PSA and rant if you have a modern diesel with an exhaust aftertreatment system

[bacon#1]

I had a Passat tdi for a hot minute. The dealer just kept reiterating, DON'T RUN THIS LOW ON DEF. 10k miles later took it in for an oil change still wasn't low. Good car, mated to a six speed manual.

 

[crewchief888]

It is a Mercedes. He mentioned World Wide Motors.

BTW, I am pretty sure the DEF system shuts itself off if the temps are below a certain number. I wonder how those government totalitarians reconcile this with a supposedly cleaner environment? Don't polar bears and snow geese need clean air too?

im in the const eq field, DEF will freeze, (it's mostly water) our system surges the DEF lines and injectors when th engine is shut off. there are coolant lines that run through the def tank to warm it up above freezing in cold weather. newer diesels warm up extremely fast compared to the older non common rail engines.
the biggest problem i run across is an operator letting the DEF tank run dry, the DEF pump senses a "problem" ( the tank is empty) sets fault codes and derates, or shuts down the engine. i get a service call, "it wont start" then they refill the tank and it runs fine by the time i get there.
i can see the stored fault codes, and politely inform them "dont run the tank dry"
while muttering to myself "dumbass"

ive had multiple calls to the SAME customer over the past couple months for the SAME problem..

 

[edporch]

Benz. Overall I'd say it's been good to us, almost 8 years and 105k, used for towing, traveling, and the daily grind. We went diesel for the power and milage at the time, the emissions stuff was too new to really get a feel for how troublesome it could be. Since it's paid off and the wife still likes it we can put a lot into maintenance and still be better off than replacing it. Our plan is to drive it until the wheels fall off but were thrown off by the sudden self destruct mode activation. We were under the impression that it would only happen if the DEF tank was empty and that we would get more than a 16 start warning. According to my eyeballs, scanner, and the IP the tank is full.

In the past I've just filled it when it said it was low and it's never complained. Apparently this time was different.

what's a warranty? We haven't had a vehicle under warranty since sometime in 2014.

I was wondering.
Your 16 starts experience sounded scary and like a big hassle.

I have a 2015 Duramax Diesel, GMC 3/4 ton 4WD.

It's been great so far.

I got the 7 year warranty on it when I bought it new.

If memory serves, it says it'll be limited to 50mph if the exhaust fluid runs out.

 

[jkaetz]

Just because I need to rant again, no problems since last year until a CEL popped up after our 450 mile trip to Wisconsin on Tuesday. Today I went to the local auto parts store just to read the code (didn't pack my good scanner). Code reader could only say something generic about NOx emissions. I think, ok no problem we can deal with that when we get home, likely an NOx sensor issue. On the way back to the MIL's house the start countdown came up with 16 starts remaining. Needless to say I am currently pursuing a more radical solution to the problem than a dealership. It's unfortunate that emissions are more important than a functioning vehicle.

 

[femurphy77]

Because. . . FEELINGS!!!

 

[CTC B4Z]

This stuff pays my bills so I ain't even mad

 

[jkaetz]

This stuff pays my bills so I ain't even mad

Doing the repairs or the initial engineering?

I don't really mind the tech if it reduces the emissions, but to disable vehicles for a fault is unbelievably infuriating. You can still run engines with no oil or coolant until they sieze but have an emissions fault any it will turn itself into a roadblock in a very short time period. I feel like i drew the go directly to jail chance card.

 

[russc2542]

Doing the repairs or the initial engineering?

I don't really mind the tech if it reduces the emissions, but to disable vehicles for a fault is unbelievably infuriating. You can still run engines with no oil or coolant until they sieze but have an emissions fault any it will turn itself into a roadblock in a very short time period. I feel like i drew the go directly to jail chance card.

The root cause is the gov't. they mandate the emissions have to be X and the engine can't vary for the warranty period... which they specify the length of. In order to keep the emissions in check, not only does the engine have to produce low emissions when running right but the mfr has to prevent engine operation with high emissions thus the start disable. they also have to prevent further damage to the emissions system. While the execution is up to the mfrs, the requirements to be met are up to the gov in order to be allowed to sell the engine.

 

[jkaetz]

The root cause is the gov't. they mandate the emissions have to be X and the engine can't vary for the warranty period... which they specify the length of. In order to keep the emissions in check, not only does the engine have to produce low emissions when running right but the mfr has to prevent engine operation with high emissions thus the start disable. they also have to prevent further damage to the emissions system. While the execution is up to the mfrs, the requirements to be met are up to the gov in order to be allowed to sell the engine.

I was aware that this was an EPA initiative. Unfortunately they don't provide a path after the warranty period. Nor are the exhaust after treatment systems covered by the fed emissions warranty. IMO any system that forcibly disables the vehicle should be repaired for the life of the vehicle or provide the customer with a bypass path after the warranty period is over. The engine disabling for all faults of the after exhaust treatment system should also be disclosed to buyers at the time of sale. No where is this stated that faults disable the engine, only an empty DEF tank is called out as a condition for disablement.

If all goes to plan this will all be behind us by early next week.

 

[CTC B4Z]

Doing the repairs or the initial engineering?

I don't really mind the tech if it reduces the emissions, but to disable vehicles for a fault is unbelievably infuriating. You can still run engines with no oil or coolant until they sieze but have an emissions fault any it will turn itself into a roadblock in a very short time period. I feel like i drew the go directly to jail chance card.

Repairs.

Emissions controls work. DPF works... I recall a certain Ohio school board retro fitting all older buses with dpf/egr... Within 2 years the student absences from being sick were all but gone.

This stuff works, but I agree, to a certain degree they're targeting the wrong sector.

 

[russc2542]

I was aware that this was an EPA initiative. Unfortunately they don't provide a path after the warranty period. Nor are the exhaust after treatment systems covered by the fed emissions warranty. IMO any system that forcibly disables the vehicle should be repaired for the life of the vehicle or provide the customer with a bypass path after the warranty period is over. The engine disabling for all faults of the after exhaust treatment system should also be disclosed to buyers at the time of sale. No where is this stated that faults disable the engine, only an empty DEF tank is called out as a condition for disablement.

If all goes to plan this will all be behind us by early next week.

but... but...
By the time the warranty's up you should have replaced it.
It's not disabling: you have 16 starts to get it to the dealership and fixed.
It's OK, it's for the environment.
Think of the CHILDREN!

I don't disagree with any point in particular, as much putting it out there for all to read.

My father-in-law teaches and drives a school-bus. before they upgraded to newer busses with all the emissions stuff, he'd wear a dust mask (for all his education, brilliant...) due to headaches, lightdeadedness, etc from the exhaust in the bus line after school. After going to newer busses, no more problems. He's also one of the few drivers that isn't always plugging the DFPs because smooth and steady. Other drivers in the district are binary: floor the gas, floor the brake. smoke like a coal train, filling the DPF, then cool the exhaust to not burn it off.

Emergency vehicles have the same problem: they're usually idling in a parade or run hard and put away wet. They don't spend an hour each week on the interstate to clean the DPF. Many of the newer systems are much better about running stationary/induced regens rather than failing catastrophically but far from perfect.

 

[BugI02]

Caveat: I have no direct or detailed knowledge of these systems, but I have developed workarounds for some motor vehicle limiting systems

It seems like it should be possible through hardware or software mods, or both, to convince the ECM that the DEF tank is always full. This may involve quite a bit of tweaking secondary inputs, such as; do the injector(s) or pump know they're sucking air and report that to the ECM even if the tank is reporting full? There are undoubtedly people out there who have done/can do this work, they're just not going to be advertising it. Do you know anybody in racing? Find someone who tow their kit using your type of truck and see what they know/are willing to admit they have done

 

[Nazgul]

Caveat: I have no direct or detailed knowledge of these systems, but I have developed workarounds for some motor vehicle limiting systems

It seems like it should be possible through hardware or software mods, or both, to convince the ECM that the DEF tank is always full. This may involve quite a bit of tweaking secondary inputs, such as; do the injector(s) or pump know they're sucking air and report that to the ECM even if the tank is reporting full? There are undoubtedly people out there who have done/can do this work, they're just not going to be advertising it. Do you know anybody in racing? Find someone who tow their kit using your type of truck and see what they know/are willing to admit they have done

There are work arounds, the penalties for using them are vicious. Especially if it is a company owned vehicle. Ours would have run into the 10's of thousands of dollars per vehicle.

Don

 

[ATOMonkey]

There are work arounds, the penalties for using them are vicious. Especially if it is a company owned vehicle. Ours would have run into the 10's of thousands of dollars per vehicle.

Don

Absolutely this! If you get caught disabling emissions control systems (or even modifying) on a road vehicle, there can be some pretty hefty fines.

Perfectly acceptable to do for an offroad vehicle though...

Modern computer logic doesn't even allow for you to trick sensors anymore. It used to be that you could just plug in a dummy sensor and be done with it. Now, if the computer sees that the sensor readings aren't changing enough, it will throw a fault. So, you would need a random number generator that created a 5V-ish signal in the normal range.

The up side is that stand alone engine management systems are getting to be really good.

 

[jkaetz]

but... but...
By the time the warranty's up you should have replaced it.
It's not disabling: you have 16 starts to get it to the dealership and fixed.
It's OK, it's for the environment.
Think of the CHILDREN!

I don't disagree with any point in particular, as much putting it out there for all to read.

My father-in-law teaches and drives a school-bus. before they upgraded to newer busses with all the emissions stuff, he'd wear a dust mask (for all his education, brilliant...) due to headaches, lightdeadedness, etc from the exhaust in the bus line after school. After going to newer busses, no more problems. He's also one of the few drivers that isn't always plugging the DFPs because smooth and steady. Other drivers in the district are binary: floor the gas, floor the brake. smoke like a coal train, filling the DPF, then cool the exhaust to not burn it off.

Emergency vehicles have the same problem: they're usually idling in a parade or run hard and put away wet. They don't spend an hour each week on the interstate to clean the DPF. Many of the newer systems are much better about running stationary/induced regens rather than failing catastrophically but far from perfect.

I'm happy that we're developing ways to keep emissions in check and commercial vehicles running in the 50 - 100k+ miles/year range should make sure those systems are functioning properly. A family vehicle driven < 15-20k/year should not be forced to drop everything and immediately run it in for service simply because the emissions system has a fault. Even more so when the vehicle is way out of warranty and the cost of labor & parts will likely equal 50% or more of the vehicle's current value if they can even figure out what the issue is without simply throwing parts at it.

We haven't had any DPF issues as it usually gets a good run on the interstate twice daily. Though sometimes we'll pull into the garage after a long trip only to hear the engine fan hit full speed on shutdown because it was in the middle of a regen cycle. Great for heating the garage in the winter, not so much in the summer. They really should include a meter/indicator that a regen is needed or active. Most of the time it wouldn't be an issue to lengthen the drive.

Caveat: I have no direct or detailed knowledge of these systems, but I have developed workarounds for some motor vehicle limiting systems

It seems like it should be possible through hardware or software mods, or both, to convince the ECM that the DEF tank is always full. This may involve quite a bit of tweaking secondary inputs, such as; do the injector(s) or pump know they're sucking air and report that to the ECM even if the tank is reporting full? There are undoubtedly people out there who have done/can do this work, they're just not going to be advertising it. Do you know anybody in racing? Find someone who tow their kit using your type of truck and see what they know/are willing to admit they have done

Yes, there are. They change and evolve regularly. Initially you had to send off an ECU. Then you could crack it open and program with special software. When I looked into them last year it was a simulator module. Now it is an OBD plug that can re-program the ECU.

Absolutely this! If you get caught disabling emissions control systems (or even modifying) on a road vehicle, there can be some pretty hefty fines.

Perfectly acceptable to do for an offroad vehicle though...

Modern computer logic doesn't even allow for you to trick sensors anymore. It used to be that you could just plug in a dummy sensor and be done with it. Now, if the computer sees that the sensor readings aren't changing enough, it will throw a fault. So, you would need a random number generator that created a 5V-ish signal in the normal range.

The up side is that stand alone engine management systems are getting to be really good.

For the most part there's no need to go stand alone yet. Dummy sensors still exist but they're not as dumb now.

Our problem seems to have been resolved. Now we'll see what the next issue is. I just remind myself of the monthly payments that I'm not making, until a major mechanical component breaks it's far more financially efficient to make repairs.