P0420 Trouble Code
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Joined: Dec 2001
Posts: 22,436
Likes: 17
From: Louisville,Ky.
It usually means that a cat is not properly working any more.
You can try swapping the rear O2 sensors from one side to the other and see if the problem switches banks. If it does, then a bad O2 sensor is probably the problem. If you swap sensors and the light comes back with the same code, then the cat is probably not working as it should. You must reset the PCM to clear the codes before restarting after the swap.
You can try swapping the rear O2 sensors from one side to the other and see if the problem switches banks. If it does, then a bad O2 sensor is probably the problem. If you swap sensors and the light comes back with the same code, then the cat is probably not working as it should. You must reset the PCM to clear the codes before restarting after the swap.
Senior User
Joined: Jan 2005
Posts: 124
Likes: 0
From: Kabetogama, MN
I have the same problem. Does this problem with the Cats and/or O2 Cat sensors Sensors turning on the CEL light at all cause engine preformance problems or damage if gone unchecked ( meaning if the sensors are getting poor readings, is it sending a single to my truck to preform differently), Or is it just more pollution from my truck and no real concern? I have not had time to change sensors and it is too expensive to change Cats. I was just hoping to be reasured.
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ckellis89
2004 - 2008 F150
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Apr 5, 2016 06:16 PM
