• A large amount of updates and changes have been implemented. Users who have been using tapaptalk will need to access the site in their phone browser. You should see a big difference between the desktop/tablet/phone styles to make navigation and site options easier to use. If you come across any strange behavior, or errors, please report them in this thread. If you have any issues logging into the site, please delete all 9thcivic cookies and then log into the site. https://9thcivic.com/forum/threads/site-changes.16518/

Trying to pass inspection and failing. Code P0139

webby

Administrator
Admin
Toys For Tots
52,735
22,640
if they hook it up to obd2, you're not going to pass with your code...or having it disabled. Call rv6 and find out warranty info on the cat? If you need to pass immediately, swap out to oem. There isn't much else to do.
 

dpetro1

Well-Known Member
you shouldn't need a defouler if you have a catted downpipe. remove the defouler, make sure the secondary o2 is not disabled in flashpro, clear the codes and see if they come back.

also, make sure the sensor is plugged in tightly and the wires didnt get cut or something random like that
 

Nomar06

Super Moderator
Super Mod
Toys For Tots
8,113
5,261
Charlotte, NC
Vehicle Model
Honda Civic Type R
Body Style
hatch
you shouldn't need a defouler if you have a catted downpipe. remove the defouler, make sure the secondary o2 is not disabled in flashpro, clear the codes and see if they come back.

also, make sure the sensor is plugged in tightly and the wires didnt get cut or something random like that

He will need the defouler on an aftermarket downpipe. The cat on an aftermarket pipe are way smaller than stock downpipe, causing the car to throw a code.


I would disable the secondary O2 and see where that gets you....but yes, check the wires if the secondary O2 is "on".
 

dpetro1

Well-Known Member
He will need the defouler on an aftermarket downpipe. The cat on an aftermarket pipe are way smaller than stock downpipe, causing the car to throw a code.

That has not been my experience as I have a full-race catted dp and exhaust. No defouler, no CEL. Seems like others below have not experienced CELs either while using a catted DP and no defouler. Having a cat and a defouler is likely causing too much variance in the o2 reading causing the code

Um... I had my intake, catted dp, and exhaust without flashpro or a tune and I didn't get a code...

No, it will not throw a code. I have just DP and exhaust, all FullRace, no flash pro or defouler and I've never thrown a code. Had this on for over 15,000 miles now. I also have the catted downpipe.

A non catted downpipe will throw a code.
 

squiggy

Cartographer
Super Mod
Toys For Tots
11,234
6,691
Michiana
Vehicle Model
Toyota MR2 Spyder
Body Style
Convertible
That has not been my experience as I have a full-race catted dp and exhaust. No defouler, no CEL. Seems like others below have not experienced CELs either while using a catted DP and no defouler. Having a cat and a defouler is likely causing too much variance in the o2 reading causing the code

I have a catted FR DP without a defouler and my car will throw a code.
 

NoTorque

Active Member
40
11
I think you're on to something because basically the code I'm getting p0139 is a slow response code, which means it's not getting enough gasses. Most likely because it's too far away in this angled defouler.

I've tried stock tune, hondata reflash, and vit tune with o2 on and they all have the same code. P0139. I've also tried turning the defouler and screwing it in all the way.

I honestly dont know what the sensor should be reading but when I check the reading of the sensor it shows 0.87 volts at idle and then light revs it actually goes down, often to very low numbers like 0.1 then it takes a while to come back up so I'm guessing that's where the code is coming from.


Edit: well I took off the defouler but honestly I don't see this working because the o2 sensor is before the cat


Edit2: in inspection right now I'm pretty sure this is fail
 
Last edited:

Nomar06

Super Moderator
Super Mod
Toys For Tots
8,113
5,261
Charlotte, NC
Vehicle Model
Honda Civic Type R
Body Style
hatch
I think you're on to something because basically the code I'm getting p0139 is a slow response code, which means it's not getting enough gasses. Most likely because it's too far away in this angled defouler.

I've tried stock tune, hondata reflash, and vit tune with o2 on and they all have the same code. P0139. I've also tried turning the defouler and screwing it in all the way.

I honestly dont know what the sensor should be reading but when I check the reading of the sensor it shows 0.87 volts at idle and then light revs it actually goes down, often to very low numbers like 0.1 then it takes a while to come back up so I'm guessing that's where the code is coming from.


Edit: well I took off the defouler but honestly I don't see this working because the o2 sensor is before the cat


Edit2: in inspection right now I'm pretty sure this is fail


You should have 2 O2 sensors....one before the cat and one after the cat. Your car will measure gasses before and after the cat, this is how your car tells you if the cat is property working or not.

The defouler should be on the O2 after the cat.
 

NoTorque

Active Member
40
11
You should have 2 O2 sensors....one before the cat and one after the cat. Your car will measure gasses before and after the cat, this is how your car tells you if the cat is property working or not.

The defouler should be on the O2 after the cat.
On the stock downpipe you have one o2 sensor at the top right after the manifold and then one after the first cat

On the rv6 you have one at the top and then one right before the cat (first cat is deleted). That's why it usually throws the code even though it's catted you don't have a cat before the o2 sensor.
 

NoTorque

Active Member
40
11
Major update:

Just passed!

I went to a fast lube place, thinking they would be cool.( I don't have a regular shop since I do my own work)

They were trying to fail me it seemed. Even checked my tint even though it's obviously legal, were looking under the car and all from the bay underneath. Checking under the hood for everything. Opened all the doors and trunk (saw my flashpro in there, yikes)

So here is what I did. I tried the angled defouler with the stock, hondata reflash, and vit tune and it gave me the same code p0139 (low voltage or slow response). Basically means the o2 sensor isn't getting enough gasses so the reading isn't matching up to what the computer thinks which without a defouler would mean the o2 sensor is broken or there is an exhaust leak preventing gas from reaching the sensor.

So ok I'm thinking how to get the exhaust more gas so I tried angling the defouler differently and made sure it was screwed in all the way (set screw at the beginning can be adjusted). Still didn't work.

Then I got a short defouler. Honestly I think this would have worked except that my o2 sensor wiring was too short and it wouldn't fit. I thought I was screwed at this point.

Then someone mentioned going no defouler so I figured why not. I used the hondata reflash tune and drove around a bit (about 10 miles without turning the car off). No code surprisingly and my readiness codes were this: http://imgur.com/dhAE18N.jpg

I know you can pass with one incomplete and I knew the evap test seems to always be the last to complete. So I decided to go for it. Technically at this point it should pass a visual test because the o2 sensor is screwed in properly with no defouler and there is a cat on the pipe as well.

Well it did pass thankfully. My advice if you're having this problem would be try with no defouler or just reflash to stock or hondata reflash, drive around until you get only 1 incomplete and then bring it in without turning off the car because the code always pops up after you turn the car back on.

Another note: if you are running an aftermarket downpipe and not tuned then you need to get tuned asap. The car runs like garbage untuned. I have been tuned for a while now so I never realized how bad it was but if you have mods you need to get tuned.

Sent from my SM-N920V using Tapatalk
 

webby

Administrator
Admin
Toys For Tots
52,735
22,640
I'd put your defouler back on the car now that you've passed. O2 Sensors are known for going bad in aftermarket downpipes, and it's probably even more likely with the rv6 design. With the o2 being before the cat in the rv6, it will likely kill that o2 sensor. It's a lot easier swapping the defouler next time you have to be checked versus buying a new o2.
 

NoTorque

Active Member
40
11
I'd put your defouler back on the car now that you've passed. O2 Sensors are known for going bad in aftermarket downpipes, and it's probably even more likely with the rv6 design. With the o2 being before the cat in the rv6, it will likely kill that o2 sensor. It's a lot easier swapping the defouler next time you have to be checked versus buying a new o2.
Yeah good call. I guess they don't call them deFOULers for nothing
 

dpetro1

Well-Known Member
I'd put your defouler back on the car now that you've passed. O2 Sensors are known for going bad in aftermarket downpipes, and it's probably even more likely with the rv6 design. With the o2 being before the cat in the rv6, it will likely kill that o2 sensor. It's a lot easier swapping the defouler next time you have to be checked versus buying a new o2.
I did not realize rv6 was designed that way. Kills my argument re: not using the defouler. Seems like a poor design
 

Mikeorock

Well-Known Member
424
88
queens, ny
Vehicle Model
civic si
Body Style
coupe
Anyone know why my o2 sensor will not complete? I've had it enabled for a while now and it won't complete
 
Top