What does this mean? Someone please help!
My engine check light came on and it said "Catalyst Threshold Efficiency Low." on 2005 Acura TL
one of your catts is going bad did it say bank1 or 2 and per catt or post catt. it means you o2 sensors are not seeing enough difference between pre o2 and post 02 but u need to figure out if its an 02 issue or catt issue.rec seeing a mech that knows these cars for proper diag