No fault code but cat still red on scan tool

Question

Cannot smog if did not go through cat cycle.

Answer 1

Catalytic monitor when it does not complete the monitor test does not mean you would need a catalytic, in order for the catalytic to complete the ECM needs to see a coast with a downshift, there are certain criteria that each maniufactuer and each different year require a drive criteria. Most emission test would tell you drive at least a hundred miles the reason is somewhere during the drive you are bound to meet the drive criteria.