I have an 2007 Classic d-max with 23,000 miles. Check engine light came on and dealer said code P0403 and P046c indicated in ECM. Dealer reprogramed ECM and did a EGR motor cleaning per bullitin DOC-2176732. A few days later the check engine light came on again and back to the dealer I went. This time dealer said the Banks exhaust and Airaid filter were the cause of ECM codes (which were the same codes as before) and basically they could not fix it becuase of the after market parts. Dealer went on to say that mechanic would need to call tech support and when told about the after market parts, GM would put my VIN on the "black list" and my 100,000 power train warranty would be void. Anyone have any suggestions.