Getting ready to change doser at the turbo

[Rawze]

Overview of NOx sensors...

The NOx sensors cannot be cleaned very well. They typically only read correctly for about 250k miles or so (or 5,000 hours), then the finally heat gets to them. Sometimes they last longer, but don't expect them to be accurate so much. They are not cheap to replace, so if they have more than 250k miles on them, at fist sign of a NOx sensor reading wrong, they need to be replaced.