Motronic 4.4 immobilizer

radek93 · Post by **radek93** » 05 Mar 2020, 13:47

I have S70 2.5t 98r. How works immobilizer? Immobilizer module take signal from key and send info to engine ecu? Can I change engine ecu without immobilizer cut?

Post by **misha** » 05 Mar 2020, 13:59

Up to '99 immobiliser reads the code from the key and just sends OK signal to ecu.

Basically....key communicates ONLY with immo2 box and then immo2 box sends OK signal to ecu.
Key(chip in it) is only married to immo2 box module.

That said...up to '99 you can swap ecu since it's not married to the car.
BUT....you will need ecu with the same BOSCH numbers because of software difference with M4.4 management.

Late 850 like mine also have M4.4 from the factory,but it's non-turbo.
You will need ecu from LPT 850 with M4.4 or from '97 & '98 s,v70 for LPT engine.

radek93 · Post by **radek93** » 05 Mar 2020, 14:03

misha wrote: 05 Mar 2020, 13:59 Up to '99 immobiliser reads the code from the key and just sends OK signal to ecu.

Basically....key communicates ONLY with immo2 box and then immo2 box sends OK signal to ecu.

That said...up to '99 you can swap ecu since it's not married to the car.
BUT....you will need ecu with the same BOSCH numbers because of software difference with M4.4 management.

Late 850 like mine also have M4.4 from the factory,but it's non-turbo.
You will need ecu from LPT 850 with M4.4 or from '97 & '98 s,v70 for LPT engine.

Approx. So all I have to do is buy a computer with b5254t and it should work?

Post by **misha** » 05 Mar 2020, 14:06

Yes...but Bosch numbers from original ecu needs to be exactly the same on a replacement ecu...year too.

Post by **misha** » 05 Mar 2020, 14:09

Where are you from?
1997 850 GLT B5254T and s,v70 2.5T(B5254T) from '97 & '98 have the same engine and management(M4.4).
So...ecu swap between those two cars for EU spec.will be plug and play as long as Bosch numbers match.

radek93 · Post by **radek93** » 05 Mar 2020, 17:54

misha wrote: 05 Mar 2020, 14:09 Where are you from?
1997 850 GLT B5254T and s,v70 2.5T(B5254T) from '97 & '98 have the same engine and management(M4.4).
So...ecu swap between those two cars for EU spec.will be plug and play as long as Bosch numbers match.

Poland. Ok. Thank You.

Post by **RickHaleParker** » 05 Mar 2020, 22:10

radek93 wrote: 05 Mar 2020, 14:03 Approx. So all I have to do is buy a computer with b5254t and it should work?

Look at your ECM. You will find a software number in the format "0 261 204 XXX".
You need to find a replacement ECM with the same software number. All ten digits must match.

Post by **misha** » 06 Mar 2020, 02:16

RickHaleParker wrote: 05 Mar 2020, 22:10 Look at your ECM. You will find a software number in the format "0 261 204 XXX".

That would be a Bosch part number(10-digit number).
Software numbers are under bar codes.

Post by **RickHaleParker** » 06 Mar 2020, 13:39

misha wrote: 06 Mar 2020, 02:16
RickHaleParker wrote: 05 Mar 2020, 22:10 Look at your ECM. You will find a software number in the format "0 261 204 XXX".
That would be a Bosch part number(10-digit number).
Software numbers are under bar codes.

All Bosch M4.4 hardware is the same. The only difference between one Bosch M4.4 part number and another is the software. That is why the tuners call out the software version by the last three digits of the part number. Match the numbers as I outlined above and the software will match. It is that simple.

Post by **misha** » 06 Mar 2020, 14:06

Nope.....
https://www.google.com/search?sxsrf=ALe ... ZVxo_UDmQM:

Software version is somewhere under those bar codes.

Bosch 10 digit numbers indicates just part number for ecu.

Those numbers are the same and software numbers(codes) are different.

As you can see from the picture...last 3 digits from Bosch part number (10 digits number)doesn't match with any number under the bar codes.

I have somewhere in my computer a data where exactly is softvare version,but i'm on the phone now.
I'll post it if you want to see yourself.