I have a 2017 Chevrolet Colorado 2.8 turbodiesel that has a message on the display saying poor quality def fluid. I had it to the dealer and they replaced a corroded wiring harness, fluid level sensor and control module and that didn't fix it.
Only other thing I can think of would be bad NOX sensors so should I replace those? I heard that they can get clogged with soot.
It has 163000 miles and its off warranty.
Hey there! Welcome to the show. Awesome little truck by the way; I personally had an order on a diesel Canyon last December before GM cancelled it. If you haven’t seen it, Scotty did a mini review of the 2.8 Duramax a couple years back... worth a watch if you haven’t seen it.
It’s possible, maybe probable, that you’re right about the Nox sensor. Unfortunately that’s an expensive part. It also seems to be backordered nationwide so it might be hard finding one. A few thoughts in the meantime:
If you haven’t already (and the dealer didn’t do it), consider draining and refilling the DEF tank. Labor intensive on most trucks (not sure about the 2.8) but not expensive if you do it yourself. Drive it until the old fluid is purged from the system and see what happens.
You also might take it to a specialized diesel shop; the dealer had a swing-and-a-miss, and since it’s off warranty anyway you might as well take it to somebody who knows what they are doing. (Most dealers only see a handful of 2.8’s, so the techs don’t typically have a lot of experience with them.)
I’d also look at duramaxforum.com . Their archives are fairly comprehensive, and if you don’t see what you are looking for you can cross-post your question there.
Good luck!
