I've read though loads of threads on here about Prodrive ecu's for the 1997-1998 Classic Impreza 2000 UK

Most people say you need them recoded to your keys and as they have an immobilizer fitted inside as opposed to the 1999-2000 which has a separate immobilizer fitted.

I decided to help other owners and sort this out once and for all. I bought a Prodrive ecu fitted it and it worked fine.

I wondered if this was the same with all Prodrive ecu's so i borrowed another and that didn't work, engine light came on. So i fitted my orignal 8S ecu and now that will not work either the engine light has come on.

So i fitted the other Prodrive ecu i bought and that works fine

So instead of answering any questions i've opened up a whole mine field

 

So does this mean you have a spare prodrive ECU that could be sold to someone in need? Lol

 

I'm under the impression that there is a separate immobiliser ECU in 97-98 cars that is paired to the keys and the ECU. If either keys or ECU changes, it needs to be reprogrammed.

When I changed from my 8S 3-plug ECU to the Prodrive SP ECU (A18-000 DV8) it wouldn't work until I got my local Subaru dealership to recode 'something' in the car. The engine would start but then immediately it cut out with a dash light flashing. After the dealer recoded whichever bit it is, it would then run fine.

After having this done, as a bit of an experiment, I tried putting my old 8S ECU back in. The car wouldn't start and behaved exactly the same as the PPP ECU had originally done before being coded. This I what makes me think there must be something else that actually gets paired to both the keys and ECU.

I can't explain how you've got an ECU that doesn't seem to care about the immobiliser ECU though! The only way i'm aware of getting round this is that it can be disabled is via an ESL. Might be worth opening it up to check what's inside! ;-)

 

Thanks Ben thats some good info.

Yes i think your right, think the immobiliser is separate, but must be coded into the ecu and keys.

I thought the same as you, plugged it in, then thought, it must have ESL, opened up both SP ecu's, and look the same, no ESL. Gutted

I can't quite understand how my 8S no longer works with my car, but one of the SP ecu's works fine. It makes no sense.

Has the ECU some how paired itself up with the keys and immobiliser or has the function been disabled like ESL?

 

I was hoping Andy would come on and shed some light on this, but doesn't seem he wants to. Any one else know whats happening?

 

Why don't you read the fault codes that come up when you fit the ecu that doesn't work, that might give a clue ?

cheers

bob

 

Thats an idea Bob, i don't have a fault code reader though. Worth getting one i guess

Just thought i'd ask, thought maybe someone on here knew like You or Andy might know, very weird and confusing.

I've managed to workout that the imobliser is separate from the ecu, but still ecu is some how tired into imobliser. Just like to get things clear in my head.

 

u dont need a code reader on classics... use the black diagnostic connetors under the dash.

 

?

 

The wires you connect to read fault codes via the flashing engine check light.

I have tried multiple ECU's in a MY00 and found the following:

The chip in the key is coded to the transponder. This transponder is a little black box on the underside of the steering column. It is wired to a sensor on the ignition barrel and into the loom. As long as the key matches the transponder I could swap any ECU back and forth. Or swap any key chip and transponder as long as they stay paired.

I did however have one ECU that would not work at all. Even with its original key chip and transponder. I assumed this ECU was damaged as when the immobilisor takes effect it allows the car to start then cuts the power after a few seconds. This faulty ECU wouldn't let the car start at all.

I am going to test to see how the transponder cuts the power at some point. It appears to be wired into the fuel pump so if it just cuts fuel pump power after a few seconds I can easily wire around it and take it out of play. Of course this would disable a security feature... But I am making a track car and have already ripped out the Sigma system and rewired all the parts that took control of.

 

http://www.jollygreenmonster.com/help.htm This shows how to check the fault codes using the diagnostic connectors.

 

Yours is a 2000 model which has a different ecu, when you change ecu's on a v3 or v4 you have to get the ecu recoded by Subaru, i'm guessing that its linked into the security

I did wonder if I reset the ecu and then fit another ecu in, would this then recode the old ecu back in?