I went and had my 06 Cobalt checked out because the dreeded check engine light came one and I got the P0420 threshold bank 1 code. My mechanic, who has been a good friend of mine for quite some time, ...
After months of normal driving with no problems, my 2003 Honda Civic EX check engine light came on during a long trip. Got it scanned and it's P0420: Catalyst efficiency below threshold bank 1. They ...