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Discussion Starter · #1 · (Edited)
P0031 confusion

So I finally got my car put back together after installing new headers, 02 sensor, and BPV recirc hose. The car sat for 3 weeks during all this work. Finally when I went to start it, I got a P1507 for the IACV malfunction (fail safe) and a P1130 for the 02 Sensor. The 02 sensor is brand new and I cleaned the IACV and got a new gasket, went over and looked for vacuum leaks couldn't see any. I've heard that after sitting for a little the IACV can get stuck but it can be freed up, anyone know how to do that? Or any advice for my situation here?
 

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I would use maf cleaner, or brake clean in it

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I would maybe try electrical contact cleaner as well. It dries residue free and we use it at work on tools with various sensors because it cleans crud off like brake clean but can be used around and on electronics.

The O2 sensor may be related somehow maybe a loose harness, I wouldn't worry about it right away but I wouldn't drive the car with a possible bad front o2.

Have you done any work recently that would have jostled the wiring around?

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Discussion Starter · #5 ·
I would maybe try electrical contact cleaner as well. It dries residue free and we use it at work on tools with various sensors because it cleans crud off like brake clean but can be used around and on electronics.

The O2 sensor may be related somehow maybe a loose harness, I wouldn't worry about it right away but I wouldn't drive the car with a possible bad front o2.

Have you done any work recently that would have jostled the wiring around?

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Luckily I just got my Cherokee registered and can dedicate my Subaru as my project car. Yes there was definitely work that would jostle the wiring around. However, wiring for the 02 sensor is relatively straight forward and seems to be installed correctly. I won't be driving it any time soon to my dismay, have never not driven it for this long I feel like a part of me is missing.

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Discussion Starter · #6 ·
Ok so the new IACV I bought and installed fixed my p1507 and eliminated my high idle so that's good. The p1130 is still being thrown but now it's also throwing a p1139 for the 02 sensor range being off. So I believe these two are telling me it's in open circuit right now and I'm gonna do a check with a multimeter to determine whether i have a wrong part/bad sensor or a bad connection. Will report back.
 

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Discussion Starter · #7 ·
Alright so I'm still hunting down why i'm getting codes for my 02 sensor. I believe I bought the right Denso part, here is a link to the sensor I bought and it has the same part number listed for the denso sensor for the 02 WRX. I checked the resistance on the top two pins of the sensor and they seemed fine indicating the sensor wasn't bad.

NEW DENSO OEM A/F Air/Fuel Air-Fuel Ratio Sensor 234-9011 2349011 USA | eBay

I cleaned the contacts for the plug with maf cleaner. Still throwing the code.
 

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Discussion Starter · #8 · (Edited)
Ooooh ok I learned I could have a heater circuit fuse blown. Only thing is where the **** is it?? Lol I've heard it's under the passenger dashboard but I looked and didn't see nuttin

Edit: So I learned there are no fuses under the passenger dashboard on a bugeye lol but I checked the fuses under the hood and they all look good. Is there a relay I could check for the 02 sensor? Gonna see if I'm getting power to the sensor in a second. Very hot and humid today, making just checking fuses a chore.
 

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Discussion Starter · #9 · (Edited)
Alright so I only get power to one of the heater wires from the harness. Specifically this is the only pin i get power from, the top left one. Would that be why it's saying it is in open circuit or is this normal?

Edit: this is normal however still don't know why it's throwing the code???

 

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Discussion Starter · #10 · (Edited)
So today I got to the heart of my bugeye! Did the diagnostic testing in the FSM and sourced back to my ECU. So far I have gotten to this step in the FSM



I tested the 02 Sensor and the resistance is in the acceptable zone so I don't think that's the issue. So, I realize its possible I could have a borked wire somewhere due to having to jack the engine up a couple times. Any tips on where to look or how I should go about this?

Edit: Only code the car is currently throwing is a P0031 - Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)
 

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if i remember right mine has a black shroud leading up to the plastic. What you have just looks wrong. Totally wrong. Those look like the wrong size of wires leading to the harness. To me it seems like the previous owner scraped up the wiring and did a really shoddy job of rewiring. Wires exposed+that funky blue tape job is not right.
 

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just took a quick peek and pulled back the shroud and some of the electrical tape. mine looks like how subaru would have made it from the factory



just looked at previous pictures to see the cover you had for your wires and it was red... so that means it has been messed with 100% and I think you're going to find yourself running new wires from whats left of your harness wiring, all the way back. another edit: just looked at the wiring again and it looks like your white and black wires have been fused together? I've got 4 wires connecting to my harness. Looks like the harness is wired wrong It definitely looks like bad wiring to me. The one wire with copper hanging out really irks me, why would they have used that size of wire... it's not that hard to find wire that will be the same as the stuff that's there
 

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Discussion Starter · #14 ·
just took a quick peek and pulled back the shroud and some of the electrical tape. mine looks like how subaru would have made it from the factory



just looked at previous pictures to see the cover you had for your wires and it was red... so that means it has been messed with 100% and I think you're going to find yourself running new wires from whats left of your harness wiring, all the way back. another edit: just looked at the wiring again and it looks like your white and black wires have been fused together? I've got 4 wires connecting to my harness. Looks like the harness is wired wrong It definitely looks like bad wiring to me. The one wire with copper hanging out really irks me, why would they have used that size of wire... it's not that hard to find wire that will be the same as the stuff that's there
Hmmm still stuck with this predicament. I've been told that the white and black wires (sensor circuit wire i believe) are inside of that larger exposed wire in order to cut down noise and get accurate readings. However, my heater circuit wire (which is what the code was thrown for) has been cut an spliced back together. Thinking this yellow/red wire is the culprit and the actual exposed copper jumble is actually oem. I think if you stripped your harness down a little more you might find the same thing.
 

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I tried pulling and messing with the shroud on it, I can get up newer pictures if you'd like, but they look essentially the same. I didn't feel like cutting the shroud on it to get a better look... The taped black+white wire still feels like 2 wires to me underneath the tape, but they taped it pretty thick so I can't totally tell. You could be right that they are wired together but it doesn't make much sense to me.. Something definitely seems screwy though. I'd say check out the yellow/red wire first. The thick light purple wire seems off to me, but if you fix the yellow and it works I'd say fix the exposed wires issue on the purple and call it a day.
 

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Discussion Starter · #16 ·
I actually found another thick light wire in one of the other harnesses on my car while trying to diagnose this. So I believe my issue might be in the yellow wire or something else IDK lol. But yeah I agree this whole harness seems really shoddy and weird.
 

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Discussion Starter · #19 ·
Was there a solution? Was the exposed copper wire responsible for P0031 or P1130?
Yeah it turns out my harness was fried and burnt through at one point. So a patched harness and new 02 sensor set me straight. Although the 02 sensor might not be needed depending on your position, but mine was on its way out.
 
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