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hammy · 11-25-2011, 12:06 PM

Hi all....I have a 2009 Holiday Rambler with a 425 Cummins..My problem is comm failure between eng and trans which causes shifting problems...
I first get the ABS light on my dash display,ATC, ck trans,ck eng,all gages
going crazy, and then the display"engine comm failure...The manufacter
tells me it's probably the 1939 backbone harness bad connection problem.
Three trips to the specialist at my expense without any correction of this
problem...They can't find the issue!!!!!!!!!
Has anyone experienced this??????????
11/25/11

Thanks....Hammy

Our Time · 11-25-2011, 02:30 PM

Had the same problem, lights on etc, and it would put the engine in safe mode, or not shift. Turned out to be the engine control module (ECM). They couldn't find the problem until one day it just refused to go. Good luck!
Welcome to the forum.

moisheh · 11-25-2011, 02:41 PM

Hammy:
I have had that problem twice. When I called Monaco they told me it is a known problem. Failure of the engine computer to communicate with the Monaco computer. There is a connector on the right hand side beside the frame rail . Between the area above the DPF and the tag. Near impossible to find. There are a bunch of bundled wires and one of them will have a connector covered with tape. I undid it and sprayed the connection with contact clnr. So far so good. Call Monaco and maybe they will give you a better explanation. My neck still hurts from getting into that area!

desertdwelle · 11-25-2011, 03:29 PM

Hey Hammy how often does this happen? It's possible the 1939 is having problems but you should be getting fault codes in the engine ECM the trans TCU and or the ABS ECU for 1939 communication errors. Did the repair facility tell you there were fault codes present either active or inactive? In order for the 1939 to work properly the harness needs to have 60 ohms of resistance (with the key off) and proper voltage with the key on. that voltage should be 2.5 to 3 volts on the high can (yellow wire) and 2.0 to 2.5 volts on the low can (green wire). I know of a couple repair facilities here in the Southwest that are good with this type of problem. But with that said when it comes to finding those types of problems duplicating them is half the battle. Hope this helps,