Immobilizer problem

[Cbates]

Hey guys, went away for the weekend, left my car at home all working fine.
Come back and try and start this car this morning and the immobilizer wont disengage. tried both keys and tested all batteries (all working fine)
Anyone got any ideas of where to go from here? its a 98 gu 4.5L
Cheers

[threedogs]

Once again Yendor would be your man.

[Yendor]

Why do you think it's a NATs problem?

What happens when you try to start the vehicle?

Does the security light go off when the ignition is turned on?

Does the vehicle crank?

If the security light keeps flashing when cranking try disconnecting the batteries for a couple of hours.

Is the vehicle an automatic?

If it is an automatic and the security light stops flashing but the vehicle doesn't crank. Turn the ignition on and check if the reverse light works.

[Cbates]

Hey mate, vehicle doesn't crank, light still flashes when got the car turned to on. It's a manual. So disconnect the battery for a few hours?
Thanks for your help

[Cbates]

Sorry security light turns off when car ignition is turned to on, but immobiliser light stays on

[Yendor]

The security light is the NATs light in the top of the dash.

What is the immobilizer light you are referring to? Does the vehicle have an aftermarket alarm fitted?

[Cbates]

I've never heard the alarm go off however when I lock the car this light starts to flash when I unlock it with the remote it turns off and the immobilizer must turn off. 25205

[Yendor]

Sorry for the delayed response, I've lost my land base internet due to the current weather in QLD and my mobile phone is so slow at the moment.

So the genuine light on top of the dash stops flashing but the one in your photo keeps flashing.

I guessing that you have aftermarket remotes? Do they still unlock the doors?

Is there a siren mounted in the engine bay? do you have any keys to override this system?

[Cbates]

yea aftermarket remotes. They dont unlock the doors at the moment no. so all i can do is open the door with the key.
not aware of any keys to override the system. would my normal key do that or is there a special key?

[Cbates]

Sorry for the delayed response, I've lost my land base internet due to the current weather in QLD and my mobile phone is so slow at the moment.

So the genuine light on top of the dash stops flashing but the one in your photo keeps flashing.

I guessing that you have aftermarket remotes? Do they still unlock the doors?

Is there a siren mounted in the engine bay? do you have any keys to override this system?

all good! thanks heaps for helping me out!

[Cbates]

No Siren in the engine bay

[Cbates]

I unplugged the box and the car started but no central locking or anything still

[Yendor]

No worries mate.

Cheers Rodney

edit

Sorry still have internet problems.

The keyless entry won't work with the box unplugged, what else is not working?

[Cbates]

Yea I didn't think it would, the immobilizer ain't working either. So must be something with that box, at least I have a driveable car!

[Yendor]

To be honest, I'm surprised that you only had to unplug the immobilizer and the vehicle started.

If it was me, I would be removing the aftermarket immobilizer, the genuine system is by far superior anyway.

Then install an aftermarket keyless entry system only, at least when this fails you will still be able to start the vehicle.

Good job on locating the problem.

Cheers Rodney

[Cbates]

Thanks mate! Really appreciate all your help and the effort to try to figure it out! Hope everything up north is going alright for you! Hopefully I can return the favor somewhere down the track