P0420 code and non-fouler trick tip~ Steel Wool - Ford Focus Forum, Ford Focus ST Forum
Ford Focus Forum
HomeContact UsAbout UsGalleryDiscussion ForumsMarketplace

Go Back   Ford Focus Forum, Ford Focus ST Forum > Ford Focus Tech Discussions > General Technical Chat

General Technical Chat This section is for technical discussions relating to general maintenance, electrical issues, engine trouble, and recalls.

Search This Forum | Image Search | Advanced Search    
Ford Focus Tire & Wheels FocusFanatics Merchandise

Thread Tools Display Modes
Old 11-18-2012, 11:54 PM   #1
Focus Rookie
Join Date: May 2004
Fan#: 8140
Location: Ohio, OH
What I Drive: 2 cars!

Posts: 12
Points 188, Level 3
Points: 188, Level: 3 Points: 188, Level: 3 Points: 188, Level: 3
Level Up 76% Completed
Level up: 76% Level up: 76% Level up: 76%
Forum Activity 0%
Activity: 0% Activity: 0% Activity: 0%
FF Reputation: 1 cal50 Good Standing Member
Buy-Sell-Trade Rating: (0)
P0420 code and non-fouler trick tip~ Steel Wool

2004 ZTS with the 2.3 engine. I got the P0420 CEL code recently. Car runs great with no issues at idle or speed. I viewed the rear O2 sensor voltage with my Actron scan tool and the rear voltage was all over the place hence the CEL light. I use two (2) non- foulers to space the rear O2 sensor out of the exhaust flow. I put it back together and cleared the code with my fingers crossed.
No-go. Check engine light came on in a few days. Checked the voltage graph and although not as wild a shift it must be enough to trigger the code.

I ordered a Motorcraft rear sensor from rock-auto with the intention of replacing it. The sensor arrived and it was after I removed the non-foulers and sensor I discovered that the one they sent me would not fit. The plastic plug was keyed differently and it would not plug in. Crap.

While I had it off I decided to do the "steel wool" trick that was mentioned in several forums. I left the O2 sensor screwed into the non-foulers and packed steel wool into the open end (opposite the O2 sensor). I packed it firmly but not excessively. Put the sensor back into the vehicle and cleared the codes.

Its been about a week and no codes have been thrown and non pending in the scan tool / vehicle computer.

If you are going to do the non-fouler trick I would highly suggest packing steel wool into the end the 1st time you have it off. I am returning the O2 sensor to rockauto. This car has 144,000 miles on it and has been trouble free minus the #3 coil pack I just replaced. I also put new struts on it.

My 2003 has 190,000 miles in the 2.0 liter Ztrec with original O2 sensors.

cal50 is offline  
    Reply With Quote

Bookmarks & Social Networks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -5. The time now is 01:24 PM.

Copyright 2002-2014 FocusFanatics.com. All Rights Reserved : Terms of Use : Privacy Policy : Advertise Information

Focus Fanatics Ford Focus Forum offers many fun ways for you to engage with other Ford Focus Owners from across the world. Whether it be about the aftermarket performance modifications, technical how-to's, European tuned suspension or awesome fuel economy similar to the Acura TLX or Fiesta ST. You can find all Ford Focus and Focus ST related information here. Join our Ford Focus discussion forums and chat with local Focus enthusiasts in your area.