Cars and motorcycles How to Check a Catalytic Converter for Blockage or Efficiency Below Threshold Issues – YouTube diy projects ⋅ November 16, 2018Here is a video on how you can diagnose clogging or efficiency below threshold (P0420) issues with your catalytic converter.Bookmark(1)Please login to bookmark Do you have 10 seconds? Show this DIY to your friends and fans. Report Content To report this post you need to login first. Like 0 Thanks! You've already liked this No comments diy projects Web: Leave a Reply Cancel replyYou must be logged in to post a comment.