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NOx Sensor Replacement

164K views 38 replies 13 participants last post by  NYTEAMSTER 
#1 ·
Just wondering if you can replace these sensors yourself or does GM have to do it?

Have not been able to find anything on about doing it so was just curious if you could replace them yourself. Am starting to have problems and suspecting it to be this problem.

Just looking for some general knowledge on the issue above.

Thanks!!!
 
#3 ·
Could question and it would be good to know once the truck is out of warranty. Looks like they run about $130. There's probably some reprogramming to do after a replacement. Let us know if you find out. I have had one replaced. Phillip
 
#4 ·
The mechanical part of replacing the sensors is not a big deal. I can't tell you if there is some sort of recalibration that needs to be done using the tech II.

The 'sensor' includes an approx. 25" harness to a square metal piece that bolts to the truck and has the connector to mate to the truck harness. Presumably there is a small circuit board in the metal piece. The block for the sensor at the back/top of the motor is on the LHS of the firewall. The block for the DPF sensor is frame mounted.

They are about $380 each (in Canada).

If you've still got warranty, u you might as well use it.
 
#5 · (Edited)
It looks like I am going to have to have the NOx sensor replaced. Does anyone know what the going price is?


Well. never mind. I added DEF yesterday and drove about 20 miles with nothing happening. This afternoon I went out to get pizza and the light cleared. Hopefully it really was just some bad DEF.
 
#6 ·
Here is the current problem I am having and is the reason why I asked this question last night when I was on here last.

Went last week to get check engine light checked to see what it is and part guys said it was generic code and one that he did not have in his scanner and also when he ran it through the computer.

Have done some looking around but have not been able to pin point an exact diagnose on what this code is.

Also, before the light came on have been getting Diesel Exhaust Fluid Poor Quality, Please See Owner's Manual.

This light has been going off and the check engine light has been coming on. After awhile the check engine light goes off and I go about three or so days before the DEF light comes on and then the check engine light a few days later.
 
#7 ·
Also, info on truck at this point 2011 with 45,700 miles.

Problem I am going to run into is the dealership around here is open till 5pm M-F (west central Illinois), and starting Tuesday I am working 7 days a week till the 2nd week of October (starting seed corn harvest) and need my truck on a daily basis. Which it has all the tools that I will need. Problem I see happening is that the dealership will not be willing to loan me a loaner truck to use to carry the tool box and other needed equipment.
 
#8 ·
Dealer should be able to schedule you in to minimize downtime. You'll probably lose less time than doing it yourself.

It only takes minutes to read the codes with a techII.

Don't let the technician remove the sensor(s) unless the replacements are in hand.
 
#10 ·
Alright thanks for the help. Need to call dealership and see what they say and go from there.
 
#16 ·
Timmy,

I got the "exhaust fluid quality poor--see owners manual now" message and the DEF light last Friday. On a trip last summer I let the DEF get real low and I had to put 5 gal. in to get the system to reset so it has been 9-10 months since I added any. The book said to add fresh and drive it and it may clear. I added 2.5 gal. and drove about 30 miles with no change. It was showing codes P20EE and P27F. I reset the codes and still had the light so I figured it was off to the dealer today. I took the truck to pick up some pizza last night and the light went out and the codes are clear. I guess that the urea in the tank went bad. I will never let it get that low and never add more that one container at a time again. Hopefully it is fine.
 
#18 ·
Glad the codes cleared and lets hope it was just a hiccup. I never add more than 2.5 gal at a time because I worry about the stuff going bad in the summer heat. It gets hot here in AR. I did add a 2.5 gal jug before I got the 999 warning a few weeks ago. I didn't want to have any issues while on the trip to Gulf Shores......

I am not sure Tim. My guess it you probably need a TechII There are some pretty sophisticated aftermarket scan tools out there... so maybe...
Figured as much.........Those TechII's are $$$$$$

Tim
 
#20 ·
Sarah,

Thanks for the offer of help but the issue cleared with just adding fresh DEF. I hope I won't need the assist but if it comes back I will keep you in mind.
 
#22 ·
My truck had message come on saying poor def quality and now it's throwing codes like p20ee and p207f I have had nothing but problems with exhaust emission since I have bought the truck about 4 weeks ago I have been in the shop every week once or twice a week seriously considering doing deletes
 
#23 ·
Finally got my taken care of last week and they replaced Nox sensor and just tonight on the way to work the light for poor def just came up; has been a week to the day that i had the sensor replaced.

Im with you on the deletes. Why keep making a headache for yourself when you can just get rid of it? Makes no sense to rob trucks of the MPG potential to save a few pollution particles. I think something needs to be done because it makes no sense financialy.
 
#25 ·
@bfamilycattle ya my dealer blew me off saying they are done with me telling me to go somewhere else with my problems. And my truck is a 2011 with 70000 miles they have checked def quality and replaced nox sensor checked codes did the burn and all the necessary thing and they just flash system and say give it a shot sick of there shit
 
#26 ·
Yeah i feel you there. I have had it throw the p20ee code for over 6+ months and then i decided to finally have it looked at since i knew warranty would pay for it. They didnt like it when I told them what the problem was and they just blew me off that i didnt know what i was talking about. Then they came back and said i was right, well no shit.

The poor def light came on last night on the way to work last night and then on the way home this morning it went out but check engine light never came on like it did before the NOx sensor was replaced.

I would keep taking it to them, its there problem until the warranty is up.
 
#28 ·
Keep us posted on what happens. Hope my problems are behind me but I doubt it. This whole emissions BS is starting to be pain. All so we can save a few parts per million air cells and make us buy more fuel due to restricted MPG cause of the damn emissions.

Good luck!!
 
#30 ·
Did it come with 12 month/12, 000 mile bumper to bumper warranty?? Usually does if it was considered a GM certified vehicle.

Should be covered under that if you received it.
 
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