My check engine light came on a few days ago and I took it to the dealer, who said there was some carbon buildup in the EGR and there would be no charge. Please excuse my ignorance, but what is EGR and is what the dealer told me correct?

I remember receiving a letter from Honda explaining some kind of warranty extension but do not remember exactly what it was for, was it for this sort of problem or did they extend the bumper to bumper?

Thanks in advance everybody!!!!!!!