trouble code

[np205]

got a 0420 something about the cat?? anybody know what???

 

[firefighter614]

damn I got the same code thursday! they told me it might be clogged. did your engine light come on and off? shitty gas mileage? mine did too.. I wish someone who knew more than us would post a replY!

 

[Twizzler09]

Post up the code definition, not just the number. Surely whoever pulled the codes gave you the real definition and didnt say "its got something to do with the cat".

You could also try looking up the code definition yourself, a simple google search just got me a definition. Catalyst Efficieny Below Threshold.

That code can be triggered by a few things, a cat thats no longer operating properly, an o2 sensor thats quit working, rich running conditions (that arent bad enough to trip a rich code). If you had a shop get the code for you, I highly suggest you go back and tell them to be more thorough and have them run a datastream while the truck is running, that will get you alot of info about the behavior of your truck and it will also show if one or more o2 sensors are functional/non-functional.