Immobilizer
Thread Starter
Rennlist Member
Joined: Aug 2006
Posts: 2,526
Likes: 82
From: Finland
Immobilizer
I posted earlier that I know how to trick the immobilizer on a 1996 993.
It is not correct and here's why I first claimed so.
While installing the Motec in my 993, we noticed that the anti drive off/immobilizer is not getting the correct signal from the ECU (since the ECU is not there) and therefore there is no voltage to operate the starter relay.
With the wiring diagrams at hand, it was quite easy to find a way around it. The control voltage for the starter circuit relay passes trough the anti drive off device so just supply +12V directly to the starter circuit relay, and wola! The car will start!
Well, that is only one of the two things the immobilizer does. What it also does is it sends a signal back to the ECU which without the ECU will not "work".
In my case it is not relevant since there is no such requirement for a signal on the Motec. But, if you have the original ECU, it will not be enough just to get the starter circuit, you also need that signal so the ECU starts working as well.
After my post today in Kilodawgs thread, several people have asked me to send the info on how to trick the immobilizer. Before I sent what I knew, I did a little search on the forum and found this very informative post: https://rennlist.com/forums/1769961-post5.html
Immeadiately after reading it, I remembered that I had wondered why I still need to press the button on the key chain to get the car started, even when I have tricked the anti drive off device. Now I know...
According to the wiring diagrams, there are two "data" lines going into the anti drive of device, one must be for the signal from the alarm and the other is the line going into the ECU. I'll bet you my friend (who holds a masters degree in electrical engineering) can reverse engineer the thing and find away around it...
Stay tuned!
It is not correct and here's why I first claimed so.
While installing the Motec in my 993, we noticed that the anti drive off/immobilizer is not getting the correct signal from the ECU (since the ECU is not there) and therefore there is no voltage to operate the starter relay.
With the wiring diagrams at hand, it was quite easy to find a way around it. The control voltage for the starter circuit relay passes trough the anti drive off device so just supply +12V directly to the starter circuit relay, and wola! The car will start!
Well, that is only one of the two things the immobilizer does. What it also does is it sends a signal back to the ECU which without the ECU will not "work".
In my case it is not relevant since there is no such requirement for a signal on the Motec. But, if you have the original ECU, it will not be enough just to get the starter circuit, you also need that signal so the ECU starts working as well.
After my post today in Kilodawgs thread, several people have asked me to send the info on how to trick the immobilizer. Before I sent what I knew, I did a little search on the forum and found this very informative post: https://rennlist.com/forums/1769961-post5.html
Immeadiately after reading it, I remembered that I had wondered why I still need to press the button on the key chain to get the car started, even when I have tricked the anti drive off device. Now I know...
According to the wiring diagrams, there are two "data" lines going into the anti drive of device, one must be for the signal from the alarm and the other is the line going into the ECU. I'll bet you my friend (who holds a masters degree in electrical engineering) can reverse engineer the thing and find away around it...
Stay tuned!
Thread Starter
Rennlist Member
Joined: Aug 2006
Posts: 2,526
Likes: 82
From: Finland
Here's how to semi-permanently by-pass the immobilizer IF you have an aftermarket ECU or your ECU is programmed so that it doesn't need the signal from the immobilzer.
Semi-permanent fix:
Semi-permanent fix:
Addict
Rennlist Member
Rennlist Member
Joined: May 2001
Posts: 12,808
Likes: 782
installed
then the only thing you need is a non OBD2 chip fpor a 55pin ssetup or reprogrammed '97/98 DME
