Skip to content
View in the app

A better way to browse. Learn more.
Ford Owners Club - Ford Forums

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.



Join the Independent Ford Owners' Club

Our community has been built by enthusiasts, for enthusiasts, and proudly run by Ford owners' for over 18 years. As an independent, non-official club, everything you’ll find here, advice, support, and opinions, comes directly from members with genuine Ford ownership experience.

Join our friendly community... it's Free!

 

P0420 Error

Mike 1994
Mike 1994
in Ford Focus Club

Featured Replies

Hi,

A garage apparently changed my cat converter last week because the engine light kept coming on.At were not sitting right and the dash had been popped out.  At first, I thought they'd just took the bulb out the engine light but it still shows up when I turn the ignition on.

However, this morning I scanned the car with my own diagnostic tool and it's showing the P0420 error but no engine light. 

Could he have disabled the engine light from the Cat converter? 

 

Thanks

  • Quote
    • Like 1


    Clear the code and see if it returns. 

  • Quote

    does the cat converter look new:smile:

  • Quote
    • Author

    I've cleared the code yesterday and it had come back on today. Taking it to a garage today so I can check on a ramp.

    I'm not 100% convinced it's been changed

  • Quote

    a P0420 code is quite commonly misconceived as a faulty cat when in actual fact there are several possibilities. 

  • Quote
    • 2 weeks later...

    My engine light stays on and i had both sencors changed twice i cd do with help as well

  • Quote

    • Latest Deals

    Ford UK Shop for genuine Ford parts & accessories

    Disclaimer: As the club is an eBay Partner, The club may be compensated if you make a purchase via the club

    Join the conversation

    You can post now and register later. If you have an account, sign in now to post with your account.
    Note: Your post will require moderator approval before it will be visible.

    Guest
    Reply to this topic...
    Go to topic listing

    The "Digestive"

    • The Digestive Forum Roundup (31st May - 7th June 2026)

      Steve ·
      The Digestive Forum Roundup (31st May - 7th June 2026) We hope you’re all enjoying your week and finding time for some time enjoying your Ford! This week, our vibrant forum has been buzzing with discussions that touch on a diverse range of Ford models, from the Mondeo to the Fiesta and Focus. Here’s a recap of some key conversations that might pique your interest. Starting with the Mondeo, user Frenchspanner shared a particularly frustrating issue relating to a 'Immobiliser Active' message appea
      Steve
      Steve
      • 124 views





    Background Picker
    Customize Layout

    Account

    Navigation

    Search

    Search

    Configure browser push notifications
    Chrome (Android)
    1. Tap the lock icon next to the address bar.
    2. Tap Permissions → Notifications.
    3. Adjust your preference.
    Chrome (Desktop)
    1. Click the padlock icon in the address bar.
    2. Select Site settings.
    3. Find Notifications and adjust your preference.