Dreaded DEF issues

[Sierra66]

I am currently in a 2012 GMC 2500 HD DURAMAX. I bought it with 80k miles and have put on about 8k. Just yesterday the "check def system" light came on. I was parked at a somewhat steep angle at the time. I drove it and the light went off but the CEL stayed on. I added some juice but the light is still on.

I am am really hoping it's not the NO2 sensors as we are pulling to Clearwater Fl (9hrs) for a week on Sunday. It will be under the extended warranty I got but I don't want the headache so close to a long trip.

Someone have experience with this?

 

[danemayer]

I think our 2011 GMC had a NO2 sensor failure. Took about 2 hours at the dealer. We also had some failures on the Reductant Tank Temperature Sensor. The reductant tank had to be replaced. Took 3 or 4 hours best I remember.

 

[cookie]

I am am really hoping it's not the NO2 sensors as we are pulling to Clearwater Fl (9hrs) for a week on Sunday. It will be under the extended warranty I got but I don't want the headache so close to a long trip.

Someone have experience with this?

Probably better to deal with the headache now rather than on the side of the road next week.
If you think the CEL came on because of the DEF being too low you might want to check what that code really is.
If you don't have a OBDII scan tool you can have it checked and cleared at an Auto Zone store.

Peace
Dave

 

[FLOYD PHILBROOK]

I had same problem on my 2011 3500 HD and they had to replace the DEF tank. Floyd

 

[Nabo]

WOW Jonathan - sorry to hear about the truck. Hope it's a simple fix. We also will be in FL next week, leaving Friday, over nighting in Tallahassee area, then on down to our rv community in Davenport. We have a family wedding in Mt Dora so life will be busy.

 

[lynndiwagoner]

Almost 100% sure it's the NO2 sensor. GM has extended the warranty for them. I had the same symptoms....wasn't DEF fluid.

 

[GOTTOYS]

Trying to have your truck diagnosed over the internet will result in a bunch of guesses but no real cure. Spend a couple dollars to bring it to a dealer and eliminate the guesswork....There isn't anyone here that tell you what the absolute fix is and you could spend hundreds just shotgunning parts at it and not find the cure. There are numerous reasons why the CEL can come on. The O2 sensors are only one of them. Maybe they can point you in the right direction but that is about all...Good luck..Don

 

[Gary521]

I think there is an extended warranty on that system.

 

[MTPockets]

I have a Ford, but one time I added just one gallon DEF and the light stayed on. Later I filled it and now, whenever I need DEF I always fill it Instead of partial.. No further problems...

 

[Terry H]

If you have and subscribe to Onstar, just press the Onstar button when the engine is running, and ask them to run a diagnostic. Then they can tell you why the CEL is on.

 

[Sierra66]

Took it my Diesel guy and we checked the codes, two came back:

p202e - inductant injector

p128e - fuel rail pressure

I had him erase them so see if they'd come back. I drove for an hour or so and nothing returned. I put in 3.5g of Blue DEF. She is running like a champ. I am crossing my fingers for a just a quirk reading. My guy and the dealer is to busy to even look at it. Leaving Sat for a long trip.

Next summer I will not worry about DEF ever again.

 

["Hi-Viz" Bill]

Newbies Here !! ****, I hate acronymns .. Help !! ... DEF, CEL, NO2 & OBDII ??? What the ????

Thank you in advance !!

 

[NHCelt]

Yep...lots of experience, unfortunately. Nox sensors, reductant tank sensors etc. Most of the system has an extended warranty. You are within the window. You want to resolve this before a trip as your engine with eventually go into limp mode. I guess it depends on how far you will be towing.

I am currently in a 2012 GMC 2500 HD DURAMAX. I bought it with 80k miles and have put on about 8k. Just yesterday the "check def system" light came on. I was parked at a somewhat steep angle at the time. I drove it and the light went off but the CEL stayed on. I added some juice but the light is still on.

I am am really hoping it's not the NO2 sensors as we are pulling to Clearwater Fl (9hrs) for a week on Sunday. It will be under the extended warranty I got but I don't want the headache so close to a long trip.

Someone have experience with this?

- - - Updated - - -

......and sorry, but fortunately no experience with the fuel pressure issue. Check www.duramaxforum.com.

- - - Updated - - -

Bill n Sue, you are lucky, but here you go;

DEF is diesel exhaust fluid
CEL is check engine light
NO2 is the nitrogen oxide sensor, also called NOX1 or NOX2 as there are 2 of them.
OBD is on board diagnostics

With good fortune, you will never have to experience the joys of diesel emissions and/or injector issues. )

 

[danemayer]

Newbies Here !! ****, I hate acronymns .. Help !! ... DEF, CEL, NO2 & OBDII ??? What the ????

Thank you in advance !!

DEF = Diesel Exhaust Fluid (Ford, GM, RAM diesel engine exhaust systems use this to control emissions starting with 2011 models on Ford and GM, 2012 with RAM). DEF is added by the owner as needed. After warning you for xxx miles, truck will go into a "limp" mode if you run out, or in certain cases where the emissions system is failing. Do not ignore the warnings.
CEL = Check Engine Light - on the dashboard driver display to let you know something is wrong.
NO2 = Nitrogen diOxide, measured to determine how well parts of the emissions system are working.
OBDII = On-Board Diagnostics System, stores diagnostic codes to support service work. An inexpensive code reader will let you read the code that causes the Check Engine Light. Then you can look up the meaning of the code and find out more about what's wrong. Some auto parts stores will read the code for you at no charge.

 

[JohnD]

Next summer I will not worry about DEF ever again.

Are you switching to a gasser?

 

[porthole]

Newbies Here !! ****, I hate acronymns .. Help !! ... DEF, CEL, NO2 & OBDII ??? What the ????

Thank you in advance !!

It is NOX, not NO2, nitrogen oxide, also sometimes referred to as "oxides of nitrogen".
NOX is one of the resulting "pollutants" from the internal combustion engine.

DEF and catalytic converters are used to reduce NOX emissions.

- - - Updated - - -

Took it my Diesel guy and we checked the codes, two came back:

p202e - inductant injector

p128e - fuel rail pressure

I had him erase them so see if they'd come back. I drove for an hour or so and nothing returned. I put in 3.5g of Blue DEF. She is running like a champ. I am crossing my fingers for a just a quirk reading. My guy and the dealer is to busy to even look at it. Leaving Sat for a long trip.

Next summer I will not worry about DEF ever again.

Most automotive systems, if you run your DEF level down low enough to bring on a check engine light, just adding DEF will not clear the code.
If you run DEF low enough, you will put the vehicle into a reduced power output mode, and one way to achieve that is to reduce the fuel pressure.
So, having a cause for the first can lead to the second.