i have a 2003 dodge ram 1500 4x4 5.7. the check engine light has been on for a couple of months, i just pulled the codes i have three.

1) P0420 - from what i can see this is the downstream o2 sensor, am i correct?? it has never been replaced yet.

2) P0581 - Cruise Control Multi-Function Input "A" Circuit High???????

2) P0593 - Cruise Control Multi-Function Input "B" Circuit High???????

my truck does not even have cruise control.

thanks for any help

 

Well I can't help you with the cruise control issues thats weird. By the circuit being high though means to me that something may have been disconnected, like a connector somewhere that disables the cruise control. But that's a guess, besides that how miles on the truck? Downstream o2 could be a Cat converter issue or the o2 sensor is bad. I'd change all of them, if your over 75000 miles.

 

i am having the same code P0420 catylist below efficientcy. i have been trying to fix it for months. i replaced the cat and both oxygen sensor with mopar ones. couldnt even make it 1 mile on aftermarket sensors before the light came on. now with mopar sensors i make it like 30-60 then the light comes on lol. i barely got it to pass inspection.