2008 Ford F150 P0420 code
This light has been on for a while now. I have tried two bottles of "CataClean" and no luck. My next step would be to replace the O2 sensors (all 4). My question is the following: Has anyone on here experience this same issue and had the problem fixed by simply replacing the O2 sensors or am I going to ultimately have to buy the Catalytic converter assembly? Also, which side is Bank 1?
Thank You!!
Thank You!!
Last edited by RicanRaskul; Mar 22, 2015 at 09:25 AM.
Thanks for the reply 'LaMartian" and "jamie930"! A little more specifics, Its a 2008 Ford F150 Limited Crew Cab with 87k miles. Which O2 sensor is the upstream one? Is it the one towards the front of the truck or the one after the Cat towards the rear of the truck? What could have cause the Cat to burn up?.....the vehicle runs great with no issues just an annoying Check Engine Light......
A little more specifics, Its a 2008 Ford F150 Limited Crew Cab with 87k miles. Which O2 sensor is the upstream one? Is it the one towards the front of the truck or the one after the Cat towards the rear of the truck? What could have cause the Cat to burn up? The vehicle runs great with no issues just an annoying Check Engine Light.
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Upstream sensors are between the engine and the cat. Downstream sensors are post-cat.
So what can cause a cat to fail, oh... a bunch of things. But the one I would check on a truck of yours' age are the injectors, plugs, and compression. Raw gasoline can destroy a cat easily, so an injector that's stuck open, a cylinder / spark plug that's not burning all of the fuel, or valves not functioning properly can all let raw gas get to the cat. The fact that you didn't get a CEL saying misfire or injector stuck open makes me wonder about valve problems or worn piston rings. You should probably do a compression test on all the cylinders.
So what can cause a cat to fail, oh... a bunch of things. But the one I would check on a truck of yours' age are the injectors, plugs, and compression. Raw gasoline can destroy a cat easily, so an injector that's stuck open, a cylinder / spark plug that's not burning all of the fuel, or valves not functioning properly can all let raw gas get to the cat. The fact that you didn't get a CEL saying misfire or injector stuck open makes me wonder about valve problems or worn piston rings. You should probably do a compression test on all the cylinders.
Last edited by Martian; Mar 22, 2015 at 01:31 PM.










