2010 auto honda accord 115k miles. My car gave the code p0420
Catalyst System Efficiency Below Threshold (Bank 1)
hope this helps everyone with this issue.
I have done some research and It can be a bad CAT, bad O2 sensors, clogged injectors, or as simple as a dirty air filter.
How do i check to see if the O2 sensors are the issues if I've already inspected the Air filter?
I do not own a scan tool
Chances are that it is the O2 sensor. Just change that one out and you will know. It is a lot cheaper than a new cat especially if you live in CA.
yea i thought about doing that!
I am wondering which online store is better or am I better off going to a local auto zone or o reillys?
whatever is cheaper try them all, like rockauto.com
see if the local parts store will match prices