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Engine cutting off intermittently


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I have a 2017 Mack MRU 613 with an MP7 engine (concrete pump truck).  The engine intermittently is cutting off.  Some days as often as 10-20 times.  Other days (like today), it did not cut off once.  Completely unpredictable.  When it cuts off, the dash remains illuminated (fuel gauge shows level, coolant temp gauge registers temp, etc.).  However the DEF tank registers zero empty even though the def tank is full.  Whatever the cause is, whenever it occurs the def level sensor is somehow not 

When it cuts off while in motion, it restarts after coasting briefly.  After restart, def tank registers correctly.

When in PTO, most of the time it can be restarted without delay from the ignition switch.  Occasionally it won't start immediately.  Due to the erroneous def tank reading, my operator/driver has been wiggling the def tank wiring harness when it won't immediately restart.  Not sure if this is helping or not, or simply allowing enough time to elapse for a circuit breaker or an ecu to reset, but he can typically get it started within a minute or two of it cutting off.    After restart, def tank registers correctly in this case too.  

I ran the truck myself all day today so that I could try and diagnose the issue when it cut off, but it did not cut off once.  I tried wiggling the wiring harness on the def tank to reproduce what my operator believes is a loose connection.  I could not recreate the cut off.  I disconnected all of the connectors and checked them for contamination, but all were clean and dry with pins intact.  I put the truck on J-pro and disconnected the def line heaters (the wires my operator wiggles) and other than a open circuit fault, there was no consequence or cutoff.  I disconnected the level sensor, and the def tank registered empty, but the truck kept running.  These findings make me suspect that there is not loose wire or bad connection, but ... hard to be sure.

I located the ACM (mounted on the opposite of the truck next to the battery box) as I have seen other posts suggesting a wire from the battery to the ACM can be the culprit.  Those posts were pertaining to older model Macks than mine, so not sure if this would apply to my 2017, but gave it a look.   I could not find a wire going directly from the battery to the ACM.  The ACM had only one connector, which was under a cover, clean and dry, and looked just like the ECU connectors on the engine block. 

Not sure what the cause is, maybe the ACM itself (do they intermittently mis-behave?).  Been focusing on the def system due to the erroneous gauge reading right after it shuts off, but could be something else I suppose.  

Appreciate any insight anyone may have on this issue.  

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