for work that the fob to car communication worked perfectly for 2 lock/unlock cycles and then went back to the issue stated above.

I second a actuator. I've had the same problem for quite a while and too must lock the driver door manually for the fob to work and yup, works intermittently. Also, try opening each door and making sure that each door turns the dome lights on, IIRC the actuator is the unit that has the door "open/close" sensor on it.

All doors activate the dome light, how would I determine which actuator in which door is causing my problem?

And why the hell is it making my windows roll down and my sunroof slide back?

I don't think they understand the problem. Its not the actuators because they wouldn't make all of the windows roll down. I'm experiencing the same thing. If the door actuators were failing, when you unlock, you will still hear the other good motors/door locks working or attempting to unlock/lock. What we're experiencing is NO activity is present randomly. For example, I walked to my car and unlocked with the key fob. Arrived to destination and attempted to lock the door. No activity whatsoever. No sounds or anything. It seems as though my key fob didn't work at all. Trunk release button wasn't working either. Key fob light turns on when pressing but thats about it. And sometimes all of the windows including the sunroof will open. This is not a symptom of a bad actuator. A few months ago i replaced my actuators because during that time they were going bad. You would hear the locks attempting to work.

Try changing your fob battery? I know you said the red light illuminates but just saying that it would be an easy possibility to rule out and inexpensive.

Also, any difference if you hold the fob up to your chin and press a button (since the signal gets amplified)?

You're right, if it were an actuator at least you would still hear the lock try to open. And yours work the button inside the vehicle. Sorry I can't help more. Good luck!

bumping this thread. I have to manually lock my driver door. If i use the fob it will unlock all the doors except the rear passenger door. any ideas? The fob will also not lock the doors. The door lock and panic button seem to be smushed in a bit as well.

My malfunction occurred after I disconnected battery for 6 weeks do to my extended trip to Europe.
After return from my trip and reconnected battery, remote control stop working, but I was able to start the car.
I had similar problem, as described in this thread with exception, my remote didn't work at all (no beep, no flashing lights, no lock/unlock etc.) just dead.
Also it acted weir, when I left my windows open and locked car with the key, windows start closing automatically. Previously(correct operation) I had to cycle key twice during locking to get this windows close.
Try to reprogram all keys, still not working all remote functions.
After hours of trying ant trying suddenly it suddenly start working.
I'm not sure what help as I try to do as fallow:
1. Lock drivers door with door switch than open doors, try to use remote, did not work.
2. lock drivers door with door switch, open window, while doors are still locked i used key and inserted to lock, than unlocked door, opened door and try to use remote, it start working.

My feeling is that ECM holding information and processing commands from remote got some how corrupted. By doing this sequence it most likely synchronized or reloaded proper operation sequence.

Another theory of mine is that during all this malfunction i realized that sometime when I unlocked door with key and opened door, car alarm was tripped. By researching this issue I noticed my drivers door lock acted lazy (knob on doors didn't move to unlock position all the way). I try to repeat unlocking with the key several times and after 3 to 5 cycles that knob moved all the way and by opening doors car alarm was not tripped.
Perhaps some switch in my drivers door lock do not work properly (intermittent) and cause this issue with remote.
To be sure i just ordered a new door lock actuator and planning to replace it.

Note:
Lexus car dealership after testing my car recommended replace front Driver Door ECU.
I don't understand why this was suggested as all my door locks and windows in the car works fine from switches in the door.
As all this door lock and windows work in multiplex, there is no way module is defective. I had suspicious on Body ECU1 what most likely holding all programmed remote keys and processing commands from them. I my theory I eliminated malfunction of Wireless Door Lock ECU as I assume this module acting as receiver, perhaps is holding (memorizing) all remotes, but most likely is not processing all sequences of locking/unlocking, panic, open windows etc.
But this is just my speculation as I was not able to find on the web what module is processing all commands from key-less (remote) entry.

I hope so this will help other Lexus owners.