Immoblizer

The coils should not be the cause for the keys not being recognised by the immobilizer or security system.

The keys not locking the doors means the door switch could be bad and unlocking the key does dot disarm the security system.

Did the alarm go off by itself or while you were attempting to open the door or start the vehicle?

Have yu tried to lock and unlock the door with the key?

Try using the passenger door or trunk lid.

The driver door lock switch could be bad and does not unlock the door. Under such circumstances when you open the window to unlock, it is deemed forced entry and this would trigger the alarm/security system.

When the alarm system is breached, it can trigger the immobilizer and prevent starting even though you have the master key. You need to disalrm the security system to enable the immobilizer to work.

Since the problem is preventing starting, the key transponder might not be very reliable and reprogramming the key might solve the problem. Toyota and Lexus are supposed to be similar but then again where experience is concerned, I would rather go to the Lexus dealer.

Yes, since the key is intermittently not being recognised by the immobilizer, reprogramming the keys should be the first thing to do as both sets of keys have the same problem.

Prior to reprogeaming the keys, recheck the wiring and power supply to the immobiulizer ans security system. Any disruption can cause the problem as well. One thing that you need to look at would be the door locking system. If the keys do not work on all dors, you definitely have a fault with the power supply or security system. If it is only specific doors, then the problem would be the door switch.

Thank you for the offer of a donation but sorry to say I am not able to explain it to you as the system upgrade to our site is extensive and I seem to have lost track of quite a lot of things. Anyway I have contacted our admin and someone else would be answer to you shortly.

Keep me updated of how it goes.

Hi KISHA8223,
You can donate by asking another question and choosing to donate at that time. You can just thank the technician that helped you instead of asking another question unless you have another one. We will have another donation option button up soon to remedy this work around. Have a great day.