Wednesday, September 22, 2021
Wednesday, September 22, 2021

RVers stranded with bad DEF sensors. What does this mean? Are you affected?

By Russ and Tiña De Maris
We’ve written several times about DEF (diesel exhaust fluid) sensors that have left RVers and other users stranded. We’ve seen there’s still a bit of confusion as to just what this all means, and what can be done. We thought we’d recap and simplify the situation. And we also wanted to share with you real stories, from real RVers, to illustrate the human toll of DEF sensors gone bad.

First the facts

What’s the background?

Most current USA-produced diesel engines are equipped with federal government-required devices that reduce nitrogen oxide tailpipe emissions.

So what does that have to do with anything?

A major way these emissions are controlled is by injecting DEF into exhaust gases. The DEF helps convert nitrogen oxide, an air pollutant, into nitrogen and oxygen. Both of these elements are found in the air we breathe and, in themselves, are harmless. A monitoring system ensures this process goes as planned.

How does the DEF monitor work?

kus-usa.com

To ensure the DEF in a vehicle system is effective, a monitoring system checks, among other things, its quality, quantity, and temperature. The complete monitoring system is made up of various parts and is commonly called a “DEF head.” If this system determines the DEF isn’t up to standard (or has run out), the DEF head sends a signal to the engine computer warning of the trouble.

The engine control computer, on receiving this signal, turns on a dash warning light. At this point, a sort of “clock” begins a countdown. For many users, after 100 miles or so the engine is “de-rated,” or slowed down to as low as five miles per hour. It’s a sure inducement to get the rig to a repair shop.

So why is de-rating a problem?

If your motorhome or truck is de-rated, you get nowhere fast. If your de-rate happens while traveling down a high-speed roadway, the chances of a rear-end collision from a faster rig are increased. Enter the human toll, not just from a real traffic accident, but the mental stress of worrying about it.

Why not just get the problem fixed and keep on going?

Like so many modern products, DEF heads contain silicon chip microprocessors. These are the culprits that are causing the problem – they’re failing. The chips are very specific in design, and require the appropriate replacements. But just as the auto industry is shutting down production lines due to the worldwide shortage of microchips, DEF head manufacturers are likewise plagued. Many RVers are being told replacement DEF heads could be months away. Meanwhile, their RVs sit immobile and useless. The human toll here is real.

If there aren’t microchips to fix the problem, can’t something else be done?

A temporary “fix” exists. While the EPA (Environmental Protection Agency) requires the DEF monitoring system, it recognizes some “essential” services can’t be stopped. For example, emergency vehicles simply can’t be de-rated, lest those rigs be put out of service. An allowance has been made to keep the DEF monitoring systems in place. They warn of bad DEF, but don’t de-rate the engines. If the EPA were to allow reprogramming of engine control computers in RVs in this same way, RVers could get on down the road.

Wouldn’t that cause air pollution?

amazon.com

It shouldn’t. The problem seems to be not bad DEF but, rather, an incorrect reporting of a DEF situation due to malfunctioning monitors. If the EPA were to allow this reprogramming, even if bad DEF were present, there’s a backup system to stop the problem. These diesel rigs are also equipped with nitrogen oxide sensors. If the DEF system were truly NOT working, and the rig began to produce harmful levels of pollutants, these other sensors would catch it. From there, the engine control computer is alerted, and warnings (and de-rates) would kick in. This would also stop any “enterprising” RVers from simply pouring water into their DEF tank, instead of purchasing and using legitimate DEF.

So why won’t the EPA allow the reprogramming?

The EPA says it’s working with “industry” to explore “all options.” A major player is Cummins, one of the leading engine manufacturers for the RV industry. While Cummins does NOT manufacture the DEF heads used in motorhomes, it does CONTROL the software that de-rates their engines. To that end, Cummins and the EPA must come to terms. This is the reason we’ve encouraged concerned readers to contact both the EPA and Cummins.

Wouldn’t this create an expensive problem for Cummins?

We’re told by industry tech folks that the actual rewriting of the computer code to do this would take minutes. From there, the new code could be transmitted to dealers via the Internet. Once the dealer has the new code, it’s only a matter of having a technician plug a tool into each affected RV and push a few buttons. It’s understandable that the dealer would need to charge some sort of fee for the work, but given the time involved, it shouldn’t be excessive. A bit of effort on the part of EPA, Cummins, and local dealers would go a long way to alleviating the human toll.

Some human experiences

We’ve heard from plenty of RVers who’ve been affected by the “DEF head debacle.” We’d like to share just a few of their experiences.

Robert R.’s trip cancelled
Robert R. recently bought a 2021 Tiffin Allegro bus. With just 4,000 miles on the odometer, his DEF gauge began “reading incorrectly.” Tiffin told the repair shop they’d be happy to send a new DEF head – but they couldn’t give any time frame as to when that might happen. Robert’s cross-country trip plans evaporated. “We can’t trust we can make it, so we cancelled,” says Robert. “Who wants to leave for a trip knowing you could be stranded at any moment?”

Stranded Phillip
Stranded at any moment? That worry materialized for Phillip G. in another “human toll” story. Phillip’s Dodge Ram pickup is his truck of choice for towing his fifth wheel. Out in Michigan, that dreaded dash light came on, and the countdown to de-rate began. Phillip dropped the fifth wheel in Mackinaw City and soloed the pickup into Cheboygan, 15 miles away. The dealer found a stored code, but on test driving it, everything appeared good.

Phillip hitched up, but less than 200 miles later, the dash light came back. This time, an Iron Mountain, Michigan, dealer said a new DEF pump was needed … if Phillip could wait three months for parts. That was a non-starter, so the dealer reset his computer, telling Phillip he could probably go 500 or 600 miles to search for a dealer with the part. He found one, in that 500-mile range, and started out. Sadly, that “500 or 600 miles” turned out to be only 200 miles. Another dealer reset the system again. Again, the count began, and on arrival at a third dealership, he was told that the system couldn’t be reset.

Phillip was stranded with 200 miles to go to get to the part he needed. He couldn’t find someone to tow his fiver to a campground, so he parked the rig at a park-and-ride lot. There the family took the cold stuff out of their refrigerator and spent the night in a hotel, as it was too hot to stay in the fifth wheel.

“The following morning I was able to sweet talk the Sauk City dealer into selling me the part without doing the install,” he reports. He was able to secure another vehicle and drove 380 miles round-trip to pick up the part and get it in the hands of the local dealer, who finally fixed his truck. He sums up his human toll this way: “Needless to say, this experience was very stressful and has made me a lot less comfortable about being on the road, especially far from towns.”

More than an intellectual exercise for Joe G.
The situation could be counted as an intellectual one, as in dollars and cents, like Joe G. experienced. His Ram pickup DEF head issue really cost him. The first dealer who got his part charged him $1,965 while the “list price” showed $1,450. “A wonderful profit opportunity for the Chrysler dealer!” says Joe. But that pump died just days later, and Joe got credit on it toward the next one. “The whole affair,” reports Joe, “cost only $2,907. This includes five days of car rental. What a deal! For less than $3,000 and one stressful week, we helped save the environment!”

But human toll costs more than just money, especially for Alexander G.
Alexander G. had a “dream vacation” in the works. But just weeks before departure, his RV rang up a “low DEF code” warning. He quickly learned there was a line of trucks at his dealership, all waiting for the same part. It seems the DEF head was on “national back order.” “I went through all the stages of grief,” Alexander reports. “Grief with the situation – denial, anger, bargaining, depression, and finally acceptance.” In addition to the grieving, Alexander lost money, but mourns even more the loss of what might have been. “My daughter is now a senior in high school and will be going to college next summer. This means that this opportunity might never happen again.”

* * *

We have no idea how many RVers are either stranded, or have been, while waiting for repair parts. We have plenty of other stories of RVers who haven’t been physically stranded, but their own human toll comes from the fear of even putting the transmission in DRIVE. They’re very much afraid that they’ll get stuck somewhere, far from home, when that dash warning light comes on.

This has to stop.

Related

Will a DEF head problem ruin your trip?
Stranded motorhomes. Is Cummins to blame?
Still stuck with DEF sensor issues? Email Cummins and the EPA
Wikipedia: Diesel exhaust fluid

##RVT1014b

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Irl Sell
23 days ago

It is not limited to Cummins engines, or even the DEF monitoring system. Just recently my 2015 Duramax LML driver info display, without any prior warning something was wrong, told me the DPF needed to be cleaned and to “keep driving”. Not to worry, I should just keep driving until it resolves…. Not! About a minute later the vehicle went into low power mode and since we were in the middle of nowhere the Utah desert on interstate 70 on an uphill pulling a 5th wheel, we had no where to get off the road. We limped up hill at 5mph on the shoulder with flashers on until we could find a safe place to get off the highway. To make matters worse, our right rear truck tire picked up a nail while driving on the shoulder resulting in a flat that had to be changed in 100° temps. This is a very dangerous situation that could have resulted in catastrophe. There should have been some way to override the forced low power mode to at least allow us to get down the road to the next town.

Jerry Odom
30 days ago

“The EPA says it’s working with “industry” to explore “all options.”” Sounds like they are sitting on their hands as usual hopeing it will all go away.

Wayne
30 days ago

So I too am a felon. I once pulled a fifth and got 5 to 8 MPG! Now we pull a trailer 3 times heavier with deleted 6.7 and get 17 (imperial) MPG!
We need some CEO’s and politicians that can say “I know you can, but don’t”.
With my using far LESS fuel I’m doing my part.

Wayne
30 days ago

“Sources of Nitrogen Oxides
Scientists estimate that nature produces between 20 and 90 million tons of nitrogen oxides on Earth each year. Natural sources include volcanoes, oceans, biological decay, and lightning strikes. Human activities add another 24 million tons of nitrogen oxides to our atmosphere annually.”….

“Uses of Nitrogen Oxides
Although nitrogen oxides have gained dubious distinction as pollutants, they are also used beneficially in some industrial processes. Nitric oxide is manufactured on a large scale, and is subsequently used to make nitric acid (HNO3). To create nitric oxide for industrial uses, chemists combine ammonia (NH3) with oxygen (O2), releasing water (H2O) as a byproduct. Nitrogen compounds derived from nitric acid are used to create chemical fertilizers, explosives, and other useful substances.

Charles Yaker
30 days ago

With regard to “this has to stop” you might want to listen to the following Podcast of Macro N Cheese . It’s about infrastructure and includes Chip making here in the USA . the relevant piece comes around the 1 hour mark so you can skip to it if you wish. https://podcasts.apple.com/us/podcast/macro-n-cheese/id1453085489?i=1000532664017

StudentB
30 days ago

I am considering buying a class C rv with either a Sprinter chassis 3.0L diesel engine or a 3.2L I5 Ford diesel engine. Does anyone know if these engines are also plagued with DEF microchip shortage problems?

Jayalanby
30 days ago

Dealers are backed up by a month or more. The last thing they want ior can handle is a software upgrade.

John Green
30 days ago

Makes me so glad that I have a 2011 Dodge RAM/Cummins 6.7L engine that doesn’t use DEF. I now have 125K miles on it towing my Airstream with no problems except replacing an O2 sensor a year ago. First engine part failure in 10 years!!

Gene Bjerke
30 days ago

I am so glad my motorhome is on a 2008 MB chassis. No duals, no DEF, cheaper and easier all around. I’ll do my best to keep the old rig running as long as I can.

Jesse Crouse
30 days ago

All the parties- manufacturers ,dealers, chip manufacturers, engine manufacturers ,EPA, Politicians, and buyers of diesel vehicles should be locked in a room with no water, food or bathrooms till a common sense fix is found. If no units are being sold- no money going to the bonus babies, no taxes going to political authorities and phones ringing off the hook in DC. a fix will be found!!!!!!!!!!!!!!

Bill
30 days ago

This “DEF HEAD” issue is a disheartening event, but keep in mind that a very high percentage of owners have not, and will not encounter it. Without adding that kind of balance to this article, it stokes those fears you mention.
As an example, the CEO of NIRVC did a search across all of their dealers and they only ordered 64 DEF heads over the past 18 months – 1 for a Freightliner chassis, the rest for Spartan. I feel bad for those 64 owners, and certainly hope I never become part of that statistic, but it’s a small group.

There are a lot of mechanical/electronic failures that can disable an engine, not to mention other issues like the severe lack of availability of tires in certain sizes that I ran into.

Dennis
30 days ago
Reply to  Bill

i would like to see that study. where did he publish it? Exactly how many dealers did he actually contact?

Keith B
30 days ago
Reply to  Bill

Brett said that over a month ago. Since then on IRV2 alone there have been 2-3 per week.

David Telenko
30 days ago

I’m wondering why now is the DEF head causing such a problem? I believe its been around about 10 years! What the heck has changed to effect so many vehicles, especially motor homes with Cummins motors? I have a 2017 Forest River motor home with a 6.7 Cummins in it. We are heading to a long a waited trip to Yellowstone. I was told to drain my DEF tank & I did & poured in new DEF, as my m/h has only been driven a few miles in the past 2 years due to covid! Depending on a lot of things that could cause a de-rating to kick in, 2-3 year old DEF, maybe it got too hot.The concern over this has really put a lot of stress on me.
Snoopy

Keith B
30 days ago
Reply to  David Telenko

Everybody is wondering the same thing and so far nobody has figured it out yet.

Lynn W
30 days ago

Another thought….if you bypass the DEF warnings and there is a real problem, you will ruin the engine when the DPF filter clogs up. I really think that RV’ers, in the big picture, are not contributing to any environmental problems with their medium and light duty diesel engines and they should be exempt from these draconian regulations.

Keith B
30 days ago
Reply to  Lynn W

No, that’s not correct. The Diesel Particulate Filter and the Diesel Exhaust Fluid (aka SCR) systems are completely separate. That said, nobody, at least I, am suggesting disabling or impairing the operation of ANY emissions control system.

Lynn W
30 days ago

It’s not only Cummins with these problems, my 2011 Duramax had constant problems with NoX sensors going bad and reporting poor DEF quality. The problem was so bad that GM extended the warranty on these sensors. Of course it was $750.00 a pop to replace them after the warranty ran out. The final straw was a DEF heater malfunction, and it was way over freezing when this happened. The truck was finally out of warranty, and living in Oklahoma with no inspections, I did what had to be done. No more problems and the truck runs great, but of course I’m now a Felon.

Richf
30 days ago

“What a deal! For less than $3,000 and one stressful week, we helped save the environment!”

This is a technology issue….let’s not blame the effort to protect the environment…..

Keith B
30 days ago
Reply to  Richf

Clearly you don’t understand the problem. Or maybe you do and you just wanted to set your straw man on fire.

Bob p
30 days ago

I was talking with my brother Friday who drives for Walmart and told him the story of the DEF head. He said people are not reading the owners manual about their situation. When the check engine light and DEF warning light comes on they have 50 miles to remedy the problem before the engine starts to derate, at that time you are limited to 55 mph for 50 miles, if nothing is done at that time the engine derates to 45 mph, ate the end of that 50 miles it will derate to 5 mph allowing you to pull off the road and call a tow truck. It is a $2500 fee to reprogram the engine computer if it gets to this level, READ YOUR OWNERS MANUAL AND PAY ATTENTION TO YOUR WARNING LIGHTS, don’t ignore them!

Bob p
30 days ago
Reply to  Bob p

He also said if you have a situation where the DEF use goes bad from aging just pee in it, after all it’s just highly filtered cow pee, that will be enough to make it ok to use.He’s been driving trucks 51 years so when it comes to a question involving trucks and Diesel engines I consider him an expert.

Don
30 days ago
Reply to  Bob p

Pee as a substitute for DEF fluid……now I have heard it all. I’m sorry your brother is giving out very bad information.

GWM
30 days ago
Reply to  Don

What do you think DEF is made of? U R I N E !!!

Keith B
30 days ago
Reply to  Bob p

Please don’t take any advice on this subject from your brother😵‍💫

Keith B
30 days ago
Reply to  Bob p

I don’t know how many times I need to say this but here goes. The problem is NOT people running out of DEF. It’s NOT people using old DEF or substituting water or peeing in the DEF tank or anything else within their control. The problem is the SENSOR that monitors all that fails and there is no provision to avoid deration even though there is no impact on emissions controls. You could pull into a truck stop 30 seconds after the light on your dash comes on and pump DEF into your vehicle until you’ve emptied the 5000 gallon underground tank and the failed SENSOR would still be indicating an empty tank.
On the other hand, I am only talking about the sensors as used on large trucks and Motorhomes. I have no idea at all whether the same issue is a problem in pickup trucks to the same degree. Unfortunately many writers, even well-meaning ones like here, regularly tend to conflate the multiple potential emission faults with this one specific situation.

JGinFL
9 days ago
Reply to  Keith B

Keith B,
Bob P didn’t say old or bad DEF is causing the sensor problem. What he did say is, IF you have a situation where the DEF use goes bad from aging just pee in it, after all it’s just highly filtered cow pee. 2 different scenarios.

Dan
30 days ago

Maybe media sources like say, RVTravel for example, could continuously publish contact information for Cummins execs and all other parties that could provide the reprogramming to flash the computers and eliminate the de-rating if needed. Bury the ‘big cigars with mail, email, phone calls etc., until the fix happens. I know you published that contact information at one time, but removed it with the promise from someone important that a solution was in the works. Maybe you could republish it in every issue until you see a positive change. Most people can search for their respective congressional members on their own, and that too could be encouraged. Remember, these are the same people that brought us mandated Tire Pressure Monitoring Systems on the premise of better fuel economy. In reality it meant a little extra profit for the manufacturers and the prospect of additional maintenance cost for the vehicle owner. Been there, paid that.

Drew
30 days ago
Reply to  Dan

No disrespect here but I can see Nancy Pelosi and Diane Feintein as she slides her glasses to the end of her nose reading my sad letter about DEF head failures and my stranded rv. 🙂

Mike Gast
30 days ago
Reply to  Dan

Dan, if you check out the links at the end of this story, you’ll see a link to a story that includes all of the emails and info on the officials you seek. Here it is again.
https://www.rvtravel.com/stuck-def-sensor-issues-mail-cummins-epa/

Jojo
1 month ago

Chrysler Dodge has known about this issue since early 2017 that I am aware of.

tom
1 month ago

Publish an address customers could voice their thoughts directly to EPA, and, of course, their Congress person. Bureaucrats made the problem. Simple code change corrects it. Not a cure, but a solution.

Mike Gast
30 days ago
Reply to  tom
Richard d Feyen
1 month ago

We too lost out on a trip due to a DEF head needing to be replaced

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