rxroth
New Member
I posted this in the Cummins forum, but figured I'd post here too to give FYI to 2018 6.7 Cummins 2500/3500 owners and to hopefully get someone from RAM or Cummins to respond to questions/issues.
Have 2018 RAM 3500 with 6.7 Cummins. Leaving on a 2200 mile trip pulling a 5th wheel, and got the dreaded 'Service Def System See Dealer' message. Message went away after a few seconds, but after researching was worried the remainder of the trip we would get the '5 MPH Max Speed in 150 miles' message. Did not get a check engine light. Stopped at a RAM Service center to read error codes in the pickup and there were none. Made the trip, and made it back to Denver without further incident. Took it to a RAM Service center to check if the pickup had all the system updates, and sure enough it did not. They updated the pickup computer with TSB 18-080-22, dated April 12, 2022. Not sure if having this TSB installed would have prevented us from getting the Service Def System message, but very possibly as it had updates for NOx, SCR, Particulate Matter sensor false fault improvement, among other things. This TSB is for 2018 RAM 2500 and 3500 pickups.
For future reference, if a person does get the '5 MPH Max Speed in 150 miles' message, the owners manual says after the mileage counts down from 150 to 0, you won't get put into 5 MPH mode until you either 1) shut off the pickup and restart, 2) Idle the pickup for an extended period of time approx one hour, or 3) system detects the level of fuel in tank has increased. Talking to a RAM Service tech during our trip he implied that if you had a low fuel light and refilled - it would put you into 5 MPH mode, but if you did not have a low fuel light you could fill the tank and not go into 5 MPH mode. Which would mean, you could make a mad dash to a city with a RAM Service center by filling up fuel tank a few times maybe, and just remember to not turn off the pickup when doing it. Anyone from RAM or Cummins monitor this forum who could answer this definitively? Or has anyone had the mileage count down from 150 to 0, and filled their fuel tank (without turning off pickup) and did not go into 5 MPH mode? We are often traveling Wyoming, Nebraska, South Dakota, North Dakota roads a long way from any town, especially any town with a RAM Dealer, so knowing this would be helpful.
This 150 mile limit is CRAP! Earlier we took the camper on a 5300 mile trip to the east coast. Make the limit 5000 miles, or until next emissions test. Plus, after talking to several RAM Service shops, the fix is not a quick fix, and these places are all a week or more out. Engine runs fine, transmission is good, but some anti-pollution system is going to bring you to your knees and stop you from completing your trip? RAM or Cummins, use your muscle to wake up the people in DC and get this changed!! I've lost confidence in this pickup.
Have 2018 RAM 3500 with 6.7 Cummins. Leaving on a 2200 mile trip pulling a 5th wheel, and got the dreaded 'Service Def System See Dealer' message. Message went away after a few seconds, but after researching was worried the remainder of the trip we would get the '5 MPH Max Speed in 150 miles' message. Did not get a check engine light. Stopped at a RAM Service center to read error codes in the pickup and there were none. Made the trip, and made it back to Denver without further incident. Took it to a RAM Service center to check if the pickup had all the system updates, and sure enough it did not. They updated the pickup computer with TSB 18-080-22, dated April 12, 2022. Not sure if having this TSB installed would have prevented us from getting the Service Def System message, but very possibly as it had updates for NOx, SCR, Particulate Matter sensor false fault improvement, among other things. This TSB is for 2018 RAM 2500 and 3500 pickups.
For future reference, if a person does get the '5 MPH Max Speed in 150 miles' message, the owners manual says after the mileage counts down from 150 to 0, you won't get put into 5 MPH mode until you either 1) shut off the pickup and restart, 2) Idle the pickup for an extended period of time approx one hour, or 3) system detects the level of fuel in tank has increased. Talking to a RAM Service tech during our trip he implied that if you had a low fuel light and refilled - it would put you into 5 MPH mode, but if you did not have a low fuel light you could fill the tank and not go into 5 MPH mode. Which would mean, you could make a mad dash to a city with a RAM Service center by filling up fuel tank a few times maybe, and just remember to not turn off the pickup when doing it. Anyone from RAM or Cummins monitor this forum who could answer this definitively? Or has anyone had the mileage count down from 150 to 0, and filled their fuel tank (without turning off pickup) and did not go into 5 MPH mode? We are often traveling Wyoming, Nebraska, South Dakota, North Dakota roads a long way from any town, especially any town with a RAM Dealer, so knowing this would be helpful.
This 150 mile limit is CRAP! Earlier we took the camper on a 5300 mile trip to the east coast. Make the limit 5000 miles, or until next emissions test. Plus, after talking to several RAM Service shops, the fix is not a quick fix, and these places are all a week or more out. Engine runs fine, transmission is good, but some anti-pollution system is going to bring you to your knees and stop you from completing your trip? RAM or Cummins, use your muscle to wake up the people in DC and get this changed!! I've lost confidence in this pickup.
