Wiring Harness chewed by rats

[Tucsondave]

New to forum, and still learning how to navigate around.

Took my 1015 Legacy to dealer for check engine line with flashing cruise control. -

Diagnosis: Pack rat chewed through wire. paper work says "knock sensor circuit"

Fix: Entire new wire harness

Problem: Harness not available, and no eta on when they may be. +++ Cost of $1,400

So I basically can't get this fixed for an indeterminate period of time, and won't be able to pass smog and get registered with a check engine light on. I took a look , and see a chewed wire coming out of harness, and two wires going into a connector right behind and below the AC compressor.

I need to get this fixed somehow. Can I solder these? If there are two coming out of the connector, any help on where they connect, since I see only one coming out of the harness.

 

ANY help greatly appreciated

 

Edited December 6, 2022 by Tucsondave
replace pdf with jpg

[ammcinnis]

If the gnawing is localized, you should be able to scavenge a usable replacement connector (with pigtail wires attached) from a salvage vehicle. The wires are color coded, so you should be able to splice the replacement connector into the existing wiring harness. Yes, soldering and insulating the splices is mandatory. If you don't want to do it yourself, any good tech should be able to do it for you for a nominal charge. I'm not sure why the dealer didn't suggest it.

If you don't already have one, a Factory Service Manual is invaluable in situations like this. Good luck.

[Max Capacity]

Yes, most any local car repair shop can splice that back together if you can't DIY. 

 

I-wire may have something too.

 

https://iwireusa.com/collections/1-2-pin-replacement-plugs

[Tucsondave]

That I wire link is great. Thanks for posting it. I’m not even sure, tho that the chewed wires shown in the pic are to the knock sensor. I read that off the dealer service report. 
since I only see one wire coming out of the harness, yet two wires going into that plug, anyone have suggestions on what’s up with that?

thanks again for the input

 

[silverton]

What you're labeling as a single wire, is a protector sheath covering the two wires. Unfortunately subaru doesn't put the sheath all the way down the harness which leaves the tasty wires exposed near the sensor.  Cut back some of that sheath and you'll see both wires, just use caution so you don't lose any more of your knock sensor wires coming from the main harness. 

The iWire plugs are great! Highly recommend.

[Tucsondave]

Thanks everyone for the responses.

I swore I wouldn't work on this car myself. I've got no problem tearing into my other car, but it's more than 60 years old, and has no computers...

But no choice if the dealer says they won't fix the wire and they can't get a harness. I'm all set to order the plug and pigtail from Iwire, once I confirm which plug it is (plug H I think, but have to pop it off to confirm). I'm pretty confident I can crimp a wire...

The other bad news the dealer gave me is they say I need both rear wheel bearings. It sounded like a little rock rattling around between the rotor and the rotor shield on the right rear, but they say bearings. You tube makes this look way easier than it probably is. Has anyone done this swap who can tell me what can go wrong? Is it really just unbolt and rebolt? What can I screw up and not know? The dealer gave me a price of 1,200 for both. Any suggestions on replacement part brands?

Looks like I really only need to get a better torque wrench (you tube says 177 ft lbs on rear nut)

 

What can go wrong? 

Any help super appreciated

david

[Tucsondave]

Wiring update: 

instead of 2 wires in that one sheath, I found where the green wire stops (chewed by rat or cut by rats). 
gonna be a hard splice unless I can get some more slack. 

[silverton]

It's hit or miss on your wheel bearings being easy or not, some of them fall out, others take a lot of hammer.  But it is as simple as unbolting, pulling it out, and bolting a new one in.  You will need a slide hammer.

[Tucsondave]

So, Got a new knock sensor plug from Iwire. Couple hours (I'm slow and easily frustrated, so I walk away a lot) getting that little stub green wire stripped, and everything put back together...

 

Cleared the computer, and CEL is OFF!

So, if it stays that way, I'm more than $1,300 to the good. I pretty sure I'll order out rear wheel bearings and give that a go. Should be able to get a slidehammer from  autozone tool loaner. Probably have to buy a new torque wrench that will go to 200, as I think the wheel nut is supposed to be torqued to 177?

 

Thanks everyone for the input and words of encouragement. I'm happy

dave

[silverton]

knock sensor issues pop the CEL immediately so it sounds like you fixed it! good job buddy!

(torque specs in order of installation from alldata, install is always reverse of removal)

65nm(48ftlb) for the four 14's on the wheel bearing itself

66nm(49ftlb) for the caliper bracket bolts

33nm(25ftlb) for brake bracket hose

7.5nm(5.5..6ftlb) for wheel speed sensor

240nm(177ftlb) for the axle nut

120nm(89ftlb) for the wheel nuts.

 

When I do it I only take off the caliper bracket after the wheel is off and tuck the caliper assembly up and away.  I have seen the wheel speed sensor get broken multiple times by my cohorts, I have yet to so no idea what they're doing wrong, but it's better to be safe than sorry if you're doing it yourself.

[Tucsondave]

So, I went from Super happy to super frustrated again on the CEL....

I got the CEL cleared, and car ran fine. Except, after about 74 miles the CEL clicks back on and engine starts to run a lttle rough. Same Code - Knock Sensor P0327. I checked all the wiring, and no obvious change. I cleared the code and CEL off at 1st startup. I then unplugged the knock sensor, and CEL comes on immediately at start. Cleared the code again, and plugged the sensor back in and it was good for another 74 miles, then CEL again. I can't tell if the problem is my sensor, or the wiring I spliced in. The white wire to the sensor is shielded, and I've spliced in maybe 8 or 10 inches of unshielded wire. Can that be the problem? It would be hard to believe I had the wiring chewed through (giving me the CEL in the 1st place) AND a bad knock sensor at conveniently the same time....

would this length of unshielded wire be causing my problem? If so, is there a way to shield a wire that might work??

My path forward is to connect a new plug with pigtail to the sensor to check it. I hear that I should check resistance to be between 530-580 k ohms? Then check with multimeter set to AC, and tapping on the block to see if I get a reading? (you tube is great, but I never know if its the best place to get info...) I don't want to just start throwing parts at this, especially when it was so obvious the wiring was the original problem...

Is there another or better way to diagnose this issue? 

 

Again, ANY help or input is appreciated...

[Max Capacity]

 

Look for a post from  "Subarcharged" on March 17 2022, ask him. 

[ammcinnis]

1 hour ago, Tucsondave said:

I can't tell if the problem is my sensor, or the wiring I spliced in. The white wire to the sensor is shielded, and I've spliced in maybe 8 or 10 inches of unshielded wire. Can that be the problem?

Yes. If Subaru went to the trouble and expense of shielding that wire, you can be sure that it was important. The unshielded length of wire could act as an antenna for under-the-hood electrical noise. Did you even include a second wire to replace the shield? Besides providing electrical shielding, the shield may also serve as a ground wire.

Also, how did you make your splices? Crimped? Soldered? Other? You need secure, electrically transparent connections.

[waldguy]

On 12/18/2022 at 3:08 PM, Tucsondave said:

I pretty sure I'll order out rear wheel bearings and give that a go. Should be able to get a slidehammer from  autozone tool loaner. Probably have to buy a new torque wrench that will go to 200, as I think the wheel nut is supposed to be torqued to 177?

 

Yep, just be aware that a slidehammer may be insufficient.  Prying and hammering with an experienced mechanic took over an hour before mine finally unseated.  Yours will hopefully be easier.