2002 WRX wiring = 2003 WRX wiring?
 

So not only do I not have a MY2003 specific FSM in my cache of that sort of stuff, all the places I look online can't seem to come up with one other. Some have 2002, and some have 2004, and a few have both, but there seems to be a gap. Did FHI just skip a year of electrical engineering for the US 2003 model year? Or is the internet just letting me down?

FSM?

There were very few changes of any form 2002-2003. The only thing I can actually recall that changed was front brake calipers and that was a mid-year 2002 change.

A dealership should be able to look up the part number for each. 2004 is probably a bit different.

Factory Service Manual?

Yes.

I've never seen 2003 specific manuals.

Here's a nice little compilation though. http://ken-gilbert.com/impreza-manuals

Yeah, the funny thing is, I KNOW there's an extra pin on the '03 ECUs compared to '02, so at least one wire difference in the bulkhead harness. Otherwise, should be the same. What I really need to know though is if there are changes in the front and engine harnesses.

wasnt there an abs change in 7/02?

I thought that was just a programming thing.

ABS software change for '02-'03 cars and I think was made in '04. Front caliper changed late '02 model year, no brake related wiring change as far as I know.

There was a CSP that allowed you to upgrade to the newer ABS ECU. I was able to get it done before installing my SS lines.

There is no ABS ECU. Just the ECU, which got reflashed, not replaced AFAIK.

No, there is one and they replaced it. ECU, in this case, stands for electronic control unit. Read the letter here:

http://www.seccs.org/forums/showthre...hlight=abs+ecu

I think that refers to the pump unit itself. Now that I think about it, I guess it has to have some serious onboard electronics, given all the wiring going into it.

Control Unit would not be a pump.

Or maybe not... down in that thread you refer to it costing $280, and the pumps are like $900. Now I'm confused. So where the hell is this thing? I've never seen anything I would think was an ECU in one. I haven't wrenched on many WRXs though.

That I don't know.

The ABS pump under the hood has the "ECU" built into it IIRC. I thought the firmware upgrade was swapping an EPROM out for one w/ the new program.

Scott's right. ABS Control Unit and pump are one unit.