2012 Throwing P21B3 and P0606 code

[Txhazmat]

Hi All,
I have a 2012 2500, 87k miles, no mods. I bought it used in Feb of this year with 69K miles. I drive about 35 highway mile to work each day. After buying it, it threw codes to clean the EGR. The dealer cleaned it 3 months ago. Since then, the MIL light has come on 3 times, then go out a couple days later each time. This Saturday, the MIL light came on again, and threw the P21B3 and P0606 codes. Any thought or suggestions? I live in an emissions county on CO, so can't do a delete.

Thanks!

 

[Jared Herzog]

Did the dealer clean the egr valve and cooler? Replace the ccv filter? I do not know what those codes stand for but my brothers 12 was a soot building beast and required some extra TLC to keep it all working.