cummins ISX SCR/DEF service rrquired

Could just be that the def pump's filter is plugged. Could be that the Diesel Oxidation Catalyst is plugged or damaged. Could just be the NOX sensor, etc

 

It could mean many, many things.
Could be a plugged DOC face. Which means there's typically a cause... often, the dosing injector will either leak, dispense too much fuel, or the aftertreatment fuel shutoff valve will #### up.
There could be cracking in the DOC face or the DPF honeycomb. That'll cause problems which will trigger a DTC.
Could be a problem with the aftertreatment differential pressure sensor, which might be a broken wire, a plugged tube, or a bad sensor. If it's not getting to temperature during regens, that could be for a number of reasons. Too much fuel or a restricted airflow (due to blockage in the air intake or a clogged air filter) and cracking in the DPF (on Cummins trucks which use the 90 degree outlets, cracking at the base of the neck is a common problem).
It could be a problem with the DEF doser, the DEF sending unit, the DEF heater line, etc. For the SCR, it could be catalyst conversion efficiency... that DTC can be caused by a faulty nox sensor (and there should be such a code corresponding to it) or poor air intake. If you get a code of "SCR Mechanical Calibration Out of Adjustment" (or something like that.. I don't remember what it is ver batim), you're replacing an SCR. Seen a lot of Cummins SCRs need replacement within the warranty period.
Either way, you're going to need to get hooked up to Insite and have DTCs checked. That message on the dash is a general warning, and, unfortunately, doesn't get as specific as you'd need it to be for you to try troubleshooting it yourself.

 

Is this a fault on your dash? If so, what is the exact fault?

 

One thing witching hour forgot to mention is that it might just be a communication problem between the computers and end up clearing the code all by itself.

 

Hard to say without fault code so much with these systems

 

What year is that engine? Would like to know what the mileage is and engine time is on it too...just curious.

 

You should definitely let us know what the issue was when you get it checked out.