NEWMAR Complaints

The contact owns a 2019 Newmar Dutch Star Spartan Motor Chassis RV. The contact stated while driving 45 mph, there were several unknown warning lights illuminated. The RV was driven to the dealer to be diagnosed. The contact was informed of the DEF head (Diesel Exhaust Fluid) failure. The dealer was able to clear the error code but stated that the failure recurred, and the engine degraded the speed on the RV. The mechanic recommended that the RV not be driven. The RV was not repaired. The manufacturer was made aware of the failure. The failure mileage was 5,409.

My motorhome is currently in a Freighliner shop to replace the 2nd defective DEF head in less than 19,000 miles since New. The defective DEF head causes a derate of power and total shut down and can leave you stranded on the highway or coming down a mountain pass with no power defeating the air compressor therefore no air brakes with a 45 foot, 58,000 GVW vehicle. In my case I was able to get off the highway before total shutdown only because I was aware of the built in shutdown design of the emissions system.

The Shaw DEF head failed. Started engine and received MIL light - Emissions. Checked codes and saw "SPN 3031 FMI 9-Abnorm. Update Rate" - "Aftertreatment 1 Diesel Exhaust Fluid Tank Temperature". It should be noted that the motorhome was in my enclosed shop, no excessive temperature. It was started in the morning after setting overnight. Knowing that this could potentially derate engine, I contacted Spartan & a local repair facility. Was able to get DEF Head replaced. I am the original owner of the motorhome. Fortunately this happened while preparing for 3-week trip (at home) and not on road.

While staying at a campground in Creede, Colorado my motorhome displayed several fault codes relating to the emissions system. I immediately called Spartan (the chassis manufacturer) to report the faults and they explained my Def Head sensor had failed and that I should try to get to an authorized service center as ASAP. So the following morning I left Creede ( a remote location that is far away from any authorized service provider) in route to Fredrick, Colorado, the closest service provider. I made it to Littleton, Colorado, 25 miles south of Fredrick when the engine derated to around 5 miles per hour. I then had to arrange to have my 45’ motorhome towed the remaining 25 miles. Fortunately for me, the derating happened at a truck stop so I was able to safely maneuver the vehicle to a spot to await the towing company. However, this could have been tremendously hazardous had the derating occurred on the highway, for me, my fellow drivers and the towing company personnel. Now Spartan, the chassis manufacturer that is responsible for the Def Head senor is telling me it may be 3 months until they can provide a replacement part and I should just be patient. Fortunately we have friends in Denver that we are able to stay with for a few weeks while we wait, but we may be forced to rent hotel rooms to wait out the part turn around. We explained to Spartan that we live in Land O Lakes, Florida and are for all intents and purposes we are stranded and are forced to bear great financial burden until Spartan decides to send the service provider the parts. It is also our understanding through communications with fellow RV’rs this same cycle is happening with great frequency putting lives at great risk and financial hardships. I certainly hope you can take action to cause Spartan to action to provide either the parts required to solve this very well known problem with the def head sensor components or at least a temporary fix to enable the vehicles to be driven.

When preparing to leave, my coach received a check engine light, and 3 error codes from the Cumins ECU. SPN 3364, 1761 and 3031. All FMI code 9. My engine is Likely now debated to 5% power and I was just able to return it to the driveway at the house. Thankfully I hadn’t gotten onto the busy interstate when it happened. After contacting Spartan Chassis, they informed me that I needed a new DEF Head unit. This has been a major issue across the industry. The part is manufactured by SHAW and parts are not available. I was told by Spartan “August or September” for parts. I am unable to move the coach for fear that it is in fact debated to 5% so will need to have a mobile mechanic dispatched to replace. I understand the need for emission controls, but to derate the engine because we might have a little bit dirtier tailpipe until its fixed…. Major safety issue as there is NO workaround.

Since purchasing this RV new, I have had the DEF Head fail twice. 1st time was Sep 2019 with a mileage of 14066 and the 2nd time was April 2021 with a mileage of 16018. Both times DEF Header Assemblies were replaced. When these fail the motor can de-rate at any time. Very dangerous when traveling down the highway. Both times the low DEF warning and check engine lights came on.

We got the check engine light on after starting up our coach on July 6. We got several fault codes: SPN 3364 FMI 9, SPN 1761 FMI 9, SPN 3031 FMI 9. The codes indicated that we had a faulty DEF Header and it needed to be replaced. And if we drove the coach at some point it would "derate" to 5 miles an hour and we would not be able to drive it. We were told by the chassis maker (Spartan) that we would likely not be able to get a replacement part until September or October due to the global microchip shortage. And even though there was nothing actually wrong with engine or the DEF (we had a full tank) there was no work around. Because we were in West Yellowstone where there was no diesel engine service nor a place we could leave the coach for several months. We decided to drive the coach to our next destination, Lander Wyoming which had two Cummins engine shops. We made it there, but then got the "stop engine" code - SPN 5246 FMI 16. The coach derated and we could no longer drive it. The Cummins service shop was able to clear the "stop engine" code, so we could drive it. But the check engine codes would remain until the DEF header was replaced. And countdown would restart to "stop engine". On the irv2.com RV blog forum, Spartan chassis owners, with Shaw DEF headers have reported the DEF header failure. A number have had multiple failures. Since it seems as though it may be months before a supply of DEF headers will be readily available and there is nothing fundamentally wrong with the engine, it would be tremendously helpful for Cummins or Spartan to design a workaround while the parts supply is rebuilt and it seems likely that Shaw needs to redesign their DEF Header to reduce the failure rate or Spartan needs to find a new supplier.

The failure has occurred in the emission system. The DEF SENSOR set off 2 Check Engine light warnings on the dash. It did not tell me any other information. I was fortunate to return from my trip without incident. However, after speaking with the chassis manufacturer (Spartan), I was fortunate to be able to continue. Had I gone any further the engine would have begun a shutdown leaving my 24 ton RV stranded roadside. It could have been very serious breakdown on a metro highway causing major traffic jams or left stranded in a remote location. The component required for replacement is not available till late Aug or Sept. As we live full time in the RV we are now stranded unable to travel until the part is available. Although our example appears to be an inconvenience we have dozens of other RVers experiencing this same problem and unaware of being stranded until the failure occurs. Whatever is causing the failure of these DEF sensors, owners should be notified and a general recall for replacement should be issued.

For no reason started getting codes for low D.E.F and then buzzers and finally engine light for engine derate. Called Spartan, which is the chassis manufacture. Was told that the they were having a lot of problems with the DEF head and to leave it in a safe place because replacement parts were not available. Stated it could be 1 to 2 months before a part would be available. I was over 700 miles from home and not very happy about leaving a half million dollar motorhome in the middle of no where. So I drove it with lights and buzzers going of and finally made it home. My understanding is that there are hundreds of cases like mine and don't understand why Spartan has not recalled and fixed this problem.

I recently purchased a 2021 Newmar Dutchstar Motorhome, and took delivery recently. The Diesel Exhaust Fluid (DEF) sensor failed in less than 3,000 miles. As a newbie in the motorhome world, I was stunned and very disappointed that this failure occurred so quickly, and also with the ramifications of the failure. When DEF sensors fail the engine can go into derate state which can cause my coach to move at a maximum of 5 mph in less than a couple hundred miles, and then the engine SHUTS DOWN. I contacted Spartan motors, the manufacturer of my chassis, and was told that this is a known problem with diesel engines, and that there is a worldwide problem with the DEF failures compounded by a worldwide shortage in functioning replacement parts. The DEF sensors regulation was passed by EPA in 2016, stating the DEF concentration be measured in the DEF tanks of vehicles. I believe that Shaw Development is currently at the sixth generation of the DEF sensor which are still failing regularly on brand new 2021 motorhomes. That is six attempts to make a part that continues to leave people on long trips stranded. As a female driving my coach, this is a major problem. First, because I cannot even drive my brand-new coach anywhere but also because the prospect of getting stranded on the side of the road, as a female, is too frightening to risk. And there is no prediction when I will get the part needed to repair the failure, or whether that part will be defective too.