cat. code P0420 - Ford Forums

lutkosmo · 03-03-2008, 15:15

Hey I gotta 2001 P-71 and my engine light was on, Had it checked out and it was a code P0420. Cat. efficiency low, on BANK 1. Does this mean my cat. is plluged on the passenger's side? Bank 1 is on the passengers side right?? Any help would be great.

btexpress · 03-04-2008, 08:10

P0420 indicates the cat is not doing it's job, you may need to replace it.
This has been discussed here before.

This code does not mean replace sensors

Usually happens on high mileage engines. Or a long time misfire or other problem that may have damaged the cat.