Hi all,

I'm currently doing a GL upgrade project, which means leaving nothing standard on my 1995 non-turbo AWD impreza .
Centerpiece is of course the engine: an MY04 Forester STI engine.

I have the total wiringloom of the car it was once built into, and i want to use it on my car.
So i can make the drivebywire throttle body and variable valvetiming work properly.

But now i have found out that there is a system called CANbus present in the electrical circuit.

From what i have heard this is a system that checks al parts its hooked up to and detects if there is something missing, a rearlight unit for example.
If so there will be warning lights flashing and the car might not start or something.

I was planning on using only the engine and dashboard wiring of the MY04 loom, but then the CANbus system wil detect there are parts missing.

I know that Ford also uses this system and it can be bypassed welding a 120 Ohm resistor somewere, so the the system is fooled in believing everything is ok.

Can anyone tell me some more details about this system as used by Subaru?
And how to bypass it?

greets

Aram

Sounds like an intresting project. I'm not positive that the 04 Subarus were using CAN or not, I think they are still using what's called K-line (think of it as a 1 wire serial port). I know that Ford and GM are heavy users on CAN bus applications, most of the EDM and JDM models have in the past or are still using K-line. Depending on the way the system is set up you may get a lamp to come on (CEL) or a string of items just won't work. On a typical CAN bus there is supposed to be a termination at the end of a chain, I believe that it's only 50 ohms but I may be mistaken. For some more information you can look at this site regarding CAN bus systems.

www.kvaser.com
-or-
www.autotap.com (also has good info)

Cheers

Chris Z.

I was told it was the CANbus system, but off course i do not know for sure.
Is there a way to know for sure?

My problem is actually this:

I have a 2004 STI engine, this is a bit different to the non turbo MY95 1.8 engine.
2 of the biggest differences are:

1. Variable valve timing
2. Drive by wire throttle system.

I want both systems working on the car.
I can have the vvt working with an aftermarket ECU, Autronic or something, but that will cost me an additional 1800 euro's.
That is money i'd rather not spend of course, but ok, that can be done.
I could also put on the inlet manifold of a MY99 turbo with a mechanical throttle body and electricals but i that would be a last resort.
Also I'm not sure if the ECU will take altering the inlet manifold electronics (canbus might "see" this and throw a fit??).

So my initial thoughts, before i knew canbus existed, were that i could do 2 things:

I could only weld the engine part of the my04 engine loom to the internal part of the my95 loom, which means alot of welding!!

or

I could use the my04 engine and dashboard loom and weld the relativly small loom from the part the goes to the rear onto it.

The latter option meant having all the my04 dash parts also, counterset, knobs etc.
These parts i can get my hands on so that wasnt to much of a problem.

So this was my favorite option because this also meant i could use the my04 pedalset with sensors for the drive by wire system and have that connected to the loom with no probs.

So i was pretty thrilled having this solution and having this big worry pretty much under control.....until mr canbus dropped in.

It was said to me that it would make it impossible to get it working properly defenitly because i don't have the code to get into the ECU and reset things also.

That is why i'm trying to figure out what options i have and if it is possible to fool canbus in thinking everything is attached to the loom, by for example welding resistors to the connectors or something.

So if any of you guys have ideas I would be most gratefull to hear them of course .

I will be looking at those sites now :).

greets

I'm not "Mr. CANbus" :)
I'm just a tech who happens to be in the employment or a company that deals with a lot of calibration and rapid prototype systems which at the moment uses a lot in the way CAN.

Also unless you have a good map of what is actually stored in the memory of the ECU, going in and changing the strategy and calibration files may result in bad things happening. There is not always a way to just turn off a device, it can be done in some instances but not without some knowledge of what is really going on in there.

If I were to do a swap (which is in my future plans) I would try to get every last piece that I could from the donor vehicle and both sets of wiring diagrams before embarking on such a project. This is how we got a full Mustang Cobra powertrain in to a Focus, working A/C and all.

Hi CHris,

That Mr, Canbus wasnt revered to you, i meant that i heard of that canbus system for the first time back then ;).
I have most of the stuff of the donor car, although not all of it.
What i am looking for, and what i asked about on here also are the wiring diagrams of this car.
But it seems that they are not very much available :(.

And, as you said, I'm also trying to figure out how this system actually works on the Subaru's and it seems that there isnt much information around on it, so it is pretty hard to find something ;).

But i'm going to keep asking around for it coz it is a pretty interesting subject.

greetz