disable alarm
 

92 300SC.
Alarms when driver door opened with key. Remote not working.
Will not start now.
How can alarm be disabled?

I haven't read of anyone figuring out how to disable the factory alarm, but the alarm going off when opening the drivers door is a somewhat common problem:

https://www.clublexus.com/forums/lex...e-doesn-t.html

As I recall, if you put the key in the ignition when the alarm is going off, that triggers the kill switch and you can't start it. Pretty dumb safety net, if you ask me. Disconnect the battery and reconnect it to reset the system.

I had the same Problem Similar with my Rx330 2006
 

Hello people who are having this problem to or you might be having this problem. I had a bad battery for a long time I just got a new one a couple months ago. When I had this problem occur I finally figured out you have to put the key in the ignition and turn it and the car alarm will not go off.
I hope that works for you

blessings

If you do that with a SC300/400, you activate the kill switch. I made that mistake the day I bought my first SC... I guess Lexus thought it's easier to hotwire an ignition than it is to jimmy a door lock?

This happened to my 95 sc300 car wouldn't start after I put key in ignition and alarm stopped. Used key to lock and unlock PASSENGER door three times I think this resets alarm car started fine.

Both doors work the same in the sense that unlocking them shuts off the alarm if it's sounding, or prevents it from sounding in the first place. The problem arises when the lock sensors stop picking up that the key has turned the cylinder. That's more likely to happen on the driver's door because of how much more it gets used, so the passenger door becomes the lifeline until you replace the bad sensor.

It's Lexus' intent that putting the key in the ignition to silence the alarm activates the immobilizer. Why, I have no idea. Common sense would tell you the door sensor was dysfunctional and the presence of a key in the ignition should be proof enough that it wasn't a break-in... Maybe they thought hot wiring is easier than picking a lock? At any rate, I hadn't heard that locking & unlocking one of the doors three times resets that. I thought the only option at that point is to disconnect the battery. I wish I knew that on Day 1 of owning my first SC, when I was stuck in the bank parking lot with a blaring alarm and no tools on hand to try the battery reset...

Whoa, I didn't scroll up when replying a few days ago. At least I was consistent in my responses 3 months apart!

Thanks for the help everyone. This thread was helpful. I lost the button to my key when screw came off and it hasn't work. By any chance do any of you know where I can find part for the button on side of my 92 SC300 key?