Do you guys think it is due to the corrosive nature of DEF? I noticed the one time I filled a tank, it left a crystally white residue all over. My local shop here in so cal can do a DEF delete but we now have to smog our diesels here in cali.
The white crystalized residue is normal.
Although it's not an approved procedure but is fairly accurate. you can tell if def fluid is tainted by pouring a small amount on the floor and letting it evaporate. if it crystalizes its good. GM has a test tool, but the floor method is accurate.
I could never get a straight answer from TAC (technical assistance) as to what causes the repeated failures that we deal with.
99% of the time it's the tank heater which is part of the pump assembly. I've replaced numerous DEF injectors along with the NOX sensors.
Warranty repairs require long lengthy test procedures for the DEF system. It's a pain in the ass. The repairs are also followed up with a "service regen" to verify the repair is completed. The "service regent" takes anywhere from 30-60 minutes to complete.
I despise working on them. They are dirty and everything is really involved. Most engine repairs require the removal of the cab.
There are many one time use bolts and fuel lines.
Most people that own diesel trucks have no business owning them. They don't drive them long enough or hard enough to get them to do a "regen." they run them out of DEF fluid all the time. There are 10 Def system warning alerts depending on the system, level 7 thru 10 involve speed limitation all the way down to 4mph.
I wouldn't want to own one especially after the warranty runs out. The fuel injectors alone are close to 1K a piece and that doesn't include the labor.
Turbo replacement on the older ones suck because the cab need to come off. The newer ones you can squeak out.
RANT over.