[navybanker]

I posted on the two major Duramax websites but don't think I did on this site. Some of this may help if you find yourself staring at the message "poor quality diesel exhaust fluid" and limp (speed limitations)mode in 99 miles. Later the check engine light came on with the code P2BAD. Dealer had the truck for two weeks and hopefully it is fixed after at least five parts and four regens. I have driven the truck 500 miles with no messages or CELs. I have my fingers crossed! The truck has 63,000 miles and everything was covered under warranty. The first thing the dealers are told to do is question the DEF quality. They may say you should only purchase from GM dealers. I filled with def at Flying J about 300 miles prior to the message. I was told initially that you shouldn't buy at truck stops. I did a lot of research on the web while the truck was being worked on. GM site explaining the emission systems (DPF and DEF) said fluid was available at GM dealers and most major truck stops!? GM site for service departments did say to question customer about the def quality and where it was purchased. This dealer didn't have a tool to test the DEF. This dealer now has one. It is a rather simple test of specific gravity similar to testing battery fluid. The dealer talked with GM techs about my vehicle and tried many things, including replacing two NOx sensors, diesel injector (9th injector) in DPF, DEF injector in exhaust pipe and computer update. They drained the DEF tank and replaced with "GM" DEF. Each time a part was replaced they performed a 'regeneration' which is burning the diesel exhaust "carbon" out of the DPF. They did provide a courtesy auto for my use at no charge. These systems are complicated! My dealer is a small one in a rural/farming area. The mechanic said most people in these parts delete the EGR, DPF and DEF systems which voids your warranties. Engineers feel free to correct any statements above.

I post this as some of you may run into this and it will save some time when taking your vehicle to the dealer! No Duramax bashing as Ford, Ram and diesel motorhomes are reporting this problem also. I don't think this problem is widespread but you need to be aware.