Spn 5491 fm14 code

[sun47me1208]

We are on my way to have this code checked and repaired at Fink & Son Diesel Garage in Grayling, MI. We live 122 miles away. When I started the MH the Checked Engine! light (with Exclamation mark) and DEF Level Low started to Flash on my DASH (Driver Info; Cluster). I turned off the MH and filled the DEF tank ( DEF tank gauge show > 3/4 full). It almost took 2 gallons of DEF. Restarted MH, and Check Engine message, DEF Level Low including MILs light for the code above still showed. Drove MH and approx 1 mile from home when the Check Engine Light and DEF Low Level snuff out and only the MIL light was showing. Has anyone experienced this? I mean the check engine and DEF low level



My Code reader say that MIL is SPN 5491 After treatment 1 Diesel Exhaust Fluid Line Heater Relay FM14 Voltage below normal or shorted to lower voltage
Garage has not told me anything yet of what they found.

Is this related to the Check Engine; DEF Low Level messages?


Sun47me1208
2014 Fleetwood Excursion 33D

2019 GMC Canyon
2015 Chev Volt

[sun47me1208]

Update on this issue:


The Fink garage have found the cause of the SPN 5491 After treatment 1 Diesel Exhaust Fluid Line Heater Relay FM14 Voltage below normal or shorted to lower voltage: it was a broken wire (high side of the relay wire), behind the chassis battery. The insulation of the wires became brittle and the wires were corroded that it broke off. My suspect is that the Battery acid got spilled in there and made the insulation brittle and corroded the wire.


I also talked to Cummins about these issue and they say it is possible that the Check Engine light and low DEF when I started the vehicle are related. One thing I learned from Cummins is not to drive the MH when the low DEF light comes on. I was told that I can get stranded on the side of the road.


Fink Garage had verified that the ECM DEF reading is same as the DEF gauge reading