Check engine light comes on and code reads catalyst efficiency below threshold clear code and Check engine light comes back on after some time. What is the remedy to get threshold above catalyst efficiency to keep Check engine light off permanately.
Check Engine Light on 2003 Toyota Corolla
by Visitor in New Windsor, NY on September 10, 2010
ANSWER by devilscap4 , September 10, 2010
the catalytic converter will most likely need to be replaced, although, a faulty oxygen sensor can sometimes give false catalytic converter codes.