Is there any way to know without a code reader which codes are active and which are stored? In other words when I do the key off-key on method and see codes on the odometer is there anything that distinguishes stored vs active?

My truck set the CEL on Saturday and the two codes were P2000 and P0513. I assumed the worst that the P2000 was a big deal and I could probably ignore the P0513. The dealer said the P2000 was a stored code and they didn't investigate further. They cleared the codes and said I was good to go. If it happens again I'd like to know which are the genuine active codes.

 

haha, dealer did same thing to me. 50 miles later, CEL came on, then off, then on again 70 miles later. OMG going back to dealer friday, will let u know what they do. p0513 and p245a were my codes. NO CEL currently ever holding ground. just a flash for a few starts

 

P245A is an EGR valve fault code and will be cleared up with the AU flash unless its carboned up.
P2000 - I threw it Friday with P061A (Exhaust Brake Switch Failure) - P2000 is an NOx trap below threshold code. If you run Bio diesel it can put the NOx readings below normal and throw the code.

I threw it right after fueling Friday and refueled today. 15 miles after fueling code went away, so did CEL

Stored codes do not show with the key on/off - only active codes