Saab 900NG immobilizer madness

**duckduckduck** · 1st June, 2023, 07:58 PM

Hi guys,
A few weeks back I bought myself a 1997 Saab 900NG coupe, this is suposed to become my daily car.
When I bought it, the car had no fuel pressure, I had to disassemble the fuel pump to realize that a piece of tubing became too dilated and came off.
I changed this piece of tubing and I now had fuel pressure, but the car still refused to start.
At that point I thought it had something to do with the fuel injectors, thus I removed the inrector rail from the engine and was surprised to see that the car was cranking but only fred the injectors once then nothing, I thought it was the Crank Position Sensor but a friend of mine told me that this could be an immobilizer issue.
This is where I began my journey...

After a lot of reading on multiple forums I stumbled upon a guy who explained that if the fob batteries were not working then the car would not start.
I changed my keys, followed his "lock unlock" procedure with the fob, and to my surprise, the car started.

It started multiple times tince then, until today when it didnt.
I spent the whole afternoon trying to start my car, changing the battery multiple times over, in the car, in the fob. NOTHING :/

I have fuel pressure at injectors and they do not fire, same as before.
The car does not recognize my key anymore, I can tell that because the alarm goes off when I open the door with the key but it does not stop when I put my key in the ignition.
The fob seems to work properly as it unlocks/locks the car and unlocks the trunk.

I looked for a way to bypass the immobilizer but to no avail, all I could find is for other version of the car, the pin shorting method would not work for me because after looking at the diagram it would not make sense and I could fry my ECU ?
I have attached the schematic I have purchased for my car (this is also a way of making it available to anyone who does not want to pay for it

), the color code is the right one.
My alarm/immobilizer module is the 45 88 877 with the black connector, not the yellow one, yellow is for 47 10 448 if I understood correctly.

This was the first problem I wanted to ask, but since I am an idiot I decided that I would provide a dump of the eeprom (non rotated 93LC46) of this module.
Why am I an idiot ?
Because while my wiring is correct, and the supply voltage too, I was in write mode and I think I my accidentally have overwritten some of the bytes with garbage.
Anyways, if anyone can provide me with a clean dump for this eeprom, or confirm if the one I have is good or not.
And if anyone has a solution for disabling immobilizer on my car I would greatly appreciate your help.

Anyways, thank you for taking the time to read this post.