DEF Header failure

[NMBluept]

Here we are at the Knoxville Cummins shop with the dreaded "low DEF" error, check engine indicator, and flashing red low DEF gage. Diagnosis = failed DEF header. I've read all about this, but none of the threads mentioned Freightliner XCR with Cummins ISB. This is a Tiffin Allegro RED 33AA with Cummins 6.7 ISB
The fun part is trying to get someone/anyone to cough up the DEF header. Tiffin tells me it is a Freightliner part, Cummins repair shop tells me they have replaced at least 20 with parts from Tiffin. Local Freightliner shop tells me they have none and no eta on any. The Tiffin contact (Ricky Brown) is conveniently not returning phone calls or email from myself or the Cummins service writer.
I'm looking for suggestions on how to get the part so I can get on the road. The idea of spending multiple days at the Cummins shop is not part of our plans. At least they have a 30 amp electric outlet for us.

[ekim]

Powerglide chassis will come from Tiffin, but Freightliner chassis will come from Freightliner.

I would avoid middle men and get your chassis vin (call Tiffin for it if needed). Then call Freightliner with your diagnosis - engine codes, number of occurrences, if there's an active MIL etc.

If you call Tiffin - ask them for the Freightliner phone number- or ck Tiffin web site under owners section it might be there.

Someone at Freightliner should be able to at least give an ETA. Make it clear to then that your are currently down on the road as you may get higher priority cs someone just looking for spares or even down but at a campground or at home.

[NMBluept]

Update:
After spending yesterday pretty much spinning my wheels with many calls to Tiffin and Freightliner, this morning I found a DEF Header at Premier Trucks (Knoxville Freightliner shop) . Very surprised because yesterday they didn't have any, but this morning there was 1 in stock. Had the Cummins shop start the process to make a claim against my service plan. Double checked with Premier to ensure they didn't let that DEF header get away. He said Cummins had ordered the part and that he had another call for one! "Is it okay if I go ahead and let them have the part?" - quite the comedian:-) Hopefully we can get the work done today and at least get to a campground instead of the side of the Cummins shop.
FCC in Gaffney recommends having the local Freightliner parts people order the DEF header as a "critical need" part by creating what they call an ATC ticket. This indicates the part is for a broken down coach which will prioritize it over orders for spares or common stock.
Stay tuned for the next chapter in this little saga.

[Crasher]

Out of curiosity, I called Tiffin to inquire about buying a spare Head just in case mine should fail in the future. They have 65 on order, so I placed an order to be shipped when they get them in. About $675 for something I may never need, but worth far more than that if mine should fail on the road somewhere.

[vito.a]

Crasher, as I understand it your 2013 model should be the older style and is more reliable. 2016 and newer incorporate the new EPA requirements.

[NMBluept]

Update:
DEF header is on-hand and tech started replacement ~3:00 (shop closes @4:00) once he got the header free it is too long to remove so will have drop the tank. Work to continue in the morning.
How does one tell what generation DEF header is installed (or does this only apply to Spartan headers)?
BTW: the Freightliner list price is $754.02, FL part # 04-31353-004

[Crasher]

Originally Posted by vito.a

Crasher, as I understand it your 2013 model should be the older style and is more reliable. 2016 and newer incorporate the new EPA requirements.

I realize that, but it's worth the price to me to know if I have a failure, I can be back on the road in a day rather than a week or two.

[Dutch Star Don]

Originally Posted by Crasher

I realize that, but it's worth the price to me to know if I have a failure, I can be back on the road in a day rather than a week or two.

My friend has a 2019 Allegro Bus and out of caution, ordered a spare from Tiffin, but it was a few months ago, before the part supply got so critical. Rather than shipping him the entire DEF head, they sent just the sensor, which was the sensor with a tube attached. Apparently, on his Powerglide chassis, just this sensor can be replaced. He paid $300.00. He later checked and I guess with shortages of various parts, Tiffin is no longer selling spare parts and will only ship something when it's critical to replace a broken part.

Last week, he was at a campground and met a couple with a new Cornerstone, the day they left, while connecting their toad, they got a DEF head failure. The Cornerstone owner knew my friend had the part and offered to buy it. My friend gave it to him, with the understanding that he got it back unused if Spartan provided a new one right away, or he got the new replacement, when it was made available. My friend is a good guy and very trusting, I applaud him for giving up the spare part.

Later he was contacted by the Cornerstone owner who discovered that the spare sensor was the wrong length. My friends Allegro Bus has the 450 ISL and has a tall narrow DEF tank. The Cornerstone has the 605 ISX, and has a larger, but shorter DEF tank. The Cornerstone owner shipped the sensor back to him. It ended well.

Like you, I bought a spare, unfortunately the Freightliner part is $1400.00.

[NMBluept]

We are back on the road :-) The DEF tank had to be drained and removed to install the new header, so a bit more complex than expected. Upon reconnecting everything and clearing codes the problem still existed. The tech stated it acted as if there were a plug disconnected, but nothing found. Another tech came over and asked where the chassis fuse box was. After a short search we found it sure enough a blown 4 amp fuse. Fuse replacement made all well. I asked if that could have been the original problem - no, the sensor likely got wet and shorted. The header connector only has 4 pins: gnd, 12v, and 2 data link. That must be a pretty sophisticated piece of silicon if it can provide DEF level, quality, & temp. The thing looks very simple: 2 3/8" connections for heat (engine coolant), a 1/4" DEF supply (with a strainer) and a 1/4" DEF return. There seems to be several configurations of these headers but I bet they all use the same semiconductor device. Some food for thought in my case if the sensor chip was exposed to DEF then the enclosure failed causing the chip failure in which case the chip would not be the weak point.
At this point I am just happy to be continuing our travels.

[MN_Traveler]

I’m really just now scanning this thread … have not previously heard of this failure mode on newer def systems. Just how widespread and frequent is this problem, and is it across chassis and MH builders?

If I have a 2017 newmar with ISX and a freightliner chassis, it sounds like my rig might be in the group potentially affected?
EDIT - just read through the other current thread. Seems like issues with freightliner are fewer .. so no need to answer the above question)

[JerryP]

Originally Posted by NMBluept

We are back on the road :-) The DEF tank had to be drained and removed to install the new header, so a bit more complex than expected. Upon reconnecting everything and clearing codes the problem still existed. The tech stated it acted as if there were a plug disconnected, but nothing found. Another tech came over and asked where the chassis fuse box was. After a short search we found it sure enough a blown 4 amp fuse. Fuse replacement made all well. I asked if that could have been the original problem - no, the sensor likely got wet and shorted. The header connector only has 4 pins: gnd, 12v, and 2 data link. That must be a pretty sophisticated piece of silicon if it can provide DEF level, quality, & temp. The thing looks very simple: 2 3/8" connections for heat (engine coolant), a 1/4" DEF supply (with a strainer) and a 1/4" DEF return. There seems to be several configurations of these headers but I bet they all use the same semiconductor device. Some food for thought in my case if the sensor chip was exposed to DEF then the enclosure failed causing the chip failure in which case the chip would not be the weak point.
At this point I am just happy to be continuing our travels.

Albert,
I just build a DEF head simulator. It uses a 4 pin male connector with the connections that you described. I have a 2020 Tiffin 33AA and it probably has the same DEF head with connector. Do you have a closeup picture of the connector or do you have the Freightliner part number that was replaced.
Some people have said that Freightliner might use a different connector than the ones used on the simulator kit parts list. Thanks, Jerry

[SlowJoe]

They have engineered the reliability out of diesels.... It's a shame they put all of this non-essential mess on them now.

[Ray,IN]

DEF sensor simulator. You can make one yourself.https://defsim.myervin.com/

[mgoldstone]

Originally Posted by NMBluept

Here we are at the Knoxville Cummins shop with the dreaded "low DEF" error, check engine indicator, and flashing red low DEF gage. Diagnosis = failed DEF header. I've read all about this, but none of the threads mentioned Freightliner XCR with Cummins ISB. This is a Tiffin Allegro RED 33AA with Cummins 6.7 ISB
The fun part is trying to get someone/anyone to cough up the DEF header. Tiffin tells me it is a Freightliner part, Cummins repair shop tells me they have replaced at least 20 with parts from Tiffin. Local Freightliner shop tells me they have none and no eta on any. The Tiffin contact (Ricky Brown) is conveniently not returning phone calls or email from myself or the Cummins service writer.
I'm looking for suggestions on how to get the part so I can get on the road. The idea of spending multiple days at the Cummins shop is not part of our plans. At least they have a 30 amp electric outlet for us.

If handy with electronics there is a work around that will get you back on the road while the dealer/repair shop acquires the replacement part...

Google "DEF Sensor Simulator - Quick Build" Read the article and make sure it's compatable with your rig.

This is a module that you would program using a PC and that then connects to the wiring harness where the DEF head (sensor) was connected. It reports the correct viscosity, temperature and DEF fluid level so the pollution control continues to operate. You will have to manually check DEF levels until your replacement part is available.

I think this thing is just the sort of insurance policy we RVers need as there are too many such failures...