Background: I have a 2008 S2K that I installed a new Berk HFC and new Tanabe Revel exhaust on (a little over one year and ~3000 miles ago). Car won't pass emissions due to CEL P0420 that keeps popping up even after I clear the code using Hondata FlashPro. I tried disabling the secondary O2 sensor using the Hondata FlashPro but then, for whatever reason, my catalytic converter readiness would not ready no matter how much I tried driving the car (not sure if the disabling of the secondary O2 sensor had to do with this).

What are my options to keep the CEL P0420 from popping up so that I can finally get the car to pass emissions?

 

A de-fouler maybe the best option,i put my cat back on for the Test,otherwise takes 10+Mins holding at 4k rpm to get HFC hot to pass anyway.

 

Install an angled defouler that faces toward the front of the car. Meaning the secondary O2 sensor will face toward the rear of the car.

You will need to unclip the O2 sensor wiring harness completely in order to install.

Clip it all back in after you're done.

You will still fail a visual inspection. You will pass a plug in inspection.

 

Thanks. Can you please share with me a link to a angled spacer that I can buy?

 

I have the exact same setup and issue. I just put my stock cat back on. Let me know what angled defouler you buy to solve your issue.

 

A google search will find them.


https://www.walmart.com/ip/Car-Sensor-Angled-Extender-Spacer-90-Degree-02-Bung-Extension-M18-X-1-5-For-Any-Thread-Size-Of-18mm/329256930


They come as a kit with straight, long, short, and angled peices. Here's rhe orientation I use with a test pipe on my MY07 track car. No CEL for me on my stock ECU. So it should work just fine with your HFC.

This orientation was recommended by Billman.

 

Than you sir! So the Walmart one you linked is straight plug and play? (Simply take off the O2 sensor then screw in the right angle spacer then screw in the O2 sensor into the longer end of the spacer?)

is it ok also for your O2 sensor cables to be twisted up like how it’s shown in your photo when re-installing?

 

Yes, just orient it like I have it and screw it in/tighten it.

The cable is just bunched up because I put it down that way.

Remember what I said about completely unplugging and unclipping the O2 harness from the car.

Take note or mark or take photos of where it clips into.

Then install everything.

Then clip the O2 harness back how you found it and plug it back in.

It should clip to the trans mount, and again to the trans bracket before winding its way above the trans, and clipping once more into a bracket where the plug is.

 

Disabling the secondary o2 will not allow readiness monitors to set. Defouler is the only way, though I've never had to use one on my Berk HFC. I've had the code pending (doesn't throw CEL) but a spirited drive and straight to emissions test when all is showing clear and ready.

 

00-05 models often do not require any CEL fix for a HFC.

But that seems to be dependent on each individual car OR HFC itself.

06+ cars often throw a CEL with anything except the factory catalyst.

Ironically, the HFC modification seems to only be worthwhile on 06+ cars because it reportedly allows one to lower the VTEC actuation and tune for more low end/midrange power.

For 00-05 cars, the only rational benefit I can see from a HFC is that its a cheap fix if your OEM cat fails.