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Ford Repair/Ranger P0420 code


I have a 04/11 Ranger with this code on:
P0420 B1 catalyst efficiency below limit.
Where should I start,the truck is running OK but the long term data are stuck to 99%,the short ones are in the 3 to 4 % range.
I have access to the OTC EVO scanner and wiring diagram from Mitchell on internet but I'm not very familiar with these tools yet.
Waiting to hear back from you.

Hi, I hate to be the bearer of bad news. But that code comes on for only one reason . The converter has failed. Unfortunately , tune up filters and so on won't fix this problem. I think if you even google this code with your vehicle , you will receive the same answer. I am as honest as I can be with people so,... Let me know if you get a different opinion and I'll work with you further  

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I can help you to answer most vehicle questions dating from 2000 and on. cars and light trucks relating to ford electrical. air conditioning, heating, brakes, steering and almost all driveabilty concrns. I am well versed in the area of Fords new sync/ford and lincoln my touch systems.


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