DEF sensor requirement eliminated

[scootergmc]

A step in the right direction if you ask me...

https://www.agriculture.com/epa-eliminates-def-sensor-requirement-projects-saving-farmers-usd4-4-billion-annually-11936401

 

[paul]

It’s not like I don’t want any pollution control. We all like some clean air now and then.

But that def stuff, seems to create more pollution that the tiny bit of particles it saves, if one looks at the big picture? At the least, the cost of it is more that the benefits of it in the real world.

Producing, packaging, transporting, then hauling around the def decreasing payloads on trucks, and reliability and efficiency on all equipment. Seems that is worse than the small change it made in smoke.

The def stuff costs about $15k on a big tractor or truck from what I hear?

Don’t go back to no controls, but the def seems like it was a very expensive and poor thing in the big picture.

Let’s have some common sense.

Paul

 

[RCP]

DEF is for NOx reduction not particulates

 

[jhwis]

A step in the right direction if you ask me...

https://www.agriculture.com/epa-eliminates-def-sensor-requirement-projects-saving-farmers-usd4-4-billion-annually-11936401

What goes this mean if you have currently have a tractor that uses DEF?

 

[rrman61]

Does this mean deleting the DEF system on an engine would now be acceptable/legal?not warranty wise but after warranty expires on whatever engine currently has the DEF system?of coarse this could all go right back to the way it was a few months ago with a different president in power

 

[cjunrau]

I think it means nothing. they just have a different sensor now that is not supposed to give falls readings. Same ideas as Canada now saying it will save us money by not taxing food. food never had tax just junk food. pop and chips and precooked food. Not going to save the average person anything.

 

[Jim Wendt]

Talked to a mechanic today about eliminating DEF, He said it would be very difficult to convert a tractor back to no def. They are build to use it. not just an add on.

 

[jhwis]

Talked to a mechanic today about eliminating DEF, He said it would be very difficult to convert a tractor back to no def. They are build to use it. not just an add on.

There's a delete for them I think. The whole DEF thing on a tractor defies common sense. I get it for a semi I guess but a tractor....we are dumb.

 

[scootergmc]

It's not that it's eliminating DEF, it eliminated the DEF sensor system requirement which would cause limp/derated modes and basically put a piece of equipment out of commission until "fixed."

 

[moresmoke]

The requirement for a DEF quality sensor has been removed. This is the sensor in the tank that measures the amount of urea in the DEF solution. Instead, the already present post treatment Nox sensor will be relied on to tell the system is functioning properly. Ex, If you fill the tank with water, the Nox won’t be reduced and the system will fault accordingly.

What this means for existing equipment is the MFG will be able to release a software update that no longer uses the DEF quality sensor. This sensor is usually located on the “DEF head” assembly in the tank. From the article it sounds like Deere may be on top of this, at least for units still under warranty. For current owners, you will need to check with your dealer service department to find out when such a release happens, and have them load the update.

This rule does not change any of the current emission requirements, it just removes a single failure point that is redundant in the system.

Watch for future rule making that will change the severity of the “inducement” ie. derate process to provide more time and less severe derating for after treatment faults. The trade off for that will be the amount of damage caused by continuing to operate depending on what the failure is.

 

[Sprint 6]

Useless ruling. Manufacturers are far too invested in these emission systems to turn back now. They know all it takes is a regime change and the rules will flip 180 and they'll be playimg catch-up. DEF isn't going anywhere, and is actually pretty reliable now.

These systems give plenty of warnings before derate, people just ignore the lights and choose not to stop until the truck does. I warn people with modern diesels to not ignore warning lights. Most problems can be fixed quickly when it first happens. If you run it into derate, all bets are off. My worst one to date was a diesel Colorado in derate due to a bad NoX sensor. 2 hours labor to diag and replace sensor, 6 hours labor to get it out of derate since they chose to drive until it limited the speed.

My biggested pet peeve is when a customer has it in derate AND cleared the codes with their code reader, not realizing that the system won't come out of derate just by clearing codes. Sometimes, these permanent codes are still accessible in Mode 6 data, but sometimes not. If the code is not in Mode 6 any longer, that puts me in a situation where I either have to get it to set the code again, or test every piece on the truck until we find the bad part, replace it, and hope that was it. Then I get to spend all kinds of time getting it to pass the tamper tests and hope that was the only issue. These systems can also have cascade failures if ignored. For instance, bad EGT sensors shut down regen, leading to possibly plugging the DPF or other damaged parts due to increased heat from exhaust restrictions.

Don't get me started on deleted trucks. Most of the delete parts are poor quality. And there are different ways to approach deletes, and people always choose the cheapest. Then there is the tune file. Most of the tune files are based on a single model year for the generation of truck involved. Companies don't have the R&D money to develope a special tune for every combination of year and trim level. This can lead to pesky codes that pop up due to holes in the delete file's code. Then there is the noise and smell. I've had customers be disappointed in the delete, because it was sold to them as they wouldn't know the difference, only to end up with a truck that is loud, stinks, and smokes.

 

[MarkB_MI]

Before you get too excited, read the actual letter. What it does is to remove the requirement to directly monitor DEF quality, but instead allows OEMs to rely on other sensors to determine if the system is working. Presumably if you put water in your DEF tank you're going to get an error saying the SCR system isn't working properly. So even if the DEF quality isn't monitored you'll still an error code and a check engine light.

Now let's think about how this will work out in the Real World. Today, if I dump of gallon of windshield washer fluid in the DEF tank of my diesel pickup, I'm going to get a DEF quality code and probably a warning that the truck will go into limp mode in 150 miles. So I take it into the shop and they scan the ECM to find there's a DEF quality code. Ah, that's an easy fix! Dump the DEF tank, replace the DEF quality sensor, refill with clean DEF, re-run the diagnostics and it's good to go. Probably a couple hundred bucks to fix.

Now let's re-run that scenario in a world without DEF quality sensors. Again I contaminate the DEF, and again the ECM throws a code and the check engine light goes on. HOWEVER, the code is NOT specific to DEF quality. In the case of my Chevy Duramax, it's probably code P20EE, which is "SCR NOX Catalyst Efficiency Below Threshold". This is a VERY GENERIC ERROR, and can be caused by ANYTHING in the SCR system, including:

• NOx sensor 1 or 2
• DEF pump
• DEF injector
• Bad catalytic convertor
• Urea deposits between the DEF injector and catalytic converter
• Exhaust leaks
• And, of course, bad DEF

Since there's no longer a DEF quality sensor, the technician doesn't have any reason to think the DEF is contaminated. So he loads up the parts cannon and starts shooting. He'll probably start with whatever it turned out to be on the last job he did. Let's say that was a bad DEF pump. Well, that's a ~$2K job. The good news is he'll have to dump and refill the DEF tank, which will incidentally fix the code. So, after shelling out two grand for a DEF pump I didn't need, I'm back on the road, blissfully unaware that fresh DEF would have fixed the issue.

I should add that P20EE doesn't seem to trigger limp mode. So diesel owners will probably just ignore the CEL and keep driving until the bad DEF damages something in the system, resulting in expensive repairs.