2012 LML. Truck has always run on the cool side, 175-180, and last month I got a low coolant temp DTC, temps had been around 160. At the same time, regen would come on at around 16 grams of soot instead of 44. I had the t-stats replaced and temp is up to 190, but, regen is still being picky. The last regen happened at 28 grams. I assume it’ll get better, but, is there anything I can do to help
Low coolant temp= clogged dpf ?
- Thread starter xxiiiliv
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regeneration occurs from two perimeters. back pressure measured by a differential pressure sensor and miles. since you are reporting the regeneration happening too often then it's likely back pressure causing it.
it's possible you have a bad differential pressure sensor but it would seem more likely it is seeing too high of pressure. use your scanner and see how much ash, soot and pressure it is seeing. you can try a service regen but if ash is too high that won't do anything to help. a replacement or cleaning service will be required.
it's possible you have a bad differential pressure sensor but it would seem more likely it is seeing too high of pressure. use your scanner and see how much ash, soot and pressure it is seeing. you can try a service regen but if ash is too high that won't do anything to help. a replacement or cleaning service will be required.
I’m by no means a mechanic, and you seem knowledgeable, so here’s my theory. Is it possible that having low coolant temp, low enough to cause a code, could cause the exhaust to be cooler than normal and coat the dpf with maybe more oily ick? At 85k miles, I’m hoping that’s the case. If that seems reasonable, would a manual regen, or two, make sense ?
at the temperature you report, it is unlikely. plus the ECM knows what temp the engine is and has and exhaust temperature sensor so it can calculate all the soot parameters. things that will throw it off is not using low ash oils or not using ULSD.
you say it is regenerating at 16 grams instead of the usual 44. either that means its making more soot then it thinks or there is a mechanical issue
give a manual regen a try. it won't hurt anything so it's worth a shot
you say it is regenerating at 16 grams instead of the usual 44. either that means its making more soot then it thinks or there is a mechanical issue
give a manual regen a try. it won't hurt anything so it's worth a shot
Scan your regen temps and make sure that egt#2 is going over 1100 degrees. If it is not you need to replace 9th injector. My truck went thru constant regens when the 9th injector starting acting up. It will eventually pop a p0420 code for catalyst performance.
Thanks for that. I actually set up my cts2 to show all 4, but wasn’t sure what the temps should be
Egt #1 should be around 700
Egt #2 1100
Egt #3 1050
Egt #4 1050
Those are mimiunm numbers, if they aren't at that temp or higher your 9th injector is the cause.
Egt #2 1100
Egt #3 1050
Egt #4 1050
Those are mimiunm numbers, if they aren't at that temp or higher your 9th injector is the cause.
Those are all good temps. I'd watch the differential pressure sensor and research what it's normal range is.
Yes. It was in the 1200 degree range the whole time.
I did some research on the pressure differential. It seems time and fuel used are parameters to start regen as well.
So, maybe it’s my fault. I’m retired, don’t do much long distance driving anymore, and to maybe compound the issue, I’m having an ongoing maf code, even after replacing the sensor. Could this maf(or maybe intake leak?) be causing a problem? Remember, I’m no mechanic and am trying to not just fix this, but to understand as well. I appreciate your help
Yes, the maf will effect fueling tables and cause regeneration issues. You running a K&N filter?
Heck egr function as well and turbo vane position desired vs actual. If those are off it can cause a maf reading issue and cause premature regeneration as well. Egr systems cause more DPF issues than any other single item.
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No on the k&n. I have a Banks but with the dry filter. As far as having it worked on, this isn’t necessarily a diesel only problem, am I right? Any mechanic could diagnose this I assume
I didn’t know exhaust leaks could affect this. Over the past few months, the truck has sounded more “diesely”, if that’s a word. As a Denali it’s alway been super quiet, now it’s a bit louder, more clatter, and for a moment at startup, sounds like a pail full of rocks
That, my friend, is way beyond my pay grade
. Is there an English version of what you just said ?