[stc75]

I've gotten a lot of help off of this and other forums over the years and might have come across a problem/solution that could be helpful to others.

Car is 2007 Outback 2.5 with just about 200,000 miles. I was getting CELs and very hard starts. I've been having gas cap codes (especially after filling up) so I started carrying a small, cheap code reader to clear those and then one day my cheap code reader wouldn't work any more. I had been using the car on some long trips and often the code would clear by the time I got home and I would forget about it but I tended to notice the hard starts and CEL seemed to come during heavy rains and moist periods. The other day the code remained when I got hom and I tried my big Autel code reader and it wouldn't power up either. Using the external power on it I was able to power up the code reader and get the P1560 code.

I checked voltage at the OBD port (pin 16) and only had 6 volts (it varied as high as 10 and as low as 2). I checked the power at the ECU (B135 pin 5) and also had low voltage there. When I was checking these voltages I was using a variety of grounds to make sure it wasn't a ground issue. I had very low resistance between the ECU and the OBD port but high resistance between the port and Fuse 13 under the hood.

The wire comes from the fuse block and then splits right above the OBD port to go over and feed the ECU. I cut that split out to make sure it wasn't the issue and it wasn't but that also helped me confirm my problem was between the OBD port and the fuse block. I also pulled the fuse block out and checked resistance between the fuse socket on top and the wire pin on the bottom to make sure everything was good there.

Finally I pulled the inner fender off to get access to the harness where it enters the cabin of the car and there was the problem right in front of me. The wire harness makes a corner to enter the cabin and the wire for the OBD port and ECU were on the outside of the harness and had gotten worn through.

If you're having any troubles and it could potentially be in this harness I'd suggest looking there first. I only found one other person (on the NASIOC forum) that had a similar problem (also in moist conditions) but he just ran a jumper wire from his always on stereo power to the ECU which would fix the immediate problem but could cause some issues down the road.

Thanks

 

[plain OM]

@stc75

Welcome, and thanks for reporting that interesting find. (Great troubleshooting as well!)

I presume the cable/harness is wrapped where it passes through that area under the fender on its way to the entrance to the cabin. Any idea what the harness was rubbing against that wore through the outer covering (wrap) and the white back-up power wire?

I'm wondering if this could have been due to misplacement of the harness, either originally, or perhaps as a result of a collision and subsequent body work. The harness should be clear of any sharp surfaces, and is supposed to be protected by a rubber grommet/seal where it goes through the sheet metal into the cabin. (see attached)

 

[stc75]

The harness is wrapped but it didn't go low enough, the wear happened right at the edge of the wrapping (I had to cut it back to get the bad section of the wire out). We've owned the car since new and it's only been in a body shop once but I can't remember if they had the fender off or not. Even if they had, you could remove the fender w/o really displacing the harness. It has one of those annoying zip ties with a plastic nut that holds the harness up against the door frame using the back of the bolt that holds the door checker assembly.

I think it's just a combination of the harness being held up against that door frame by the zip tie, a tight bend in the harness, and not enough wrapping. . . .plus 200,000 miles.

 

[relative4]

Nice work, thanks for posting.

 

[ASubaruApprentice]

Thank you! This was my problem!

 

[Mike Boldi]

YOU .....My friend....R the Man....MINE.....2...👍