Immobiliser? Starts without transponder chip

[sparkyjohnmarky]

Hi,

This is my first listing so be gentle with me

I have a 94 ecotec 16v. In theory this vehicle souldn't have an immobiliser, but it does. I tried to buy new keys for it, but have found out that the key I have, does not have a transponder chip, but the car still starts. So the immobiliser has been bypassed somehow, has anyone come accross this before?

I have checked all the wiring for power and continuity, which is o.k., but I have not checked to see if the wire from the transducer, terminates at the ECU. I have also checked the codes in the ecu memory, but it does not return a code for an immobiliser fault.

I have looked in my haynes manual for the location of the immobiliser relay, a photo of the anti-theft system, shows the relay just above the glove box, but there's nothing there .

Does anyone know the location and wire colours of this relay?

Regards

[tazz666]

or some one has had the immobaliser switched off by tech one , as i had the v6 immobaliser switched off in mine as, as i have an aftermarket immobaliser fitted for insurance purpose

[Robs-se]

Thought the immobaliser was part of the locking system, my SE wouldn't start if the doors were locked and that was the standard factory alarm

[BIG DAN]

i have a 1990 with an emobiliser but all it does is not start unless the drivers door is unlocked 1st but it is all standard

[sparkyjohnmarky]

There is definitely an immobiliser, and from the replys received, it appears the immobiliser has been switched off, as tazz666 has suggested. I have not found a chip, on the Immobiliser control unit, the black plastic ring around the ignition lock. I am in the process of buying an opel scanner, which may be able to tell me if the ecu has been programmed not to look for the for the transponder code.

Correct me if I am wrong, but according to the haynes wiring diagrams the alarm and immobiliser are not connected, but are together make up the anti-theft system. The immobiliser control unit is shown as having seven wires: term 30, term15, signal from ecu, signal from speed sensor, signal to ecu, signal to diagnostic plug and term 31. There is also supposed to be a relay that is somehow connected to the crank wire, and only closes when the correct signal from the ecu is received, but the wiring diagrams do not show this relay, even though it appears on the overview of the anti-theft system.

I have found a number of errors in the haynes manual and now wonder if they have got this wrong as well.

As mentioned I am in the process of buying an Opel scanner and will probably wait to sort this problem out when I've got it.

Thanks for the help

Regards

[Robs-se]

It is also in the Owners Manual as well