So I just bought a 2010 Ram 1500 with the 4.7 from a dealership. We took the truck on two test drives and it drove perfectly fine with no problems at all. Then today, 3 days later, I was taking my girlfriend home and I get a check engine light. The truck did not run any differently when the light came on. Running on all 8 no loss of power and starts and shifts just fine. I have a scanner coming but am wondering if there are any suggestions on what the problem might be.

 

Did you fuel up? A loose fuel cap can set the light off. Later models read a note, earlier ones just set a code and the light. Until your scanner arrives, do the key dance. Don't bump the starter. Turn the key on, then off, then on, off, then on and leave it on the third time. This tells the computer to go into self test mode. The codes will show up in the odometer.

 

I did not fuel up, but I’ll double check the cap when I leave and do the key test and see what it says.

 

So I got the code back, P0430 Catalyst System Low Efficiency Bank 2, from what I read this is not a big deal. So I’ll likely just ignore the light for now. Thanks all

 

This may be something as simple as old fuel in the tank. I'd add a bottle of fuel system cleaner and fill the tank up. The lower you run the old fuel, the better. It may not clear the code, but it's cheap and you'll need to fuel up anyway. No telling how long that truck sat with that tank of fuel.

 

I’ll throw in a bottle tonight and see if that helps at all.