Ok so got fuel this morning drive 2 miles and the check engine light comes on. Turn her off and think it is the gas cap. No luck. Turn on off the key 3 times still stays on. Go to the dealer and they say it is a NOX sensor below min threshold... anyone ever heard of this?

 

what was the code that the truck flashed? I've never heard of a nox sensor-where is it?

 

you know the guy did not say he just said emission NOx sensor below threshold.

 

the nox sensor code has been frequent it is a p2000 probably your getting the best luck so far that i have had is to clean the oxygen sensors not with any chemical but with just compressed air and a dry cloth. reset the code and try. if it persists engineering gets involved usually caused by excessive idle or if you have an add on chip. not trying to know knock chips but also a real common cause for check engine lights on these. another thing is to make sure that the engine ecm is up to date as far as updating of the software. nox is a thing that the gov is making all the diesels control seeing as soot and nox are a high output of diesel engines due to the fuel for soot and the high combustion and exhaust temps create excessive nox pollution let me know if it is any help or if can help more

 

Thanks but says I am below the NOx threshold. No chip and I have had the update on the truck to have the High Idle. Don't really idle except for a few minutes in teh winter when cold out, but then it goes into its own high idle automatically.

Not sure about the ecm updated but just bought the truck in December. We will see what they say.

 

dealer just called and said the system needed an update we will see.

 

So there is an actual nox sensor? I thought it was an adsorber which just absorbs it into the oxidation catalyst in return is pretty much burnt off. If the catalyst got clogged or is getting clogged the pressure lines tied into the exhaust sensed this and thats what triggered the p2000 nox adsorber efficiency below threshhold code- getting clogged and reducing pressure.

 

I am assuming there is a Nox sensor. How or why does it happen?

 

I have tried to find it but can't figure out where it is, anyone?

 

there really is no true nox sensor but a factor determine by the ecm knowing what engine temp is exhaust temp and the oxygen sensor status along with the backpressure sensors all factoring into his there is no true sensor. but the nox sensor threshold is mainly due to the backpressure readings from what we here a the dealership have been told. and when you get the pcm update make sure they update your cluster also that is another part of the bulletin that i forgot to say that bulletin is 11-03-07 i think from memory hope this helped a little more thanks guys