This is a discussion on 2013 WRX P0451 Code Evap Emission Control System within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; Originally Posted by Cho.co.Pie Are all your cars stock or modified? I just hit 9k miles on my '13 wrx ...
Just another update from me. Turns out my code was somehow read wrong (wtf autozone) and they saw the P0451 from before my wiring harness ground(s) were re-soldered etc. Turns out my code was a P0455 from my gas cap being faulty. I am now over ~400 miles give or take with no CEL P0451 related issues since the re-soldering. Was also reassured that 3/4 cars that had the P0451 that came into the dealer and got the same fix as my car, the techs have not seen them again for the same issue since.
You guys that are struggling still, ask about the ground wire(s) etc. I'm pretty confident now that that is the problem!
Just realized I forgot to update this thread. The dealership replaced the entire wiring harness on October 2nd. I dropped it off in the morning, they had it done by the afternoon. No check engine lights since and everything appears to be running correctly.
I finally have an update as well! I took the car in a couple of weeks ago to get the codes looked at for the third time, but this time they checked the wiring harness. I took it in on a Thursday to get the initial testing done, then they said they would need it overnight, so I scheduled to bring it in the following Monday so I could get a rental.
Here’s the text from the initial service report on Thursday:
“NECESSARY TO REMOVE THE ENGINE HARNESS AND INSPECT FOR SHORT.
ISSUE IN HARNESS TO MAP SENSOR.”
Here’s the text on the report that I got when I picked up the car today:
“P0451 EXCESSIVE RESISTANCE IN B21 CONNECTOR CAUSING FAULT TO
SET. P0301-P0304 AS WELL.
REMOVED INTAKE AND REPLACED ENGINE HARNESS AS NECESSARY.”
For reference, the part number for the harness is listed as 24020AF070.
Hello, bringing this back up. I got the P0451 code, I cleared it, because I wanted to drive with my cruise control. I got home, parked for about 5-6 hours, went to leave and vehicle cranked but did not start. I tried starting it and it fired up finally after 4 tries...... I drove it ~40 miles and no codes came back yet, but its still reading not ready. I stalled it 3 times at different take offs, seemed weird. Idle seemed to be low RPM, almost shutting off when coming off gas pedal. Checked fuel cap first.
I wonder if I should wait for a code, or just take it in.
2013 WRX Sedan 18000 miles
Annnnnd I have a P0451 again. It's been about 10k miles since I last got this code, but at last, it's here again. So replacing the Leak Canister Valve didn't seem to completely fix the problem. Anyone have an update about the Engine Wire Harness being a "permanent" fix?
It permanently fixed my check engine light.
Ah ok so to update on my previous misfire experience back when I had 9k miles on the car (back in september). I thought it was a tune issue, so I got a protune done and for a while now that misfire issue hasnt come up yet. For the past month my engine idle has been running a bit rough even with the protune. I even got the P0300 cel. I talked to my tuner and even he couldnt figure out the exact cause. As I was planning on scheduling another appointment with my tuner so he can check it out, I remembered about the wiring harness issue. So I looked into it more and found out it was the Ground wire inside the wiring harness to be exact. Its a ground cable that connects to 4 other ground cables. That connection is just clamped on with some metal clip. So that was the cause of the misfire and rough idle. Instead of taking it back to Subaru to have them replace the wiring harness, I just cut open my wiring harness, found the ground cable connection, and added a bit of solder onto that connection point.. And right afterwards the car has been idling like a baby now. I fixed this problem last week when I had about 14.5k miles and since then car still runs like a champ. Usually I would get that rough idle everyday. If you guys dont have mods then I would say take it to the dealership, But I had full bolt ons and didnt want to risk getting denied warranty.
Last edited by Cho.co.Pie; 04-24-2014 at 02:58 PM.
Im going to bet its the wiring harness (grounding wire to be exact). Even though I only got the p0300 cel, fixing the wiring harness totally got rid of that problem.. Its lame how we pay this much for our cars, yet subaru cant ground them properly..
Okay cool, thanks for the replies. I only have an AP + Cobb Intake, so I might take my chances with getting the car fixed under warranty. Especially with my state inspection coming up, I need to get this fixed. With my luck, this CEL would come back right as I'm leaving to go get inspected.
Thanks again for the replies on fixes to this annoying problem!
heres the link to wrxforums from where I was able to fix it myself, if you ever do decide to do it for yourself. I think the OP of that thread also posted it on here and on nasioc as well. But I found that link to be the most helpfull since slushy explained to me on what to do. Im Chochocho on that forum.
13 wrx misfire issue...strange fix
Oh awesome link, if it's that simple, I'm definitely going to give that a try this weekend. The pictures are exactly what I needed