AdBlock Warning

Parts of this website do not function properly with AdBlock enabled on your device. To get the best user experience on our website, please disable Adblock for this website (domain) on your browser.


Sign in to follow this  
Followers 0
MadMalx

Diagnostics on P0420 code

1 post in this topic

The engine management light has been coming on for a while now on my 2003 Focus (1.6 Zetec SE engine), and after a bit of searching the internet I have found this could be either the lambda sensors or the cat. I used my diagnostics software on the car and found that once the engine had gone into 'closed loop', the pre-cat lambda was switching but the post-cat was giving a steady reading. Problem is that after a few days, when the light had come on again, I re-did this test and found both the pre and post cat sensors were switching with a very similar pattern, indicating a failed cat. Am I right in assuming that the cat might be borderline failing hence giving me the different results?

Share this post


Link to post
Share on other sites
 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0