1993 SC400 lock and anti-theft Engine won't Start
 

Hello guys.
When i left my 1993 LEXUS SC400 i closed the doors with the Key Remote but after i came to my car then the Remote didnt work! So i opened the driver's side door with the master key. Then the Alarm started and i tried to open the driver side door by key but anytime i turn the key to the unlock but the door locks it by him self! Maybe security!? So i have to hold the key to the unlock side and then i can open the door! I Went around to the passenger door and had trouble unlocking on that side as well and the Alarm doesnt get off!
I jumped in the car and put the key in the ignition, turned it and the alarm went off but the car won't start. The car thinks I'm trying to steal it!! The trunk won't open, the manual lock buttons won't operate and I can't start the car.
My locks work by using key! I can lock and unlock the doors but only if the Alarm is on then i cant turn the key to unlock! It turns to lock by him self! I think its just the security!
im from Germany and my SC400 is very rare and Lexus Germany cant help me :-(
My only hope is you guys. I saw an Thread a guy had the same problem here 10 years ago with his 1990 LS400 but he didnt write what was the main problem!
Please help me guys.
Thank you

Replace batteries in the remote. When the alarm is triggered, press lock or unlock and it should deactivate.

I already tried!
I changed the Batterie but didnt work!

Is it possible to reprogram the 1993 SC400 key?

German dude,


Have you tried inserting the key into the driver-side lock and turning if left to activate the alarm? Then remove the key, re-insert it, and unlock the door by turning to the right. That's how it works on my '95. Is your alarm a third-party add-on or the Toyota/Lexus factory alarm? I thought the factory remote alarm key wasn't available until 1996 but I could be wrong.




.

My Alarm is Original From Toyota/Lexus and i tried all the things what you said but it doesnt work!
How can i disable the Alarm!?
I dont need it! I just have trouble now

German dude,


I would disconnect the battery and wait half an hour. Reconnect the battery and try locking the car manually with the master key. Then try unlocking.



It's worth a try...

I already tried this!
Anytime i reconnect the battery then the Alarm starts again and the only way to turn it off is to try to start the engine but it doesnt work :-(

might be a failing ecu.

I think so too!
Because i tried everything!!
I ordered new ECU from ebay!
I can change it? Or i habe to reprogram it?
I thought maybe something wrong with the Lock? Door locks or trunk lock? What do you think?

Disconnect the alarm module connector and see if that helps. It is behind the rear passenger quarter panel or pull the fuse for the security system. It is worth a try if you haven't already tried that.

Alright! I will try it!
Where is the fuse?

My Central lock doesnt work!
I think thats the reason why the car wont start!
The Alarm deactivate only if the central lock opens, is that correct?

I would also love to know what fuse this would be! :)

The key lock switch is the problem. I just took one apart and cleaned it and have not tried it yet.