P0420 Help (Civic Si 2017)

[Naimahab]

I installed a catted MAPerformance DOwnpipe, and after like 50mi I got the ECL P0420 Code, so naturally I cleared it on My Ktuner. Now it keeps coming back, how do I get rid of it permanently? Yes everything is tight and sealed properly

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[xjoshuax89]

gotta use ktuner to disable the code not just clear it.

 

[Naimahab]

gotta use ktuner to disable the code not just clear it.

how do i do that

 

[gtman]

When you set up a tune in the KTuner software, go to Disables/Monitors. Under Options, put a check next to P0420. Then upload the tune to your ECU.

 

[Joev492]

This is what you're looking for. I think the bottom (O2 Sensor Slow Response) is for the CAI Race though.

 

[Naimahab]

This is what you're looking for. I think the bottom (O2 Sensor Slow Response) is for the CAI Race though.

thank you so much

 

[bcrichster]

I installed a catted MAPerformance DOwnpipe, and after like 50mi I got the ECL P0420 Code, so naturally I cleared it on My Ktuner. Now it keeps coming back, how do I get rid of it permanently? Yes everything is tight and sealed properly

Try this.. mini cat for O2 sensor. ?
https://www.amazon.com/dp/B0861522YZ/ref=cm_sw_r_cp_apa_i_UwkLFbRE8ZP88?_encoding=UTF8&psc=1

 

[hobby-man]

This is what you're looking for. I think the bottom (O2 Sensor Slow Response) is for the CAI Race though.

No, downpipes will throw P0138/P0139. I get that one with my 27WON catted DP without it disabled. Never saw a P0420 though.

 

[gtman]

You wouldn't think a catted downpipe would throw a catalyst efficiency code.

 

[Joev492]

No, downpipes will throw P0138/P0139. I get that one with my 27WON catted DP without it disabled. Never saw a P0420 though.

This was directly what TSP customer service recommended for my installation of PRL catted DP and Race CAI

Hasn't thrown any codes with this either.

 

[BrandonSmith]

Make of it what you will!

 

[bcrichster]

http://techinfo.honda.com/rjanisis/.../SC/SYS/A007909_enu/web/html/A007909_enu.html

Make of it what you will!

Won't let us read it..

 

[BrandonSmith]

Oops... Here you go

 

[bcrichster]

Oops... Here you go

Ty-!

 

[Hervacationhome]

I recommend you try to address the issue rather than just ignore it. Your car is throwing an inefficiency code for a reason. Ignoring it will only lead to detrimental permanent issues in the long run. Try putting a defouler on it.

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