J&JD
RVF Supporter
- Joined
- Nov 3, 2019
- Messages
- 2,603
- Location
- Fremont, California
- RV Year
- 2017
- RV Make
- Newmar
- RV Model
- Dutch Star 4018
- RV Length
- 40’
- Chassis
- Freightliner
- Engine
- Cummins ISL450
- TOW/TOAD
- Jeep Wrangler Sahara
- Fulltimer
- No
There have been many discussions on other forums concerning being stuck on the highway with a def head failure. If the def system fails the system will begin to derate the engine until the coach will become virtually immobile. This can, obviously, be potentially a very dangerous situation on a narrow busy road.
A temporary solution that might keep the coach running until you can get to a shop to have the codes/system checked is to disconnect the speedometer from the DS (left side) of the Allison transmission when def failure/warnings occur and before derate begins. Apparently this was recommended by truckers that have had the problem. I have no idea if this works. I’m just passing on the suggestion.
Here is a picture of the speedometer connection:
A temporary solution that might keep the coach running until you can get to a shop to have the codes/system checked is to disconnect the speedometer from the DS (left side) of the Allison transmission when def failure/warnings occur and before derate begins. Apparently this was recommended by truckers that have had the problem. I have no idea if this works. I’m just passing on the suggestion.
Here is a picture of the speedometer connection:
