P420 engine code

prienn · Post by **prienn** » 10 Mar 2009, 22:49

On my '01 V70 non-turbo 2.4 125k, the check engine light just came on and registered 'emission service required'. This has turned on, then off a few times.

I had it scanned as P420 - catalyst system efficiency is below threshold bank 1. What does this typically mean for my engine?

Post by **MadeInJapan** » 11 Mar 2009, 04:55

That's typically a front 02 sensor code but for it to come and go like this I would suspect a small vacuum leak somewhere...