Quick question - where is the ECU located on a '95 Legacy wg

Gus · Post by **Gus** » Sun Mar 27, 2005 12:10 am

I'm on my way out the door to help my neighbor who's mechanic thinks his ECU is toasted. I'm going to plug my OBD scanner in and see if I get anything. Supposedly his mechanic couldn't. Anyway, anyone know where I might find the ECU on a '95 Legacy Wagon? I'm going to check my Haynes manual, but who knows what that will tell me.

Thanks

vrg3 · Post by **vrg3** » Sun Mar 27, 2005 12:15 am

The ECU is under the carpet in front of the passenger seat. The OBD-II port is under or in the panel right above the driver's knees.

Gus · Post by **Gus** » Sun Mar 27, 2005 12:22 am

Thanks buddy!

vrg3 · Post by **vrg3** » Sun Mar 27, 2005 12:24 am

No problem.

Gus · Post by **Gus** » Sun Mar 27, 2005 2:16 am

Yeah, that helped. Now I just need to figure out what to do. I plugged my OBD scanner in and it wouldn't connect, just like the mechanic's wouldn't. So we pulled the ECU and there was some standing water on his floor -yeah, when I told him where the ECU was located he was like uh oh. However, once I pulled it, it all looked clean and dry, connectors and everhything. So out of curiousity, I popped the cover to look inside and it all looked clean and dry. No residue or anything. Nothing looked or smelled burnt. Not that that means anything, just an observation. So I guess there's one other thing to check before having him buy a replacement ECU and that would be to verify that power is making it to the ECU and something didn't cook upstream. The Haynes schematic isn't very helpful. Any idea how I can test for power to the ECU or do you know of anything else that would cause these symptoms? The ECU light started flashing one morning and the car died shortly thereafter. No spark, no fuel, no OBD response. It just cranks. The fact that there's no OBD response, leads me to believe that there's really no point in any further troubleshooting beyond the ECU and it's power source for the time being.

Also, where is a good place to start looking for a used ECU? I hear the '95 ECU is specific to the '95 MY.

Thanks

vrg3 · Post by **vrg3** » Sun Mar 27, 2005 2:50 am

A lot of not-well-designed scantools (which includes many of the more cost-effective ones out there) fail on 95 Legacies, and even some later ones, in my experience...

It's certainly possible that the flooding caused damage to other parts of the wiring harness or something.

Does the Check Engine light turn on when the ignition is turned on? That's the most basic check to see whether the ECU is getting power.

I think you can also connect a pair of green connectors somewhere under the dash to turn on a test mode that makes the ECU cycle the various relays and solenoids on and off.

Yes, the 95 ECU is very different from any other year. 5-speeds and automatics are the same though. You could try looking on car-part.com.

Gus · Post by **Gus** » Sun Mar 27, 2005 3:09 am

I've used my OBD scanner to pull codes off this car before, so my scanner has worked with this ECU before, for whatever that's worth.

I don't believe the check engine light was on when the ignition was on. I should have paid closer attention, but I glanced up to see if I saw any flashing yellow and I only saw red. I'm pretty sure it wasn't on.

So this OBDII car might have the same green connectors as the OBDI cars? I'm familiar with that process.

Ok, thanks for the tips.

vrg3 · Post by **vrg3** » Sun Mar 27, 2005 3:51 am

Okay, if your scantool worked before and the CEL doesn't come on, then the ECU's probably not powering up.

You can try checking the power supply pins:

http://www.graphics.cornell.edu/~v/95pinouts.html

Have you already checked SBF-2 in the underhood fuse box?

Gus · Post by **Gus** » Sun Mar 27, 2005 5:31 am

Ok, good to know.

Sweet. That will help. Looks like I need to check pins 15&16 for 12v and 95&96 for ground?

My troubleshooting on this car has been limited to everything I've posted thus far (not much). I've taken the owner's mechanic's word for everything else. He seems knowledgeable, but isn't familiar with Subarus. He's supposedly checked all fuses and fusable links. I don't have my book handy, what is SBF-2, a fusable link?

Thanks

vrg3 · Post by **vrg3** » Sun Mar 27, 2005 5:36 am

I'd also check for ground at all the other ground pins just in case too.

SBF-2 is one of the big green slow-blow fuses in the underhood fuse box. Pretty much all the engine management stuff is powered through it.

Gus · Post by **Gus** » Sun Mar 27, 2005 5:49 am

OK, I'll try to check that tomorrow and get back to you. Hopefully that's all it is. That would be nice.

Thanks

Gus · Post by **Gus** » Thu Mar 31, 2005 2:56 am

Ok, SBF-2 tested OK and there's 12V making it that far, but I could not get any voltage rating at pins 15 & 16 on the ECU wire harness. I triple+ checked everything and even opened the ECU back up to put the meter on the exposed contacts for 15 & 16 within it and got nuthin. I also checked continuity of the ground pins from the harness and didn't get anything, but that test is less conclusive since I'm not sure if the pin on my meter was actually making contact with the metal in the harness plug and due to the pin location within the ECU, I was unable to test it from within.

Now I'm not too optimistic about this car. Is there anything else I should check or is there any other reason that I wouldn't be getting 12v at these two pins? The wire harness, from what I can see looks ok, but without really tearing into it, it's hard to tell. Are we sure that pinout is correct? I mean, unless there's another fuse or plug or something inline, I'm out of ideas.

Thanks

Gus · Post by **Gus** » Tue Apr 05, 2005 1:17 am

Anyone have any ideas on this one? The guy is stuck w/o transportation and I'm stuck w/o ideas. Anyone know if the other end of the ECU wire harness terminates in one place such as the engine bay fuse box? Short of trying, and possibly frying, a new ECU the only other thing I can think of is tracing the harness wires and that's easier said than done, especially when you don't know where exactly they go.

Thanks

vrg3 · Post by **vrg3** » Tue Apr 05, 2005 7:47 pm

Dumb question -- you're not looking at the connector backwards, are you?

What colors were the wires at those pins?

Gus · Post by **Gus** » Tue Apr 05, 2005 8:05 pm

I had to double-check the pinout, but no, the only way I could have been looking at it backwards is if it were upside-down and I know that's not the case since I was basing the pinout off the offset on the left side. Not sure what colors the wires were. Seems like maybe one of the positives was gray/red? I could go back over and find out though if it would help.

Thanks

vrg3 · Post by **vrg3** » Tue Apr 05, 2005 8:30 pm

The connector is horizontally symmetrical, right?

I would expect the power wires to both be the same color... Yellow/red or maybe just yellow or something. And the grounds to be the same color, too. Maybe black/red.

Gus · Post by **Gus** » Tue Apr 05, 2005 8:45 pm

Yeah, it is symmetrical. That's how I know that I wasn't looking at it backwards, etc.

I'll try to get a closer look at the wires to determine their colors.

Thanks

Gus · Post by **Gus** » Wed Apr 06, 2005 3:36 pm

Ok, I had the owner check the ECU wire colors and here's what they found:

#16 power supply-light green with black specks
#15 power supply-brown with lighter colored specks
#42 backup power supply-NO WIRE AT ALL
power supply ground wires
#95 and #96-black wires with lighter colored stripes

lighter colored meaning possibly white

Thanks

vrg3 · Post by **vrg3** » Wed Apr 06, 2005 4:07 pm

Uhh... hmmm... that don't seem right. That sounds like he's looking at it backwards. For example, the Injector 2 wire (pin #1) ought to be light green. And the Injector 1 wire (pin #2) ought to be brown. These are the mirror-image corresponding pins to #16 and #15, respectively.

Gus · Post by **Gus** » Wed Apr 06, 2005 4:26 pm

That's interesting. I'll have him double check. I printed a copy of this:

http://www.graphics.cornell.edu/~v/95pinouts.html

Then highlighted 16 & 15 and pointed out the shape of the harness, so I can't imagine -oh, maybe he was looking at the back side of it. Perhaps I had it backwards when I put the meter on it. I'm assuming though, this diagram is illustrating what the wiring harness looks like if you pulled it off the ECU and looked into it. That's not the case though, is it? This diagram is of the ECU itself. Ah. Is that correct?

Thanks

vrg3 · Post by **vrg3** » Wed Apr 06, 2005 4:30 pm

Yes, it's of the ECU itself. I'll add a clarification.

Gus · Post by **Gus** » Wed Apr 06, 2005 4:32 pm

Well, I'm an idiot. Ok, time to take my meter back over there.

Thanks

Gus · Post by **Gus** » Thu Apr 07, 2005 3:21 am

Ok, on the ECU pinout re-check from the owner of the car:

wires 15 and 16 are yellow with a green stripe
red is the backup wire

Does that sound more like it?

Thanks

vrg3 · Post by **vrg3** » Thu Apr 07, 2005 3:22 am

Yeah, that sounds like it might be right.

Gus · Post by **Gus** » Thu Apr 07, 2005 3:30 am

Ok, I don't know when I'll be able to get back over there to put my meter on it, but meanhwile, someone over at USMB might have an ECU for me so I may just go ahead and get that.

Thanks

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Quick question - where is the ECU located on a '95 Legacy wg

Quick question - where is the ECU located on a '95 Legacy wg

Thanks!

Found it.

Interesting...ok...

OK...

New finds...

Any ideas

No...

Wire colors

Pin-out

Doh

Wire colors

Thanks