I do not know what year this started being available on Dodge Rams, and it may be available on other brands and makes as well,but here is a nifty little tool for those who don't already know about it.

If you feel there is something wrong with your vehicle, and it has a digital mileage guage, try turning the key all the way till the cluster lights come on, then off, then on, then off, then on, leaving the key in the on position. The code should read in your mileage area. Or it may read "done", meaning it didn't find an error.

Then again, Autozone will scan it for free if you can get it to them.

 

How'd you find that out?

 

This has been a feature on chrysler/dodge family cars/trucks since christ was born AFAIK.
It works on my '95, but instead of reading out on the OD display the computer flashes the check engine light.
I used to have a '85 LeBaron 2.2 turbo and it would display the fault codes the same way with the power loss light.