DEF Issues

[PapaRed]

Am considering trading up from my '04 CAT powered coach to a 2014 - 2016 model with the Cummins ISB -6.7L engine. Problem is that on another forum I've been reading horror stories concerning limp mode and engine shutdown with DEF system faults. What is your experience with Winnebago products?

Additionally, it seems that there is an ownership issue when it comes to DEF warranty work. Who is responsible? Winnebago? Freightliner? Cummins?
Or maybe Ford or MB?

Would be interested in your experiences with Journeys/Meridians in the 2014-2017 year range.

[Winterbagoal]

Unless the DEF system has been modified in some way by Winnebago, without the permission of the chassis maker (highly unlikely), DEF related problems are the responsibility of the chassis/engine maker. DEF just sounds scary on internet forums. It isn't really, just another thing that the automatic DEF monitoring system (you) takes care of, like everything else on the coach.

[Old Navy]

DEF was a significant problem with the Cummins in RAM trucks. The primary issue was the system would erroneously detect "bad DEF fluid" and start counting down to limp mode. My truck did this once, hundreds of miles from home of course, but cleared itself. Many people were not so lucky and went to their dealers where they were charged hundreds of dollars to drain the DEF tank, reset the code and sometimes replace the sensor.

In the end, there was a recall of 500,000 trucks to delete a sensor and update the SCR system. That seems to have fixed the "bad DEF" problem. Of course the people who already had issues never received refunds.

Just like your fuel tank, allowing your DEF to go all the way to empty is asking for trouble.

FWIW, here in CA, Emmissions Waranties are 7 years/70,000 miles by law. Not sure what they are in AZ.

[Elkman]

It is much like the 1970's when catalytic converters and oxygen sensors were first introduced so engines could burn unleaded gas. With diesel a bad sensor or DEF pump or warming element or simply bad coding by the manufacturer's programmers can casue problems and put the vehicle into limp mode.

My last truck had the first year of GM's new emissions control system that used DEF and I had problems on 4 trips with the engine going into limp mode. What needs to be fully appreciated is that in limp mode the maximum speed is reduced to 55 mph. That makes it very unsafe to drive the vehicle on the road. Good luck merging with big rigs and dumb motorists when the fastest you can accelerate to is 55 mph.

Each time we had problems we had to cancelled the rest of our trip and then it meant several trips to the dealer to get the problems properly diagnosed. Often the error codes were wrong or misleading and I only found one mechanic and one Chevy dealership who was able to troubleshoot the emissions control system. It is why when looking at buying a new Class C motorhome I decided to only buy either one built on the Ram chassis with the new Penstar V-6 gas engine or one built on the Mercedes Sprinter chassis with the Mercedes diesel engine.

None of the U.S. manufacturers of small truck depend on diesel engines for their vans and pickup trucks. And the Cummins engine that goes into a Ram pickup is nothing like the Cummins engines that go in the big rigs. The fleet operators of diesel powered tractors also have full time staff of highly trained mechanics to keep their trucks running. Even then there are many operators who want to have electric or hydrogen fuel powered trucks as the maintenance and repairs are drastically reduced as is the amount of down time when they are not on the road making money for the company and the mechanics do not need the same level of training or skill.

When I bought my diesel pickup I went with the diesel engine to get more power for safer accelleration with a heavy load and to get 30% more range with its 36 gallon fuel tank. Having more range before needing to find a gas station. My truck with a heavy load averaged 13-14 mpg as compared to the same trucks with the gas V-8 engines averaging from 6-9 mpg.

With the Class C motorhomes I looked at the cab chassis were equipped with small 24 gallon fuel tanks and so having the much more fuel efficient diesel engine was an important consideration. It is also not legal (emissions laws) to put a larger gasoline tank in a vehicle even if there is room for one.

[Old Navy]

Originally Posted by Elkman

It is much like the 1970's when catalytic converters and oxygen sensors were first introduced so engines could burn unleaded gas. With diesel a bad sensor or DEF pump or warming element or simply bad coding by the manufacturer's programmers can casue problems and put the vehicle into limp mode.

My last truck had the first year of GM's new emissions control system that used DEF and I had problems on 4 trips with the engine going into limp mode. What needs to be fully appreciated is that in limp mode the maximum speed is reduced to 55 mph. That makes it very unsafe to drive the vehicle on the road. Good luck merging with big rigs and dumb motorists when the fastest you can accelerate to is 55 mph.

The Diesel SCR limp mode is purely an EPA mandated "feature". A failed DEF/SCR system will have no effect how your truck runs, only how much NOx is in the exhaust. So, the EPA insisted that evil diesel engines must basically be taken off the road within 100 miles of a emissions related failure. The warning people got on the dash prior to limp mode was “5 mph Max Speed in 100 mi, Service DEF System, See Dealer.” There was a partial work around, as the limp mode didn't engage unless you shut off the engine. So you could drive further than 100 miles, but once you shut down, you are stuck. We all want clean air, but this goes WAY too far. 100 miles? Can we at least be reasonable? How about 30 days? How about 3,000 miles? If I lived in a state where I could, I would delete the smog systems from my truck. Not because I want dirty air, but because I don't want to be stranded a thousand miles from home, hostage to a mechanic who knows I'm stuck.

Sorry for the rant...

[Elkman]

Asthma from NOx and other engine emissions costs taxpayers billions of dollars with emergency room admissions alone. I have no issues with emissions controls systems only poorly engineered ones as with many American made cars and a number of German ones that had to cheat to pass the emissions tests.

The limp mode is OK in theory if you happen to be in town and there are no freeways and the problem is legitamate. On the other hand there are companies that are allowed to sell emission delete kits that are illegal to install and make the vehicle illegal to operate on the highway. When catalytic converters first came into widespread use on cars in the 1970's many people bought bypass pipe at their local muffler shop until their sale was banned. But the diesel delete kits have been completely ignored in all 50 states.

We are now at the point will all the diesel polluting vehicles that the only real answer is cars and trucks that produce zero emissons. It is not an ideal situation but with all the companies and vehicle owners cheating for profit, it is what needs to happen.

At least with my own investigation the issues affecting reliability are largely with the U.S. auto makers diesel engines. At least for a van or RV there is the alternative of the cab chassis made by Mercedes Benz. There is also a world of difference between diesel trucks and vans that are driven tens of thousands of mile each year and the average RV owner that may put fewer than 5,000 miles on their vehicle the entire time they own it.

[Dives2little]

I have a '16 Itasca Ellipse (ISL9 Cummins) and have had one DEF issue. It was cold weather (20° kind of weather); system showed low DEF. Once the engine came up to temp and the DEF tank warmed up, the faults cleared.

Mostly, DEF is pretty stable, unless it exceeds 70°F, which is where it starts to degrade. You should expect a year of shelf life unless you are contaminated.

[Elkman]

From Peak website: between 12°F and 86°F — DEF has a shelf life of up to two years. If stored in warmer temperatures, shelf life decreases. DEF should not be stored in direct sunlight. Ideal storage is in a cool, dry ventilated place. It can be frozen without reducing its effectiveness.

I only buy the 2.5 gallon jugs of DEF and add it as needed to the 5 gallon tank of the Sprinter. I have not enough miles on our Sprinter but with my Chevy truck the consumption was 1.5 gallons of DEF for every 100 gallons of diesel burned. 100 gallons of diesel was burned on average after 1300 miles so a gallon of DEF for roughly every 900 miles driven.