p0420 code prius

 Catalyst Efficiency Below Threshold Bank 1 for the Toyota Prius

Code P0420 2007 Possible Causes for the Toyota Prius Faulty Three-way Bank 1 of the catalyst converters Intake Air Leaks in the Exhaust Tube defective oxygen (O2) Sensor Faulty engine injector (s) Leaking injector of fuel (s) defective spark plugs insufficient ignition timing Engine Control Module issue (ECM) Unclean Air Filter

How Do I Fix the 2007 Toyota Prius's Error Code P0420? Look at the “Possible Causes” section above. Assess the connectors and accompanying wiring harness visually. Look for broken, bent, pushed-out, or corroded connector pins, as well as any other damaged components.