Maybe this? https://static.nhtsa.gov/odi/tsbs/2014/SB-10069277-9133.pdf

 

Ron,
Thank you I have found this before. Mine is 2017 I believe they correct that issue before 2017, i will look again. The thing that has me baffled is i have volts on all terminals at the plus for the NOX. If it was a short i would think one would read zero?

 

I recall reading somewhere on here that Def PLATINUM should not be used on dmax's, but I don't recall which thread that was in or why that version was bad for our trucks.
I also recall reading that the snap on unit is not able to clear codes that deal with emissions codes, it has to be cleared with a GM scanner.

Maybe someone else who recalls these two issues can shed some light on them, or maybe do some fine-tuned searching here for those things I've mentioned. Hope it helps you to find solutions to your issues.

 

You can also have a short to power.

 

Thank you,

If i have a short to power would the power coming still read 12 Volts?

 

Depends on the resistance at the short point.

 

Thank you, How would i test or check for this? Test for a short in the wire? I have basic knowledge and tools/testers.

 

Hello Everyone,
I have been following this forum for a while and I enjoy reading all the information, now it is my turn with issues I guess. Very long post but I tried to cover it all

I have a 2017 Chevy Silverado 2500 HD LTZ with the 6.6 in it. Truck has 80k miles and all stock. I am the second owner of this truck and primarily use it for hauling at work and towing on the weekends. 8,000 pound camper. Truck handles like nothing is behind it.

I started having some issues a few months ago. It seemed every time the truck would go into a regen cycle the check engine light would come on. I never had the code read like a dummy. However it would clear itself after a few miles. Well i started reading forums and one i came across was that these trucks can be sensitive to the type of Def you run. So i changed to Def platinum, before i would just run blue def I always refill when i see its at 20% my truck does not really have a gauge just says ok until i get down to 20%. So i decided to run it down as low as i could before switching over to the platinum blue def. That is when the problem started, i believe I was at 10% and the Def light and check engine lights came on I thought well that's because it is low, the truck went into limp mode 65 Mph max for 100 miles or something. I filled the tank when i got home and the light and warning went away a day or so later. I thought problem solved and it did for a while. I took my truck in for service oil change and fuel filter, when i picked up the truck the def light was on again and it was in limp mode. The place that changed the filters said they tried to clear it and the code would not clear.

Fast forward to now, i have been looking at all the forums and tech pages all i can find for this code is Lost communication, I checked voltage on each plug terminal and i have power and ground so i thought i was good and the sensor was bad, i changed the NOX sensor and pigtail plug as one terminal looked funny. Took truck to the shop hooked it up to the Snap on machine and went through the re lean for the new sensor and it still will not let us clear the code and still in limp mode and same code.

I looked again for new info and what i found is the pins inside the plug to the Nox Sensor should have certain voltage, so i tested each of mine. Plug has 6 wires, Here are the results. Ground good, Power 12.6V, Then 4 other wires on the sensor, 3 of the 4 read between 2.8V - 3.5 V. The 6th Wire reads 1.8 Volts I thought that was weird so i traced it and didn't find any shorts or marks on the wire, that wire goes to the fuel pump driver control module. No codes came up for that module at the time. However after doing some testing and playing around i had a code of U18A2 pop up which is for that Module not communicating. The scanner let me clear the code which I did. However the original Code of U29E remains.

After all of that very long description my question is has anyone else run into this? I thought maybe the Fuel pump module is failing and that's why i am only getting 1.8 V from it. However i dont want to just start changing random expensive parts if i dont know the root cause of the problem. That module is 300 bucks from what i have found and it has to be programed?

Anyone have similar issues? I am at 25 Miles until 5 Mph so truck is currently parked and not making any money.

Hello Everyone,
I have been following this forum for a while and I enjoy reading all the information, now it is my turn with issues I guess. Very long post but I tried to cover it all

I have a 2017 Chevy Silverado 2500 HD LTZ with the 6.6 in it. Truck has 80k miles and all stock. I am the second owner of this truck and primarily use it for hauling at work and towing on the weekends. 8,000 pound camper. Truck handles like nothing is behind it.

I started having some issues a few months ago. It seemed every time the truck would go into a regen cycle the check engine light would come on. I never had the code read like a dummy. However it would clear itself after a few miles. Well i started reading forums and one i came across was that these trucks can be sensitive to the type of Def you run. So i changed to Def platinum, before i would just run blue def I always refill when i see its at 20% my truck does not really have a gauge just says ok until i get down to 20%. So i decided to run it down as low as i could before switching over to the platinum blue def. That is when the problem started, i believe I was at 10% and the Def light and check engine lights came on I thought well that's because it is low, the truck went into limp mode 65 Mph max for 100 miles or something. I filled the tank when i got home and the light and warning went away a day or so later. I thought problem solved and it did for a while. I took my truck in for service oil change and fuel filter, when i picked up the truck the def light was on again and it was in limp mode. The place that changed the filters said they tried to clear it and the code would not clear.

Fast forward to now, i have been looking at all the forums and tech pages all i can find for this code is Lost communication, I checked voltage on each plug terminal and i have power and ground so i thought i was good and the sensor was bad, i changed the NOX sensor and pigtail plug as one terminal looked funny. Took truck to the shop hooked it up to the Snap on machine and went through the re lean for the new sensor and it still will not let us clear the code and still in limp mode and same code.

I looked again for new info and what i found is the pins inside the plug to the Nox Sensor should have certain voltage, so i tested each of mine. Plug has 6 wires, Here are the results. Ground good, Power 12.6V, Then 4 other wires on the sensor, 3 of the 4 read between 2.8V - 3.5 V. The 6th Wire reads 1.8 Volts I thought that was weird so i traced it and didn't find any shorts or marks on the wire, that wire goes to the fuel pump driver control module. No codes came up for that module at the time. However after doing some testing and playing around i had a code of U18A2 pop up which is for that Module not communicating. The scanner let me clear the code which I did. However the original Code of U29E remains.
.
t
After all of that very long description my question is has anyone else run into this? I thought maybe the Fuel pump module is failing and that's why i am only getting 1.8 V from it. However i dont want to just start changing random expensive parts if i dont know the root cause of the problem. That module is 300 bucks from what i have found and it has to be programed?

Anyone have similar issues? I am at 25 Miles until 5 Mph so truck is currently parked and not making any money.

"COOP", I will try to not get to emotional.
I have a 2020 GMC SIERRA DENALI 6.6, not sure of the motor class, think it's irrelevant.
All of the same issues right down to the de-rate to 5mph.
The truck has been at a local dealer for a month now, WAITING FOR PARTS is what I'm told.
I have a consumer advocate and a claim number after contacting GM customer service, nice woman but I believe her job is to blow smoke up my ass!
Yesterday's phone call went BAD in a hurry.
I sternly demanded to know where the parts were and her reply was overseas.
So I purchased a high end American product and my parts are overseas.
As for the quality of the DEF, I don't buy that as an issue.
In the 32k miles and 900+.- hours i have used multiple manufacturers DEF, as with some POWERSTROKE and CUMMINS users, they have NO issues.
Currently GM is picking up my rental and I am hounding them about my payment!!
I have read and watched WAY to many videos and articles.
Remedies have been as simple as plugging it in to boot the system to complete wiring harness'.
I am aware that none of what I have typed here is in anyway directly helpful to your situation, I just wanted to let you know your not alone.
What I would like you and any other users here to do is, poke around dealerships and look at how many DURAMAX' are parked...
In the past month I have located between 3&5 at various locations.
I had heard that GM stopped producing the DURAMAX for a bit and think they resolved the issue!
I'm going with, NO!
After multiple visits to my dealership with more questions than answers my service rep. hinted around the
control circuits for the DEF pump.
Allegedly it is in the DEF tank and unserviceable and I need a new tank, which is (allegedly) overseas.

I'm going with, CHINE is crippling the US auto industry with faulty products!

!DENALI1

 

Follow up to this thread.

- Traced all the wires, no breaks and have voltage and good ground on everything. Took the truck to a Rep Diesel shop yesterday and we hooked it up to the Snap On code reader machine. We tried and tried to reprogram and relearn the New Sensor that was installed. We were unsuccessful the message we were getting was that the NOX 2 Sensor was not communicating. All other checks came back good. At this point the only thing we can figure out or guess is that the Sensor I bought is not OEM and could be bad or not compatible because it is a non name brand? So i ordered a new Ac Delco sensor and going to change to out again and see if maybe that corrects this whole problem.

I have opened a case with GM as a warranty claim but we will see how that goes.

One thing that was weird is on the way home from the shop the truck went into regen. Once i got home I let the truck idle high and the exhaust temp was very high so i could tell it was in the Regen Cycle. Code still would not clear and truck still in limp mode. 6 Miles left

My only other thought is to do a DPF delete on the truck, i don't really want to due to re sale but that my be my only option

Thanks

 

Follow up to this thread.

- Traced all the wires, no breaks and have voltage and good ground on everything. Took the truck to a Rep Diesel shop yesterday and we hooked it up to the Snap On code reader machine. We tried and tried to reprogram and relearn the New Sensor that was installed. We were unsuccessful the message we were getting was that the NOX 2 Sensor was not communicating. All other checks came back good. At this point the only thing we can figure out or guess is that the Sensor I bought is not OEM and could be bad or not compatible because it is a non name brand? So i ordered a new Ac Delco sensor and going to change to out again and see if maybe that corrects this whole problem.

I have opened a case with GM as a warranty claim but we will see how that goes.

One thing that was weird is on the way home from the shop the truck went into regen. Once i got home I let the truck idle high and the exhaust temp was very high so i could tell it was in the Regen Cycle. Code still would not clear and truck still in limp mode. 6 Miles left

My only other thought is to do a DPF delete on the truck, i don't really want to due to re sale but that my be my only option

Thanks

My suggestion is to take the vehicle to someone that can fix it.. How much time and money do you have?

 

I looked again for new info and what i found is the pins inside the plug to the Nox Sensor should have certain voltage, so i tested each of mine. Plug has 6 wires, Here are the results. Ground good, Power 12.6V, Then 4 other wires on the sensor, 3 of the 4 read between 2.8V - 3.5 V. The 6th Wire reads 1.8 Volts I thought that was weird so i traced it and didn't find any shorts or marks on the wire, that wire goes to the fuel pump driver control module.

I thought I would attempt to provide some information about the system and the wiring that may help you understand a little better.

Attached is the sensor connector pinout (sensor 1 same configuration as sensor 2) and the connections to the sensor bus, between the ECM and the fuel pump driver module. Note the 120 ohm resistor in each of those modules - part of the GMLAN (maybe misnamed by me). If the circuit tests to 60 ohms, that tells you that the circuit is complete, if it tests to 120 ohms, there is a short or open circuit. This arrangement is common on the comm circuits by GM.

 

I have been searching since the first of June for a upstream NOx sensor and was told that they were discontinued, does anyone know how long I can drive it before it starts to go into limp mode. I am in Maryland trying to get back to Texas without having to have it towed.2018 Denali

 

Discontinued? I seriously doubt it. Not available, out of stock, yes. OEM sensors are preferred to aftermarket, but use what you can get. Even from a junkyard if it comes to that.

12718742 GM Nitrogen Oxide Sensor | GM Parts Store Carefully check for the correct part number before ordering.

 

Discontinued? I seriously doubt it. Not available, out of stock, yes. OEM sensors are preferred to aftermarket, but use what you can get. Even from a junkyard if it comes to that.

12718742 GM Nitrogen Oxide Sensor | GM Parts Store Carefully check for the correct part number before ordering.

Discontinued? I seriously doubt it. Not available, out of stock, yes. OEM sensors are preferred to aftermarket, but use what you can get. Even from a junkyard if it comes to that.

12718742 GM Nitrogen Oxide Sensor | GM Parts Store Carefully check for the correct part number before ordering.

Discontinued? I seriously doubt it. Not available, out of stock, yes. OEM sensors are preferred to aftermarket, but use what you can get. Even from a junkyard if it comes to that.

12718742 GM Nitrogen Oxide Sensor | GM Parts Store Carefully check for the correct part number before ordering.

yes, I know the part # well I have searched all over for the part to no avail went to gm parts and they said this part was discontinued until they could find a fix, just wondering how far I could drive before it starts reducing power. I also checked for aftermarket part too and can not get one.

 

GMPARTSSTORE says they have one. Call them

 

u029e is a communication code. terminals 2 and 5 at nox 2 go back to a 120 ohm resistor at the ecm. so if you unplug it and set your volt meter to ohms test across terminals 2 and 5 you should have 120 ohms. if you have power and ground i would check to see if your communication circuit is ok.

 

also if you are buying aftermarket brand nox sensors alot of times your ecm will not communicate with that sensor.

 

Was there ever a resolution to this issue? I have a 2015 that a shop just did a CP3 conversion on and now I have both U029D and U029E code. Didnt have issues before, on has 74,000 miles on it and original GM Nox sensor. Would love to hear what the result was.

 

We are in the same boat.
It is July 7th, 2024 and since June 15, 2024, our 2017 Silverado 2500HD LT 6.6L started throwing OBDII Codes and it was like the entire truck was experiencing a complete melt down. I was reminded of those SCREAMING, LEFT. DEMOCRAT, LBGTQ, FEMINISTS, ECO WARRIORS, etc. when the Trailer Brake Controller started throwing a tantrum. The ALARM sounded at least 50 times in 45 minutes. We were hauling a trailer our a hilly, curvy, Ohio road when it started. I had to take my eyes and mind off driving to find out just what was so SEVERE an issue. Sure, the trailer brakes controller was out while towing a 14,000lbs, 36’, triple slide, 2 bedroom, 5th wheel camper. No brakes and couldn’t even tell if we had any signal lights because there was no safe place to pull over and troubleshot the problem that just WOULDN’T SHUT UP. You’d have thought that the engine had no oil, the transmission was dry, or there were nuclear missiles inbound. But then the real trouble started. SUDDENLY the engine was running like it was missing on half the cylinders too. But I couldn’t read what else was happening to the truck because the ERROR MESSAGES were blocking all of the vital drivers data on the center display. When we got the trailer stopped at a safe location the system continued even after unplugging the pig tail. It continued even after we pulled the trailer brake controller fuse and even the trailer charger fuse. The problem was that Chevy, once again, had FRAUD in mind and wanted to bill me for replacing my cylinder 7 injector (which was not faulty but a $1,000 payday for Chevy). It was once again a wire connector that was too short, connected at an extreme “U” turn angle which caused a $14 wire connector to go bad. Luckily we were less than 50 miles from home when this happened but it was not until we got home and found out it was chafing wires that were grounding and shorting against the frame and bumper. I pulled out a cheap code scanner and it was about to melt. Every sensor, motor, and system was falling apart. A list of 16 codes popped out of the cheap scanner. On the dash the error message refused to go away, “Exhaust Fluid System”, “Reduced to 65, then 55, and next 5mph. We replaced the NOX sensors, the particulate mater sensor, the DEF pump and still the system was throwing codes of failing systems faster than we could diagnose them.

P1050, U0076, U010E, U029D, U029E, U023A, U18A2, P203C, P204C, U029E, P20B9, P1488, P021A, P0097 (which is now down to U023E, ​

That was just the first day. Since then was had an advanced code reading done on the truck which showed 128 codes in almost every system on the truck with the most common being shorts and opens. Upon looking on NTHSA we found that just as many of the codes were associated with KNOWN MANUFACTURER DEFECTS (chafing wire harnesses in most reports), but also included poor manufacturing like the coolant overflow tank that would not permit coolant to drain down from the top tank to the bottom tank causing the sensor to go bad. But then it takes a dark turn where Chevy is FRAUDULENTLY performing repairs on customer vehicles that they NOT needed. After having replaced all of the “defective” items the system still refuses to permit the error code to be reset allowing you to drive normally again and SHAZAM, it is reported by almost every Chevy mechanic too. This code can be “IMPOSSIBLE TO CLEAR.” I joked with one person that Chevy must be hiring Ford people but now I am walking like I just let the proctologist for a brain scan. If Toyota would make a ¾ ton and 1 ton truck most Chevy, Ford and Dodge owners would move to Toyota. Many links that I checked are saying that this is impossible to resolve EVEN by the dealer repair facilities. Some comments are saying the Chevy has had their trucks for months without any resolution. This is outright FRAUD. At this point one GM tech recommended bringing my truck in and letting them do a code scan ($165 CHA CHING), a cab off inspection ($1,500 CHA CHING) so that they can visually inspect all of the wire harnesses and connectors ($80 per hour times 80 hours = $6,400 CHA CHING), only to replace a $150 wire harness or a $14 wire connector that they KNOW is the issue. Sorry Chevy by I am not into (like a ROCK) YARD ART collecting. This is my NOT MADE IN AMERICA truck and I cannot afford a second vehicle being a disabled Veteran.

 

https://static.nhtsa.gov/odi/tsbs/2014/SB-10069277-9133.pdf

 

Since part of this deals with DEF let me jump up on my SOAP BOX. DEF - THE ECO FRIENDLY / SAVE THE PLANET MOVEMENT: Ironically, if you are an ECO WARRIOR / GLOBAL WHINER who PUSHED DEF as an environmentally safe solution you would know that the DEF process does harm to the environment by making DIEsel engines run at 2,500 RPM while CAUSING temperatures of over 600C (GLOBAL WARMING) for 20-90 minutes using anywhere from 4-22 gallons of diesel fuel during the REGEN CLEANING process, while injecting chemical and spitting debris into the air they would stop this nonsense. Now take that figure and consider that just in the United States that there is a estimated 14,486,915 diesel vehicles which have to REGEN at least twice a year we are talking about an estimated 289,738,300 gallons of diesel fuel USED just for REGEN and an estimated 9,657,943 hours of these vehicles generating 600C temperatures. Take any old images of coal trains and you will see that the EARTH LOVED COAL (which diesel is closest too). The grass was THICK and GREEN where the coal ash was deposited along the tracks. WAKE UP! This AGENDA also has created huge maintenance issues for consumers where the dealers want to replace $5,000 of unbroken parts (land fill) because it is easier to HIDE the MANUFACTURER DEFECT than to repair them under recall.

 

At this point Chevy needs to send each sensor with the ENTIRE WIRE HARNESS included. OR maybe they should stop making the wire harnesses with recycled cat/dog food so mice and rats won't want to eat them (this isn't my issue - no animals have eaten my wires). I am finding that putting FREQUENCY GREASE (aka Electrical Contact Grease) has resolved a number of issues. It is almost like they are programming the system to fail by the mile or by the hour on anything post 2012 (just like the NEW CYBER SECURITY SOLUTION does in the 2024 models). At this point I am ready to call my insurance company and tell them YOU DEAL WITH IT. I'm sure their attorneys could get GM to fix their issues. Just wait until you figure out those locations just inside of each state called "WELCOME CENTERS", and "INSPECTION STATIONS" are actually DDR check points.

 

SOLVED my U029E with "Exhaust Fluid Service" and "Reduced Speed". For the past month I have been working on this issue on my 2017 Silverado 2500HD LT 6.6L. Tonight I purchased my 3rd NOX2 (downstream) sensor and IMMEDIATELY EVERYTHING WAS FIXED. So, what happened? Why did the previous 2 NOX sensors NOT work? A clue came from GM Parts Direct as the original part number was listed as "DISCONTINUED". Previously we had purchased 2 numbers matching NOX2 sensors 12676706. So why did these sensors not work when the one see image below immediately worked? CHEVY! They programmed out part number 12676706 from the computer and programmed in 12718676. 12718676 CURED OUR U029E and "Exhaust Fluid Service" and "Reduced Speed" issues. Companies are still selling NOX2 part number 12676706 because it was the original device DO NOT PURCHASE THE DISCONTINUED NOX2 SENSOR 12676706. INSTEAD PURCHASE THE 12718676 PART NUMBER.

 

My brother has a 2017 L5P and last weekend he got the U029E code while we were racing in Michigan's UP. He decided that he would head south because if it limped, we would be closer to home. At 5 miles until 4mph, we found a big truck service center about 60 miles from home. I hooked on to the race trailer and a buddy came with a flatbed for the truck. We changed the downstream NOx sensor and the code cleared on it's own immediately and has been fine since. So, in my only experience with this, the NOx doesn't need to be programmed nor do you need a scanner to clear the code.
I should note that there is another newer part number for the NOx. It is

• GM 12741484

 

Any insight.... I have a 21 sierra with the 3.0l diesel showing these codes. Replaced sensor one on the turbo and nothing. Not sure if its wiring or what. Had new camber pins welded in last Thursday and a new windshield on Friday. Got in it after they replaced the windshield to a CEL and service def and xxx miles till reduced speed. I NEED HELP!!!!! U029D U029E U0076 U010E U02A1 U02A3 U18A2