HELP PLEASE!! - P0031 check engine light after car wash!

[astrange22]

HELP! I recently went stage 2 (Invidia Catted DP) on my 2016 STI, and got a tune from Eric @ Torqued Performance. This will be my 3rd subie with his maps and they are great.

I took my car to the touchless car wash to spray the salt off of the bottom of the car and while in the car wash, my check engine light came on. I have been stage 2 for a few hundred miles with no issues. I read a lot about the error and most say it could be a bad sensor or issues with a short in the wiring. It keep popping the fuse. I figured there was an issue with the wiring getting wet or something.

I first checked the wires and they were good . I replaced the fuse, cleared the code and it popped again. I then replaced both the front and rear sensor and replaced the fuse and cleared the code. It popped again as well. I am stumped where to look next.

Any ideas would be great!

Thanks,
Adam

 

[HolyCrapItsFast]

May I ask what fuse exactly was blown and what was the engine code that came up :tup:

 

[Grinder34]

Ditto on what Holy said. Without that info it's like taking a shot in the dark.

 

[astrange22]

Sorry, forgot that part. The code is P0031 and the fuse is for the o2 sensor. It is the 15 amp fuse 7th down on the right side of the fuse block on the drivers side (inside of the car).

 

[HolyCrapItsFast]

Well I would start by unplugging the o2 sensor and blow out the connector with a can of dust cleaner or contact cleaner. Before you plug it in again, replace the fuse and turn on the ignition and check the fuse did not blow.

If it does blow then there is an obvious short some where in the harness but you will have to trace it to find it. You could then unplug the main engine harness connectors by the battery and blow them out as well and check it again.

Else if the fuse does not blow, then plug the O2 sensor back in and check the fuse.

If the fuse blows then the sensor needs replacing.

If it does not blow then reset the ECU and check for the code.

 

[astrange22]

Thank you so much! I will try that tomorrow and see how it goes.

-Adam

 

[HolyCrapItsFast]

Please let us know how it goes :tup:

 

[astrange22]

I disconnected the front o2 sensor, blew out the connection and replaced the fuse. The fuse still blew with out the o2 sensor connected. I checked all of the connections that I saw and knew of and everything looked good. Where is the main engine harness to check? There is a big harness above the turbo but wasn't sure if that was it. It has a slider clip holding it connected.

 

[HolyCrapItsFast]

Oh yes... that big connector near the turbo is the main engine harness. I keep thinking GD.

Okay so you have a shorted wire somewhere. Give me a few moments and I will make more suggestions when I familiarize myself with the 2016

 

[HolyCrapItsFast]

Can you point out the exact fuse that is blowing below....

 

[Raven32]

Can you follow the wire connected to the front 02 sensor and see if there is any damage to the wire. I was reading on this on some other forums and common issues are, melted wire due to 02 sensor wire being close to up pipe/headers, and another one was an issue with the connector in the fuse block. I would start by disconnecting the front 02 sensor and following the wire harness looking for signs of melted wire/melted wires in the lume. How does the fuse blow, as soon as you turn the ignition on or little while after? My thoughts is that water jets moved your wire close to a header and might of melted a wire, but thats just a guess with out more information or pictures.

 

[astrange22]

It is the fuse on the right side (vertical stack), 7th down from the top. It is a 15amp fuse. It blows every time is turn the key. I checked the wires and didn't see any issues and even replaced the O2 sensor. Is there a relay behind that fuse box that might be out? I was reading somewhere and saw that. Wanted to make sure before I started trying to remove fuse boxes.

Thanks again for everyones help! I love this site!

 

[astrange22]

It is the 5th fuse from the top in the 7th slot.

 

[Raven32]

Same did not work. I use tapi talk for pictures


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[astrange22]

I changed the permissions on this to public, lets see if it works.

 

[Raven32]

Yes it did


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[Raven32]

What's the embossed number next to the fuse. If you look close there's a number embossed next to the fuse


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[Grinder34]

so are you saying this one?

 

[HolyCrapItsFast]

Well that is definitely the O2 sensor fuse. There is also a relay associated with it. If you can locate that relay and unplug it and then see if the fuse blows, That is a clue.

To be honest I would bring it to the dealer and see if they can fix it under warranty. Just play dumb and don't tell them you washed anything.

 

[astrange22]

Sorry, been out of town. Yes, that is the fuse. Do you think I would have an issue being stage 2 with the warranty? I thought about that but wasn't sure if they would deny it for that.