My van's check engine light is on. I got the code read and it shows a p0420. I checked the book and it says it is Catalyst System Efficiency Below Threshold (Bank 1). The van idles fine, when I go up hills (in Colorado) it feels like it lacks power. Do you think it is an O2 sensor, or is it the catalytic converter? What is a way that a layman like myself can tell?
Friday, April 12th, 2013 AT 11:22 PM