why is my check engine light on?
on 2008 Pontiac G6

code p4020, dealership says its one of the catalytic converters, how do I know which one it is. And what is the cost for repair? It just crossed 100,000 K miles, is it worth repairing?

Asked by for the 2008 Pontiac G6
Did you PAY for the diagnosis? IF so the dealer should tell you.