Just bought a 95 lexus LS400. Used the key to lock the doors. Then when i unlock it, the alarm goes off and the car won't start. What do I need to do to start the car again.

It is telling me to lock the doors with the key, this will arm the system, then you should be able to unlock the doors after about 3 seconds and this should disarm the system. Also, if it doesn''t try unlocking the passenger side door or the back glass with the key. Let me know you must wait at least 3 seconds before unlocking back glass or passenger door to disarm system once one door is unlocked without setting off alarm it is disabled. hope this helps

Depending what part of the country this car was purchased originally, the alarm system can be different. These are after market systems installed by the distributor or dealership. Different systems are connected differently. Either way the alarm system is connected to the engine controller and or the main electrical circuit. This has to be removed and the circuit reconnected. I would advise taking to a car alarm specialist and have them replace or remove it.

I think that's the alarm system as well.the most important thing is the alarm system is still working?step out yr car try to use remote key to lock n unlocked,if that's working.i don't worry at all.lock n unlock are alarm system reset itself.should be normal,battery is super low or dead .good luck for u

if it has an alarm hook up the cables so the alarm goes off then deactivate it with the remote. if you dont have the remote then you need to take it to an alarm shop and get a remote programmed for it if they cant they will have to remove the alarm and you will need to get an aftermarket alarm for it but yea it wont start because the alarm was on. when you try to jump a car with an alarm even if you have the keys in the ignition the alarm will go off its a fail safe so noone can jump your car to hotwire it. but just do as i said jump it and disactivate the alarm with remote and it should turn over with ignition......
one thing you can try close all the doors lock the doors.....USE YOUR KEY TO LOCK THE DRIVERS SIDE DOOR AND THEN UNLOCK IT. See if this might reset it.....
Best of luck i hope this will help

yer right,,,its a dam lexus??? there nothing but problems when they go wrong,,, not that they go wrong often, but when they do??????
i realy cant think of a way you could do what you wont to do,,,,, but i can think of a way to put it right, take it into the lexus dealer they will fix the alarm for you,,,only one thing that springs to mind is when did you last change the kye fob batterys?????
however when you do change them do it very very fast,, or you lose the coad for the alarm???
then it wont go at all,,, its a lexus!!! yuck!

sounds like an engine immobilizer problem. close all doors,hood & trunk completely. lock and unlock the car three times with remote, then put key in door lock and lock & unlock three times.
did you accidently try to start with wrong key?

1. sitting in driver seat, with driver's door OPEN, press lock/unlock button ON THE DRIVERS DOOR to lock all doors, then manually unlock driver door only.
2. Insert YOUR key in ignition, DO NOT TURN, then remove key.
3. Using the same lock/unlock button ON THE DRIVERS DOOR, slowly press lock-unlock in 5 cycles
4. Shut door.
5. Open door.
6. Using the same lock/unlock button ON THE DRIVERS DOOR, again slowly press lock-unlock in 5 cycles
7. With the door open insert your key into the ignition, turn to 'on' position (DON'T START), wait 5 seconds. Turn off and remove key.
8. Locks should cycle once (Car will lock and then unlock once by herself). If they don't cycle or they cycle more than once, do steps 1-7 over.
9. Now using the remote, push lock button, hold for one second, then release the button. The locks should cycle once. If not, start over and go slower.
10. Close the door.
11. Open the door.
12. Press the lock button on the remote. The locks should do a lock-unlock cycle.
13. Close the door
14. Press the lock button on the remote, the doors should lock.
15. Press unlock button and the doors should unlock.

Long beep to follow if successful.

Remote Programming Instructions

1. Driver's door OPEN and unlocked, all other doors closed and locked.

2. Insert YOUR key in ignition, DO NOT TURN, remove key.

3. Using the MANUAL lock/unlock button ON THE DRIVERS DOOR, slowly press lock and unlock 5 times (count the lock 5 times and unlock 5 times).

4. Shut door.

5. Open door.

6. Using the lock/unlock button ON THE DRIVERS DOOR, slowly press lock and unlock 5 times (count the lock 5 times and unlock 5 times).

7. With the door open insert your key into the ignition, turn to on position (DON'T START), wait 5 seconds. Turn off and remove key.

8. Locks should cycle once (Car will lock and then unlock once). If they don't cycle or they cycle more than once, do steps 1-7 over.

9. Now using the remote, push lock button, hold for one second,
release. The locks should cycle once. If not, start over and go slower.

10. Close the door. Open the door. Press the lock button on the remote. The locks should cycle. Close the door. Press the lock button on the remote, the doors should lock. Press again and the doors should unlock.

put key in door any unlock manually twice, this will de -activate alarm

My 1991 Lexus LS 400 does something similar. When the alarm goes off I use the key to unlock the passenger side front door and it turns the alarm off. Go figure, I know it sounds funny but it solves the problem for me.