Quote:
Originally Posted by TexasSprinter
Well, both front and back have now been replaced, and at under 13K miles. What's the deal with these? Will they continue to go out? So far, warranty has covered them, but they are pricey to replace and a pain when you are out on a trip and they fail. Also, my DEF consumption seems to have gone WAY up in the last couple thousand miles. Any ideas?
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First the Nox sensors have been upgraded.
Equally the thermal couples which monitor exhaust temperatures have also been changed .
Once this spendy package has been installed it then has to be programmed in.
I can tell you that it still NOT a perfect fix from my perspective!
If your DEF consumption has gone way up then something is amiss. Simply because the new NOx sensors and programming is specified to reduce condensation forming inside the DPF and cracking the ceramic body of the sensors; which of course was the very reason to modify how the system is now expected to work.
I usually see "other related " problems arise after this Nox sensor exercise appear after about 300 miles of use! Hence you DEF consumption comment comes as no surprise!
Frankly the system needs to be checked AGAIN for operation and your DEF consumption observation reported.
For info the DEF injector works at 5000 Hpa of pressure and it is blown into the refectory as a mist.
A simple scan test will first ensure that the injector is working and holding residual pressure. Often affected by DEF crystal deposit the spray can start flooding the system and causing excessive DEF consumption --OR the temperature of the exhaust is going way too high causing excessive Nox output an lack of effective emissions control.
All the best
Dennis
Mechanic
Linear Mode
