DTC P0420: 3-Way Catalyst Function: Notes

NOTE: Using the following diagnostic procedure assumes the presence of a current (hard) DTC or the ability to duplicate the setting of the DTC using described procedures, intermittent recreation procedures or a test drive under conditions stored in freeze frame data. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in TESTS W/CODES - INTRODUCTION article. If DTC cannot be duplicated, proceed to TESTS W/O CODES article for diagnosis by symptom.