Hey Guys,
A couple months back I posted on here when my truck threw a code for Coolant Temp Sensor (P01F0). The issue cleared up on it's own for a while, then returned 2 weeks ago. I did confirm the engine was not getting up to proper temp, (only around 160*), but I continued to drive the truck for 4-5 days, (25 mile round-trip, about 50/50 city/highway). I replaced both of the thermostats, which cured the temp problem, but the CEL/MIL did not go off within the next day, and on that 2nd day I fired it up, and was driving when I got 3 rapid chime noises, and a message displayed on the dash for a few seconds, saying "Cleaning Exhaust Filter, Continue Driving". Within about a minute, Display shows "Engine Power Reduced", and basically went into Limp Mode. I was still close to home so I went back, put my scanner on it, and it had thrown 2 new codes: P2471 (EGT #4 Voltage High), and P113A (EGT Sensors #3-4 Not Plausible). Looked at the Live Data, and EGT # 4 (which is at the tail end of the DPF Filter) was reading 1832* on a cold start, while the other 3 EGT's all ranged from 131-166*. Checked the wiring and connections, all good, so I got a new one at Napa, replaced that sensor, and the EGT went immediately back to normal, with warmed-up idle temps around 300-330 just like the other 4. But it still flashed the Cleaning DPF message shortly after startup, and 30 seconds later flashed the Reduced Engine Power message and went into limp mode. By now, a 3rd DTC pops up, P2463 (DPF Soot Accumulation). Then I realized that from the time the first coolant temperature problem popped up 2 months ago, I could not recall the truck going into Regen mode. This makes sense now, since the engine was not getting up to normal operating temp, (so no Regen mode), then the DPF EGT Sensor went whack, so again/still preventing the DPF Regen cleaning. Finally, after a couple of days of short trips around here, all the codes have now cleared themselves except for the P2463 Soot Accumulation. It still does the same thing, on cold or hot start, flashes the Cleaning Diesel Filter message after startup, then 30 seconds later Engine Power Reduced. But it is NOT entering the Regen mode, idle is at standard 640 RPM, and the 4 EGT's are all normal range.
I do not know what it causing it to go into Limp mode, but I am pretty sure it will never be able to get the EGT's hot enough for a regen when it is limiting power to maybe 5% throttle. I even tried clearing the DTC's, and it will turn off the MIL/CEL, but again does the same thing on startup. I even tried to pull a fast one on it, by pulling over on an empty highway (engine at full operating temp), shut it off, then key on, clear codes, immediately start it up and accelerate quickly up to 65-70 MPH, then the engine power limiting kicked at 30 seconds, (actually 34, according to Freeze Frame), just as it has been. Still no regeneration.
I am NOT inclined to put a new DPF on it, and to be honest, I don't think it needs one. My scan tool does not show Soot Load in Grams, it shows Calculated Load %, which hovers around 10-12% at idle, and around 24-36% driving in Limp mode around 2,000 RPM. On my one heavy throttle blast (not power limited), it was at 49%. My scanner does show DPF Back Pressure, and at idle it is very low, (maybe 0.1 PSI). Cruising at 2K RPM in Limp it never goes over 1.37 PSI. I have no idea what the spec is, but something is causing the ECM to keep putting the truck in reduced power / limp mode, and possibly also preventing Regen, (although I think that may be a by-product of the limp mode)?
Does anyone have any suggestions on what data parameters I can look at, to determine why it is limiting power, and/or how I can get this thing to perform a regen? It is almost like a vicious cycle - Soot Accumulation possibly causing limp mode, and in turn limp mode preventing Regen to remove the soot accumulation. Trying to figure out how to break the circle. I believe if I could get it to run the regeneration just once, all would be well again. I have read Dealers can induce a manual / Service Regen, but my local Stealer wants $100 to walk in the door with a Check Engine or Malfunction Indicator on, and another $50-99 to pull and interpret the DTC codes. Which they must do before they will consider performing a Service Regen. I guess I understand, but all told it is sounding like a $300 tab to do something that will take them 5 minutes of effort, plus a few clicks on a GM device and then just wait for a 20 minute routine to complete itself.

Sorry for the darned long post, and will certainly appreciate any tips, advice, or experiences you guys can share.

This message has been edited. Last edited by: FootbrakeJim,

Someone at independent shop with a good scanner should be able to do the same job on a regen. , Just make sure it has enough fuel in it to run at 2800 rpm for about 20 minutes.
This might sound dumb but I have seen a dirty air filter cause no regen. .

quote:

Originally posted by NFC:
Someone at independent shop with a good scanner should be able to do the same job on a regen. , Just make sure it has enough fuel in it to run at 2800 rpm for about 20 minutes.
This might sound dumb but I have seen a dirty air filter cause no regen. .

NFC, thanks for the tip.
I will recheck proper air filter installation, (I replaced it in September, approx 5K miles ago). I did see comments in my research, about K&N air filters causing issues with MAF sensor readings, this is a Wix filter.
I also filled it with fuel 2 days ago, (was half tank), and added another 2.5 gallons of Blue DEF to make sure all related fluids are fresh.

Anyone know what operation cycle requirements need to be satisfied to achieve full Ready status on all the I/M Monitor parameters? (Miles, Days, Hours, Cold Starts, etc)? This is a 2015 truck with 114K on it.
Also, I have heard emissions warranty was extended by GM to 120K miles on some years of Duramax trucks, anyone have info on that?
Thanks again, -Jim.

This should show the warranty here as i understand it.. I texted a friend in Florida with Chevy. Waiting to hear back from him.

https://my.chevrolet.com/home/?sso=false

Sounds like you're going to need a forced regen and very likely an indirect injector replaced.

TD3550, thanks for the link, I haven't visited that site in a couple of years. It lists all the different warranties that applied to my truck, and all are expired, (including emissions), except for one called "Special Coverage 29400". No idea what that is, but is shows good until 120,009 miles, (120K - Why the extra 9 miles?), and Expiration Date of 8/7/2025, (10th anniversary of truck build date).
Deuce 7194, I was wondering about the "9th Injector" possibly being bad, I would imagine among the dozens of sensors on this thing, that one or more of them would detect a malfunction of the exhaust injector and trigger a DTC?
I can say that it did try to do a self Regen twice yesterday - the idle speed kicked up to 800, and I had my scan tool monitoring the 4 EGT sensors, all of them showed temps increasing steadily, so I continued driving, but then the damned power limiting kicked in, the 4 temps slowly dropped, and it bounced out of Regen mode. So yes, it looks like a forced/Service Regen is the next step. You would think the software in the ECM would realize that this truck needs a regen to clear the only fault, and provide a temporary override or delay of the stupid power limit, long enough to give it a chance to Regen and clean the DPF. Almost like this programming "flaw" is intentional - Forcing vehicle owners to visit a dealer and pay for something the truck can and should be able to do on it's own.
I really miss the days when Dealership Parts and Service operations were considered a "Cost of Doing Business", instead of being counted as "Profit Centers"...

I really miss the days when Dealership Parts and Service operations were considered a "Cost of Doing Business", instead of being counted as "Profit Centers"... [/QUOTE]

So a dealership shouldn't make money on service or parts?

quote:

Originally posted by T172JR:
So a dealership shouldn't make money on service or parts?

T172JR, not saying that at all, we live in a nation that values Free Enterprise. Just saying it used to be different, in that the car makers and dealers profit was made off new and used vehicle sales, and supporting those products after the sale (through parts and service) was positioned as more or less a break-even proposition, in order to generate customer brand and dealer loyalty. Those days are long gone, and vehicle costs (including service and parts) have gone through the stratosphere, thanks mostly to organized labor, and also governmental regulations, (which are about to really get ugly, based on the recent presidential and senate election outcomes). I remember walking into the parts counter at a small, rural Chevy dealer in 1978, and buying a front bearing retainer for a Muncie M-21 transmission, for the whopping price of $3.21. Even at that era, the price seemed crazy low for a part that was cast, precision machined and packaged. I asked the counterman if he was sure his retail price was correct. He said "Chevrolet basically tells us to sell parts at cost. They want you to buy another car from them when the time comes".

Jim. As i understand it has been revised. Here includes a PDF.

https://static.nhtsa.gov/odi/t...MC-10135147-9999.pdf

quote:

Originally posted by FootbrakeJim:
I have read Dealers can induce a manual / Service Regen, but my local Stealer wants $100 to walk in the door with a Check Engine or Malfunction Indicator on.

Most dealers only charge a separate diagnostic fee if you have them see what's wrong but then refuse the repair, otherwise they would spend thousands on equipment & labor to diagnose cars for free so people could fix them themselves or bring them to a local garage to fix. You really can't expect them to spend an hour writing up a repair order, bringing your car in the shop, hooking it up to a machine they may have spent $25,000 for and writing up their findings only to make $0.00. I have worked in dealership parts departments for 25 years and worked with many people who have been in this industry a lot longer than me... I'm not sure what the dude in 1978 was smoking & I hate to ruin your nostalgic memories of the good old days but I can tell you that Parts & Service is generally 40-60% of a dealerships revenue and always has been. If you don't believe me, then show me a dealership where the parts & service department isn't roughly twice the size of the showroom!

Jim. incoming PM.

To close the loop on this one, I was able to perform my own Service Regen on the truck, and it is now fine, no MIL, no codes stored, etc.
I still say there is a GM flaw, (or possibly an intentional trick to force a visit to your local Dealer for paid service, that the truck ECM should be smart enough to figure out on it's own).
Any of you who own an "LML" version Duramax truck, (Model years 2011-2016), I highly recommend you purchase the following items (Unless you own a Tech II scan tool). For a total out-of-pocket cost of under $55, (and no need to leave home to get them). This setup let me do things my $160 Innova scan tool would not:

1. Go to the Google Play store, and find an app called Torque Pro, cost is $4.99.
2. Same place, find and buy an app called BiScan for GM. A bit pricey at $29.99, (the developer is an LML owner, he had to do a lot of reverse-engineering to create the app. Worth every penny in my book, it is a plug-in that loads into the Torque Pro app seamlessly, and lets you not only import a huge set of "PID's" to Torque Pro, (parameters that you can monitor live, real-time, while you drive, vehicle specific scan tool, DPF soot load, all 4 EGT displays, EGR temps and activities, Turbo vane angle, TPS, MA, Boost, DPF backpressure, and "see" output of almost any sensor on the truck, etc), but also gives you bi-directional control to command things like a Normal Regen, Service Regen, unlock doors from your phone (if you locked your keys inside, etc). You can set idle speed, several other features.
3. All of this works on your Android phone via Bluetooth. So you need to buy an OBDII Bluetooth Adapter. About the only place I found them for sale is on Amazon. Surprised Summit or even parts store chains don't offer them for sale, (a search of the Autozone, O'Reilly and Advance/Carquest sites gave ZERO results for them). There are many Chinese clones out there, but I can tell you there is one that works perfectly with the Torque Pro app, it is the VGate iCar Pro Bluetooth 3.0 OBD2 Code Reader. $19.99, free delivery to Prime members. Here is a link to it:
iCar Pro BT 3.0 OBD2

Oh, and for you Apple users, (since the iPhone & iPad will not communicate with any of these Bluetooth devices), there are now WiFi OBD2 adapters you can use. You'll need to search for them, make sure they are compatible with Torque Pro.
The BiScan developer is extremely responsive, he got back to me several times very quickly and was super helpful.

Interesting that Apple devices will not connect to the Bluetooth scanners. I have one and had Torque Pro on my Android phone but haven’t tried to scan anything since switching to iPhone within the past year.

Good thing I still have my Samsung and an Android tablet sitting around.

If want want to talk about flawed GM engineering here’s an example too. My wife’s 08 impala she had would self learn the position of each wheel so you knew which tire was going low you just had to put it in a mode and either add air or release air out of each specific tire in an order. My 2014 Silverado you have to have a $100 scan tool to do it, I don’t have the tool and don’t care because I can figure out which one is going low with tire pressure gauge if not visibly low.

I forgot to mention you can also use a laptop / Windows with the WiFi OBD2 adapters.

Using the BiScan tool, I was amazed to see some of the types of data stored in the ECM. Some of the stuff goes back to the build date of the truck. Total number of Regen cycles. Total hours run time, total hours of idle time, Average number of miles between regens, a whole lot of stuff. You can also control parameters for the EGR valve operation, (Which is tempting to play with, since the idea of pumping soot-filled exhaust into the intake tract has always really bugged me).
One other thing of note: I am now convinced the Service Regen may not be a bad thing to do on any truck once in a while, (maybe 1-2x/Year). I believe it cleans the DPF more thoroughly than the routine self-induced normal regen cycle. DPF backpressure is lower now than I've seen it in over 2 years, and MPG has gone up significantly. I've driven the truck over 260 miles in the past 3 days, (mostly highway miles), and the DIC calculated mileage (FWIW) set a new record yesterday for a 50 mile stretch of highway, 26.4 MPG. And my average speed was over 70 MPH. I will calculate the actual fuel consumption rate when I fill it up next, but it still has over half a tank left, usually around 220 miles the gauge is showing half-tank.
I don't know if the Service Regen has any negative effects on the engine, it gradually brings the RPM up to around 2800, (I believe Redline on the DMax is 3,000), and keeps it there for almost 40 minutes, then eases down to a fast idle for about 4-5 minutes to cool things down. I kept the hood open, windows down, and heat cranked up, just to help out the cooling system, but I monitored the actual coolant temp, and it never exceeded the normal operating range of 180-188*
I definitely wouldn't do it with oil & filter in need of changing. EGT's get extremely hot, so don't park it over grass or anything flammable, and it is very loud, as it engages the fan clutch the entire time, and diesel crankcase sounds (plus solid lifters) at 2800 RPM are pretty noisy. If you have irritable neighbors, choose your time and place wisely.

This message has been edited. Last edited by: FootbrakeJim,

Very common occurrence in my work What the automotive call the 9th injector is called the Doser valve in the trucks OR slang. 7th injector.
Common is they get sooted up and have to be cleaned or replaced. Yes exhaust stream can reach 1150F. On average i will do 10 to 12 a month. More common on DD15"s. Restriction high,soot level high.Most class 8 must obtain minn 170-180F. Worse time is in the winter. Can't get the engine temp up when it derates. Like in sub zero or single digit temps.Just terrible working conditions on the side of the road. Glad you got it figured out there Jim.

Kids 14 same code! Taking it in tomorrow.

quote:

Originally posted by stk 758 BP!:
Kids 14 same code! Taking it in tomorrow.

Hopefully they got your boy's truck fixed up at minimal cost. Do not let them convince you that the DPF needs to be replaced. (Very pricey). If there are no other codes stored, and dealer / shop quote is more than $100, I would recommend you try what I did.
I have driven the truck over 1,000 miles since I initiated the Service Regen, and it finally performed a routine Self-Regen at 607 miles after that. Previously the normal interval between regens was around 400 miles. (Which tells me the service regen did do a more thorough job of cleaning the filter). I am curious to see how long before the next automatic one. It kicked in when soot load hit 42 grams, the regen dropped it down to 4 grams.
Fuel consumption still better than before, and noticeably more power & better throttle response (less boost lag) than ever.

Thanks FBJ. His seems to regen quite often.... I am going to do what you did first.

Blue Driver works with Apple.