Insite Help exhaust (SCR/DEF) service required

[Mr Hagg]

This is shop talk by cummins:
This fault detects a mechanical malfunction of the DEF dosing valve, or a pin-to-pin short in the DEF dosing valve circuit.

Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and data link communication issues with aftertreatment components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing, or intermittent connections.

Contamination of the DEF can be a possible cause for this fault code

Id be leaning towards the doser valve is the main issue. Now that its not working your nox level it out of wack. It talks about checking relays and fuses they should be on the fire wall. If you open you up an account on cummins quick serve you can put your engine infor and it has a great diag of those codes. but id be looking into code 3568 first...The quick serve account is free and gives you 5 engines to store if needed..