Car sometimes unlocks remote then remote wont work and cant unlock the car manually as it sets the alarm off and immobilizes the car

Check fuses, remote control battery, try to push "unlock" button 5 or more times. If it won´t help, you need Tech-2 diagnostics.

Subaru Keyless Entry Security Alarm Immobilizer Key Remote Start Systems...

start with this link its explains how the security system works

you can remove the central locking fuse , this will stop the lock/unlock constantly , the problem is usually with the drivers door lock mechanism , that is perhaps why you cant lock/unlock with the key, lock from inside vehicle and get out passenger side, that lock should work with the key until you get the lock changed on drivers door

Programming
When
Remote control added or replaced. System malfunction.
How
Obtain all remote controls. A maximum of 3 remote controls can be programmed. Switch ignition ON. Repeat procedure below 3 times: Within 4 seconds: Press lock or unlock button. Within 4 seconds: Switch ignition OFF. Within 4 seconds: Switch ignition ON. Within 4 seconds: Press lock or unlock button. System should now lock or unlock vehicle. Within 4 seconds: Press lock or unlock button. Within 10 seconds: Press lock or unlock button of first remote control. System should now lock or unlock vehicle. Press lock or unlock button of second remote control. System should now lock or unlock vehicle. Press lock or unlock button of third remote control. System should now lock or unlock vehicle. Switch ignition OFF. Remove key. Check operation of all programmed remote controls.
IMMOBILIZER CAN ONLY BE SET BY DIAGNOSTIC EQUIPMENT

sounds like the remote has got a dead battery

the gas flap is operated with the central locking,stand at rear of car with tailgate open,just inside to the right,under the floormat you will find the central locking pump.but first renew the batteries in the remotes then unlock the car with the key and hold the key over for 30 secs, the windows may go down,
then lock the car with the key and hold over for 30 secs,the windows may go up and the sunroof,if fitted will close,then unlock with remote button held down for 30 secs,this will reset alarm/central locking.
if you need to get to gas flap, pull carpet away in boot behind flap area and pull wire to unlock....

Try unlocking locking and unlocking your doors.Then try starting.Works sometimes to override the alarm.Otherwise contact dealership

IF YOU TYPE 1999 RENAULT LAGUNA REPROGRAMME KEY INTO A GOOGLE SEARCH, YOU WILL BE ABLE TO PRINTOFF INSTRUCTIONS TO REPROGRAMME THE KEY TO THE KEY READER.THE IGNITION NEEDS TO BE OFF TO DO THIS

you need the remote control of the alarm to turn the alarm off.

you may need to change the battery of the remote in case it would no longer control the alarm or if you have a valet switch to turn off the alarm, then use it.

the immobilizer is working that is why you can not start the car.

tnx 4 using fixya,

drcool

with any BMW they have their problems, one is the central locking/immobilizer, the central locking is linked into the immobilizer and vice versa, the immobilizer takes it signal to disarm from the central locking and the ignition key ring. (chip in the key) if one of these starts to play up it has loads of consequences this being one of them. they all need to work together for the system to work properly. you would need to read the alarm and immobiliser codes using an ob2 tool that can detect them, and find the fault some problems it can be the drivers door sensor in the lock this is the main door as its drivers side and it controls all other doors on the central locking. if the switch is worn in any of it movements the system will not know the door has been opened, this does not work on the interior light as that is a switch in the door frame. the door lock is lock unlock and deadlock with key with remote fob its also arm disarm alarm and immobiliser. i have seen in some models there is a sensor auto lock so when you walk away with the key the doors lock automatically all lease parts work together. any one having a problem can cause no signal to be sent to the others in the system to start engine .