immobiliser - how it works?!

[arimendiii]

does anyone know how does the immobiliser works. I have a 2002 1.8T, and when i activate the immobiliser (closing myself inside the car) the car starts without problem. is it supposed to block the engine when the immobiliser is activated???

[zollaf]

welcome. the immobiliser consists of a chip in the key that is read by a coil in the ignition switch. use the wrong key and it wont start. locking the car activates the alarm.

[arimendiii]

thanks for replying, but what i wanted to know is, what's actual role of immobiliser, is it a sort of alarm, because when you lock the car, and then put the key in ignition, the engine starts normaly, whereas car alarm blocks the engine from starting

[blackpool1974]

My take on the immobiliser is:

1. If somebody breaks into your car without your keys, they are not going to be able to start the engine

2. If somebody makes a copy of your key and can get into your car, they are not going to be able to start the engine either, unless they paid £160 top get it coded !!

the key fob has a coded chip. When the key is inserted if the code matches the ECU it will allow the car to start, if it doesn't it will try but never actually start

The alarm just makes a noise, some people have been driving and the alarm goes off so it cant be anything to do with the immobiliser

[JohnyIre]

My take on the immobiliser is:

1. If somebody breaks into your car without your keys, they are not going to be able to start the engine

2. If somebody makes a copy of your key and can get into your car, they are not going to be able to start the engine either, unless they paid £160 top get it coded !!

the key fob has a coded chip. When the key is inserted if the code matches the ECU it will allow the car to start, if it doesn't it will try but never actually start

The alarm just makes a noise, some people have been driving and the alarm goes off so it cant be anything to do with the immobiliser

Sounds correct to me. If you put foil over your key it can stop the car picking up the chip signal, and the car won't start.

[arimendiii]

Ok, so that's why the car starts, because eventhough the imobiliser is activated it still recognises the key and the engine starts. which is a bit different from car alarms, which when activated it still "doesn't care" that the proper key is inserted, and they will stop the engine from starting and starts beeping.
anyway thanks a lot, because I was really worried and was thinking of instaling a new alarm on my car.