I have a 2017 Colorado diesel Lt. It was great for a year. Then the check engine light came on. I took it to the closest dealer (1 Hr drive away). They said it was an EGR code. Drive it and see if it repeats. It was over a week before I needed it, but the next time I drove it the code was back. They replaced the EGR valve.1 1/2 weeks later and the second time I used it steam was coming from under the hood. A hose clamp was not put on straight when the EGR valve was replaced. Next time I used it DEF low. I filled the tank. 150 miles later DEF low again. Back to dealer. They could find nothing wrong. They explained that if there was a problem codes would be set. $82 dollar charge for DEF because DEF fill can not be on warranty. Took truck home. A week later and the next time I go to use it- Low DEF. Back to the dealer! This time they found the problem. When the mechanic replaced the EGR valve he took loose the def hose and did not secure it when he was done. It got against the exhaust and melted a hole in it. Part not available. No reliable truck for over 3 months and down for the hose for a month! I bought a compact tractor 377 miles away and need my truck to go get it! I need the tractor! They gave me a new Silverado loaner, but say I can't take it out of town. I loved the truck till a GM mechanic replaced the EGR valve. Now I am still waiting for a DEF hose to come in to Denny Menholt Chevrolet. Very frustrating for a truck with 14,000 miles on it and I still think it is a great truck. Their mechanic I do not think so highly of.