Without the code numbers, we cannot help...but...
the service exhaust fluid message is typically a skewed NoX sensor. But, it can also be a bad DEF pump or heater.
The indirect injector helps with DPF regeneration.
The cylinder balance rates may point to injector (one of the 8, not the indirect one).
The "smoke" part is perplexing, though. What color is it? Does it smoke at startup?


IMHO, I say run. Run away. I've been here a long time, and I can't recall ever seeing a DOC being changed.

Again, you've supplied nowhere near enough info to point us the right way.

 

I can get all the codes tomorrow. The truck doesnt smoke on startup, only driving at speed. The smoke appears whitish in color. My thought was to pull the doc off and try to hot pressure wash it backwards. If its already junk, it cant possibly hurt it. If its just plugged it might take care of the issue...🤷‍♂️

 

Be sure to take a minute and update your signature with the vehicle info and list all mods.
This can help you faster and save some time

 

I got all the codes from the dealership today. here goes:

po266 Cyl 2 balance system
po278 Cyl6 balance system
po284 Cyl 8 balance system
po420 catalyst system efficiency below threshold low temp
po673 cyl 3 glow plug open
p2033 exhaust gas temperature sensor circuit high bank 1 sensor 2
p24A0 Closed loop diesel particulate filter regeneration control at limit Low temperature

 

Fixing the P2033 (replacing the EGT sensor or the damaged wiring) should fix the P0420 & P24A0, especially since the 9th injector was changed. That code (P2033) "circuit high" is either a broken wire or a broken sensor. It certainly won't regeneration, forced or passive, if the sensor is offline.

The 1st three codes may require a little more evaluation, but, not until the P2033 is addressed.

Nothing there points to DOC or DPF element issues.

 

Thanks for your reply. The dealer has changed the 9th injector and bad egt sensor. After 6 regens its still smoking going down the road. They are claiming bad cat and are saying the combustion in the pipe is happening too late creating the smoke. I guess the last egt sensor showed the hottest reading and they say it should be hotter further up the pipe.

 

Little Update. I got fed up with the stealership because they refused to guarantee that the repairs would work for repairing of the catalyst 0420 code. I decided to take the truck back and on the ride home the truck let out one VERY small short puff of blue smoke. In their words the truck was basically leaving a smoke screen everywhere they went causing cars to pull off the road. That was absolutely not the case on my ride back. Im going to remove the cat and try to get in there with a borescope to see if the face of it is blocked up. If so i may try to hot pressure wash the cat against the exhaust flow and blow it dry. I have sourced a cat if needed , gm genuine from a dealer for 1346.12....a far cry from the 2200 plus install that my dealer wanted. I guess it really pays to purchase 20 vehicles there over the last 25 years.....

 

P2033 say the circuit is OPEN on the exhaust temperature sensor BEFORE the DPF. That sensor has NO way of KNOWING whether the DPF or DOC is functioning.

OPEN is either a damaged harness or plug, or a failed sensor.

 

That code has been taken care of. The 2nd sensor was dead and has been replaced. The only code i currently have is po420, catalyst efficiency low.

 

Has the DEF injector been tested? Which is NOT the 9th injector. DEF can crystallize on the injector nozzle and lead to that code.

 

Thats a great question. Not one time did the dealer mention that this could be an issue. Ill have the truck on my lift later today. I also have a snap on solus scan tool, should i remove it and do a visual on it or command it on with the scan tool?

 

Welp. Cat is definitely junk...it came out in a pile. Pics attached as well as pic of def injector.

 

And on todays episode of you cant beleive this ****...... Truck was into the dealer for 9th injector, egt sensor and they hit me up for an engine air filter. 1600 bucks to change the 9th injector and air filter, egt was warrantied. I decide im doing the cat replacement myself, so i take the truck home, find and purchase a cat 600 bucks cheaper at a dealer 3 miles away. The attached pictures show the condition of the threads on the 1 week old EGT sensor and the galled threads in the old cat pipe. Upon calling the dealer regarding the new/ f*cked sensor the shop foreman told me " Those threads are designed so that you really need to JAM it in the pipe so that the vibration doesnt make it fall out going down the road". Mind you a quick thread chase and some anti seize would have solved this issue. I demand that they replace the sensor with a new one so i dont damage the threads in my new cat pipe to which im told " Sorry the job wasnt done here, we cant replace that sensor under warranty".Well, " yes yes the threads WERE destroyed upon install by your hack mechanic". To which im told " sorry, you are going to have to take this up with GM". Consider it done. Friends, dont let friends do anything with CENTRAL CHEVROLET WEST SPRINGFIELD, MA. rant over!!

 

And on todays episode of you cant beleive this ****...... Truck was into the dealer for 9th injector, egt sensor and they hit me up for an engine air filter. 1600 bucks to change the 9th injector and air filter, egt was warrantied. I decide im doing the cat replacement myself, so i take the truck home, find and purchase a cat 600 bucks cheaper at a dealer 3 miles away. The attached pictures show the condition of the threads on the 1 week old EGT sensor and the galled threads in the old cat pipe. Upon calling the dealer regarding the new/ f*cked sensor the shop foreman told me " Those threads are designed so that you really need to JAM it in the pipe so that the vibration doesnt make it fall out going down the road". Mind you a quick thread chase and some anti seize would have solved this issue. I demand that they replace the sensor with a new one so i dont damage the threads in my new cat pipe to which im told " Sorry the job wasnt done here, we cant replace that sensor under warranty".Well, " yes yes the threads WERE destroyed upon install by your hack mechanic". To which im told " sorry, you are going to have to take this up with GM". Consider it done. Friends, dont let friends do anything with CENTRAL CHEVROLET WEST SPRINGFIELD, MA. rant over!!

As the owner of the business ive been wrenching on trucks, equipment, etc for 25 years. This is just another checkmark in the column as to why dealers suck and you cant trust them.

 

Damn it man... I'm impressed you stayed with this.

 

I've never ever ever had any dealer fix anything except their profits If anything I've had more issues after I've left. Truly sad with how much we spend on these trucks. They'll truly "service" you after the sale. I got the contaminates def story stuck in SLC for days limited to 4 mph after filled from dealer in OK a few days before. I only care who will get me the best price for what I want and will travel many states to get it at this point.