Have a 2000 dodge dakota, check engine light popped on a week ago. No real symptoms other than some idling issues at stoplights & startup (going anywhere from 500 to 1000 rpm); which I attributed to the previous owner letting it sit for a while before I bought it. The codes I got were P1491, P0420, & P0171. No idea what would set off this combination of check engine lights.

 

It looks like you may have a cat going but it is a weird combination. What engine do you have?

If it's a 4.7, check your power steering pressure switch for leaks and fluid in the PCM connectors.

Does the radiator fan work (P1491)?

 

1491 is for elec fan relay
0420 is for catalytic converter
0171 is for a lean fuel mixture
Could have a cat that is getting some build up if it is running good than it may be just starting to go bad.If you are having idle issue could account for lean code. Check IAC. maybe try and remove it and clean the plunger. Also check the TPS

 

I have a 4.7 engine, I'll have to get under the hood tomorrow and take a look at things. Two sons and a wedding in 3 months doesn't leave much time to tinker around with the truck. Any way to tell how a catalytic converter is going bad?