DEF Head Failure

[hrt]

Originally Posted by JMonroe

That is covered as part of the emissions system for 5 years, 50,000 miles. Depending on when your coach was originally delivered it could still be covered. This is federal law. Freightliner seems to have gotten a bad batch.

A neighbor and good friend had the same failure and was prepared to pay almost $2k to the shop that had already told him it wasn't covered after three years. I sent him a link to the DOT document. They "rechecked" and found yes, it was covered.

Do you have the link to that document? Do you know the details? I ordered a new DEF head from the parts dept at the nearby freightliner dealer today, and of course they weren't going to say anything other than "all our parts have a one year warranty".


I assume I'll just have to send the receipt to freightliner later and beg for a reimburse...

[JMonroe]

Originally Posted by hrt

Do you have the link to that document? Do you know the details? I ordered a new DEF head from the parts dept at the nearby freightliner dealer today, and of course they weren't going to say anything other than "all our parts have a one year warranty".


I assume I'll just have to send the receipt to freightliner later and beg for a reimburse...

I no longer have the link but just do a search for federal vehicle emissions laws. Note heavy vehicles, including motorhomes, are covered differently than passenger vehicles. Mainly, the covered mileage/time is shorter. 50k and 5 years vs 80 & 8.

For warranty to apply your chassis manufacturer may insist the work be done at a certified repair shop.

[Captain Slow]

Originally Posted by Captain Slow

There is one SPN code for the DEF temperature, one code for DEF Urea/water ratio and one for DEF level. I find it very interesting that all three fail at the same time.

This data should be an indicator of a problem upstream of these three sensors. On our rig, only the sensors were changed. Maybe there is a component upstream of these sensors that coverts analog signals to digital signals for transmission to the processor in the central control module.

Does anyone have experience with vehicle data bus that could comment on these thoughts.

I am still hoping that someone who is knowledgeable about how the “CanBus” network communicates, to comment why all three sensors fail at the same time. How does changing the sensor heads fix the common failure point? Shaw designed this system. Maybe someone should ask them...

[Boilervol]

Bad day - was heading out for a long awaited HWH active air install ( had to cancel last spring because of Covid travel issues). I have been following this issue and hoping it would at least not happen until after the HWH install. Fired the coach up today and got the dreaded DEF fault codes. The coach is now sitting at Cummins waiting on parts. At least it happened in our backyard. The next HWH install is now March 22,2021.That’s exactly one year later than the first install date. I told Ashley at HWH I’d come one week early just to make sure we get there this time.

[arcaguy]

Just to pass along information on this subject from another group. International chassis with Cummins engines are also having problems with DEF sensors. This leads me to believe that this is a Cummins related issue and not specific to any chassis. I also have heard that the a redesigned DEF head from a different supplier that fixes this issue. None of this is confirmed but then again what is? Good luck.

[sponserv]

I am not sure if this has been compiled yet. But is there an appetite for doing a poll regarding def head failures? Perhaps we could format it as such:


Coach Year and Model:


Chassis Manufacturer:


Engine:


Mileage at failure:


Resolution:


Covered under Fed Emissions Warranty:

[joslawrence]

Thought I would put this information here for anyone that may find it helpful…there is a company called OTR performance that is selling a plugin diagnostic tool that will allow the user to reset the fault codes that will put the rig into Limp mode. For a failure of DEF system or some other systems that are not truly critical you can get your rig out of limp mode and perhaps to a location where you can do service without being in a dangerous situation or face a very expensive towing bill and risk possible damage during towing of your coach, which is very likely unless you get a tow operator that really knows what he is doing. This tool is primarily being marketed to fleet operations so that a truck in limp mode can be brought into service at greater than 5mph and avoid a costly and potentially dangerous, side of the road, shutdown.

So here is my experience…they offer this setup in three versions, the basic plugin is dedicated to just one vehicle with limited readouts of the faults but the ability to reset DEF errors and others, this is priced at $400.00. The next step up is priced at $600.00 and offers a little more in the way of diagnostics. It is a subscription service so this is a yearly price. I may not like the marketing scheme but I thought, if I did have a DEF problem that put me into a 5mph situation, and I could get out of 5mph for a time it was worth $400 as insurance. I decided I would buy the “Plus” version and just have it handy. My coach is a 2016 DS with 30,000 miles. Well that was about 7 weeks ago.

A few weeks ago I started to noticed that my engine brake was not activating consistently when braking. I was not sure what the problem was and I had an appointment with my local Freightliner dealer for a regular PM so I asked them to check it out. They did check into it and could find nothing, no error codes or any failure in the activation of the braking trigger for the engine brake system. So I left with the coach and went away for the weekend. On the trip I had several occasions more where the engine brake would not activate. I reached my destination and spent my time, then on the way home I again had the engine brake fail and then all of a sudden my orange engine light came on. I was not sure what it meant and everything seemed to be working properly. I continued for about 15 miles then suddenly the red light came on! As soon as I slowed down it would not allow acceleration the light flickered on and off a few times which I think was the system allowing a few errors to occur before going to limp mode. But after just a few minutes it went into limp mode and I was stuck at a max of 5mph. I was on a two lane country road on Sunday evening but fortunately I came upon a gravel lot that I could pull into. I had no idea of what the problem was but I thought, well here is an unexpected opportunity to use the diagnostic tool and see if I can see what the problem may be! I had never hooked up the tool so I had to read the info and get it hooked up and connect to it via my cellphone. After making the connection I quickly was able to read the fault codes and could see the error was from my accelerator position sensor.

Now while not being part of the emissions or DEF system I now was pretty certain that I did know what the problem was. Before hooking up the tool I had tried to shut down and restart several times. Each time, as soon as I touched the accelerator, it would bring up the red light and limit the engine. So now I thought I will try to use the tool to reset the faults and see what that would do. Sure enough, after doing the reset, I could accelerate, so I thought I am only about 90 miles from home perhaps I can get back. So I started out…well after about 10 miles I had the fault again but this time after reset it would occur very quickly again. After about 3 tries it would go into a hard failure where it would not even try to accelerate and would immediately put the red light on. Since I knew the problem was in the position sensor, on the accelerator pedal, with the OTR tool I was able to reset the faults several times and eventually I was able to coax the speed up to about 45 mph without putting it into limp mode. I then put on the cruise which would keep it at that speed because there was no input from the pedal and it was not error-ing out. I decided to go about 20 miles to a nearby campground where I spent the night and was able to get to a Freightliner dealer, buy the replacement part ($90), put it on in about 10 min and was on my way, VERY happy that I avoided a large towing bill, a large diagnostic and repair bill and a HUGE inconvenience. Now while this was not a DEF problem if this tool can get me out of a problem like this…if I ever have DEF problem the price is TOTALY worth it! Incidentally, this also was causing my engine brake problems over the past few weeks. So now along with the OTR tool I am also going to carry a spare accelerator position sensor.

[JMonroe]

I have a couple questions for those that have suffered DEF head failures.

Do you refill at the truck stop or from a container?

Are you carefull about not filling above the max fill line?

[Niblet]

Originally Posted by joslawrence

Thought I would put this information here for anyone that may find it helpful…there is a company called OTR performance that is selling a plugin diagnostic tool that will allow the user to reset the fault codes that will put the rig into Limp mode. For a failure of DEF system or some other systems that are not truly critical you can get your rig out of limp mode and perhaps to a location where you can do service without being in a dangerous situation or face a very expensive towing bill and risk possible damage during towing of your coach, which is very likely unless you get a tow operator that really knows what he is doing. This tool is primarily being marketed to fleet operations so that a truck in limp mode can be brought into service at greater than 5mph and avoid a costly and potentially dangerous, side of the road, shutdown.

So here is my experience…they offer this setup in three versions, the basic plugin is dedicated to just one vehicle with limited readouts of the faults but the ability to reset DEF errors and others, this is priced at $400.00. The next step up is priced at $600.00 and offers a little more in the way of diagnostics. It is a subscription service so this is a yearly price. I may not like the marketing scheme but I thought, if I did have a DEF problem that put me into a 5mph situation, and I could get out of 5mph for a time it was worth $400 as insurance. I decided I would buy the “Plus” version and just have it handy. My coach is a 2016 DS with 30,000 miles. Well that was about 7 weeks ago.

A few weeks ago I started to noticed that my engine brake was not activating consistently when braking. I was not sure what the problem was and I had an appointment with my local Freightliner dealer for a regular PM so I asked them to check it out. They did check into it and could find nothing, no error codes or any failure in the activation of the braking trigger for the engine brake system. So I left with the coach and went away for the weekend. On the trip I had several occasions more where the engine brake would not activate. I reached my destination and spent my time, then on the way home I again had the engine brake fail and then all of a sudden my orange engine light came on. I was not sure what it meant and everything seemed to be working properly. I continued for about 15 miles then suddenly the red light came on! As soon as I slowed down it would not allow acceleration the light flickered on and off a few times which I think was the system allowing a few errors to occur before going to limp mode. But after just a few minutes it went into limp mode and I was stuck at a max of 5mph. I was on a two lane country road on Sunday evening but fortunately I came upon a gravel lot that I could pull into. I had no idea of what the problem was but I thought, well here is an unexpected opportunity to use the diagnostic tool and see if I can see what the problem may be! I had never hooked up the tool so I had to read the info and get it hooked up and connect to it via my cellphone. After making the connection I quickly was able to read the fault codes and could see the error was from my accelerator position sensor.

Now while not being part of the emissions or DEF system I now was pretty certain that I did know what the problem was. Before hooking up the tool I had tried to shut down and restart several times. Each time, as soon as I touched the accelerator, it would bring up the red light and limit the engine. So now I thought I will try to use the tool to reset the faults and see what that would do. Sure enough, after doing the reset, I could accelerate, so I thought I am only about 90 miles from home perhaps I can get back. So I started out…well after about 10 miles I had the fault again but this time after reset it would occur very quickly again. After about 3 tries it would go into a hard failure where it would not even try to accelerate and would immediately put the red light on. Since I knew the problem was in the position sensor, on the accelerator pedal, with the OTR tool I was able to reset the faults several times and eventually I was able to coax the speed up to about 45 mph without putting it into limp mode. I then put on the cruise which would keep it at that speed because there was no input from the pedal and it was not error-ing out. I decided to go about 20 miles to a nearby campground where I spent the night and was able to get to a Freightliner dealer, buy the replacement part ($90), put it on in about 10 min and was on my way, VERY happy that I avoided a large towing bill, a large diagnostic and repair bill and a HUGE inconvenience. Now while this was not a DEF problem if this tool can get me out of a problem like this…if I ever have DEF problem the price is TOTALY worth it! Incidentally, this also was causing my engine brake problems over the past few weeks. So now along with the OTR tool I am also going to carry a spare accelerator position sensor.

where can we get this tool? do you need a cellular connection to make it work? GREAT info! thanks!

[KennyGolub]

I purchased this one that is supposed to do the same thing.


Scan Tool


Haven't had to use it yet other than to make sure it does "talk" to the ECM


.

[hrt]

Originally Posted by KennyGolub

I purchased this one that is supposed to do the same thing.


Scan Tool


Haven't had to use it yet other than to make sure it does "talk" to the ECM


.

Does it plug into the round connector behind the engine?

[hrt]

Originally Posted by JMonroe

I have a couple questions for those that have suffered DEF head failures.

Do you refill at the truck stop or from a container?

Are you carefull about not filling above the max fill line?

I refill at Pilot truck stops. I fill until the pump stops.


The cummins road side tech was telling me how only two companies make the DEF sensors, and both have issues. The one that is NOT what is on my chassis tends to read full even when empty. Most of his work is dealing with those - from mobile generators at the airport and a data center, to truck feets... He also checked the quality of the DEF in my tank, it was good.



So I suspect that theories that filling up at truck centers might be the cause are probably misguided.


This incidentally is why the derate to 5mph is downright unethical. If everyone knows that the sensors are unreliable, then until those problems are fixed, motorists' lives should not be put in danger.

[JMonroe]

hrt, what I'm wondering is does an overfill "flood" the head? Ours has a fill on the left side but I'm afraid to use it as I wobe able to monitor/control the level. The max fill line is well below the head.

[hrt]

Originally Posted by JMonroe

hrt, what I'm wondering is does an overfill "flood" the head? Ours has a fill on the left side but I'm afraid to use it as I wobe able to monitor/control the level. The max fill line is well below the head.

I'll check for that next time I fill, but I just filled on the way in so it'll be awhile.


I've never filled DEF right before stopping, so it wouldn't be just sitting there and crystalizing, at least. I could see that being a problem.