oxygen sensor graph review help. Cat dead? - Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum
Ford Focus Forum
HomeContact UsAbout UsGalleryDiscussion ForumsMarketplace

Go Back   Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS 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    
FocusFanatics Merchandise

Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 02-03-2012, 09:44 AM   #11
Join Date: May 2011
Fan#: 85627
Location: Minneapolis, MN
What I Drive: 2003 CD silver SVT

Posts: 497
FF Reputation: 10 Grinder Great Standing Member
Buy-Sell-Trade Rating: (0)
Both sensors are working properly but yes, the switching downsteam sensor indicates that your cat doesn't have the ability to store oxygen very well. If this where another vehicle I'd say your cat is wasted and should be replaced.

However, from my experience this is quite normal. The cats on the SVT aren't very efficient and the ONLY time I've ever seen a steady downstream signal on one of these was at about 3000rpm down the highway. I'm guessing the VCT system does a good job of controlling NOx so HC and CO are the only post-combustion emissions the cat needs to deal with. Naturally, a well-tuned mild 2.0L isn't going to have very high HC and CO levels so the emissions threashold required to set the P0420 DTC is rather generous. In other words, eventhough the downstream signal switches like crazy, the emissions are low enough that the government doesn't require a code to be set.

But I wouldn't be surprised if your code comes back. Eventhough your signals look like other SVT's, your PCM obviously saw an excessive switchrate so you either had a momentary fuel quality issue or your cat is loosing it's ability to store what little oxygen it's inteded to store...
Grinder is offline  
    Reply With Quote

Bookmarks & Social Networks

Quick Reply

Register Now

In order to be able to post messages on the Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools
Display Modes

Posting Rules
You may post new threads
You may 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 03:47 AM.

Copyright 2002-2014 FocusFanatics.com. All Rights Reserved : 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 Audi S3, Ford Fusion and Acura TLX. 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. Challenger Hellcat - Charger Hellcat