ISB6.7 DEF HELP

[Coronado126]

I'm not completely familiar with Freightliner's, but it should still be the same Bosch DEF system everyone else is using, and the pressure sensor is part of the doser pump.

The doser valve should just be a 2 pin connector used to open and close the valve, along with it's supply line and two coolant lines.

In my experience, all the doser fail to prime and low pressure codes end up relating to the pump assembly. I've had two trucks in my time get diesel into the DEF tank and had very similar issues until all parts were replaced and lines/tank flushed.

INSITE/QuickServe have very good guides on troubleshooting the system when you enter the codes being given by the ECM. Some require graduated beakers to check nozzle and pump flow.

Also if you don't have a QuickServe account yet, you can get a free one from Cummins by just registering as an Limited Owner.