# Sticky  Pre-Regen - Diesel Owners Read This - It can save you a trip to the dealer



## boraz (Aug 29, 2013)

i thought you said you had to interupt the regen 3x to get the cel

cuz that would be insanely retarded to get a cel for one interruption when the driver doesnt even know theyre interrupting something.


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## diesel (Jun 8, 2013)

boraz said:


> i thought you said you had to interupt the regen 3x to get the cel


No - I said I have interrupted it (at least) 3 times with no ill effect. As long as the regen is fully in progress and/or not restarted, but not in the "Pre-regen" status, you are fine. Thanks for asking about that - it's a very good point.


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## GlennGlenn (Nov 27, 2015)

boraz said:


> i thought you said you had to interupt the regen 3x to get the cel
> 
> cuz that would be insanely retarded to get a cel for one interruption when the driver doesnt even know theyre interrupting something.





diesel said:


> No - I said I have interrupted it (at least) 3 times with no ill effect. As long as the regen is fully in progress and/or not restarted, but not in the "Pre-regen" status, you are fine. Thanks for asking about that - it's a very good point.



I just went went through my 1st Regen today, but @*diesel* is correct, there appears to be a "pre-Regen" that lasts for about a minute where the MAP drops below 14 on the Scan Gauge ( at least mine did) before the actual Regen starts ( #1 on my Scan Gauge 2) . This could be the point at which the DPF is getting flooded with fuel and the the DPF is heating up because once the actual Regen starts ( #1 in the gauge) , the Soot Mass starts to drop pretty quickly.


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## DslGate (Jun 29, 2016)

GlennGlenn said:


> I just went went through my 1st Regen today, but @*diesel* is correct, there appears to be a "pre-Regen" that lasts for about a minute where the MAP drops below 14 on the Scan Gauge ( at least mine did) before the actual Regen starts ( #1 on my Scan Gauge 2) . This could be the point at which the DPF is getting flooded with fuel and the the DPF is heating up because once the actual Regen starts ( #1 in the gauge) , the Soot Mass starts to drop pretty quickly.



Bump for for update to this thread: Since I @GlennGlenn get the frequent regens at less than 60 miles between regens since firmware reflash at dealer two months ago, I've become somewhat "quite" familiar with regens, seeing two-three a day. Dealer says this is normal and to be expected. 

Just before a regen, you will see the Map go below / less than 14 on the SC2. This is the period when you do not want to turn off your CTD. It's not in pre-regen long, perhaps two minutes or less, but it is setting the system up for the actual regen which is indicated on the SC2 as #1. If you interrupt the pre-regen , you'll get a #3 on the sc2 and this is not good. Interrupting the #1 is fine as the car will just start regen mode once it gets to temp. You do not want to unterript the preregen that is just before the SC2 goes to #1.


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## diesel (Jun 8, 2013)

DslGate said:


> Bump for for update to this thread: Since I @*GlennGlenn* get the frequent regens at less than 60 miles between regens since firmware reflash at dealer two months ago, I've become somewhat "quite" familiar with regens, seeing two-three a day. Dealer says this is normal and to be expected.
> 
> Just before a regen, you will see the Map go below / less than 14 on the SC2. This is the period when you do not want to turn off your CTD. It's not in pre-regen long, perhaps two minutes or less, but it is setting the system up for the actual regen which is indicated on the SC2 as #1. If you interrupt the pre-regen , you'll get a #3 on the sc2 and this is not good. Interrupting the #1 is fine as the car will just start regen mode once it gets to temp. You do not want to unterript the preregen that is just before the SC2 goes to #1.


It's during this 2 minute period that the "keep driving" message should come on. Maybe they will address this on the new one.


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## DslGate (Jun 29, 2016)

@diesel , it appears that from my DIC and the Scan Gauge 2 that during the pre-regen period , two things are happening: 1. The DPF is at temp or getting to temp in anticipation of a regen and 2. The fuel system is dumping fuel into dpf for ignition and burn off of soot. This is illustrated by the MAP going below 14 for at least in my case about 1-2 minutes and The DIC showing less than 99 mpg when you're OFF the throttle ( illustrating that there is fuel being dumped into the DPF and thus your car is using fuel / dumping fuel into dpf while off the throttle). Interestingly, I also observed that mine will not do any regen or go into regen if the rpms are lower than 1500. I even tried to see if regen would occur in neutral and it would not. 

Regen or pre-regen will not occur IF the vehicle is not up to normal operating temp, which for me is just below or just /before the half-way point on the engine temp gauge. If I start the car and soot is at 22 Soot Mass , the pre-regen and regen will not start until the car temp is near the 1/2 hash mark on the engine temp gauge.


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## papajo222 (Sep 8, 2016)

I appreciate the information guys.

I am at 96k and actually had my DEF pump fail but was unable to replace it immediately and drove about 400 miles (code P21 DD). During that time, I picked up a P2463 code and I was hoping that after replacing the DEF fluid pump I would be able to run enough DEF through to clean my filter back up.

Unfortunately, I am now about 250 miles since replacing the pump and I still have a P2463 code and will likely have to replace the DPF sensor. I am unsure if I am going to replace this myself or take it to the dealership because I don't know if they are going to need to manually cycle the fluid afterwards or not.


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## diesel (Jun 8, 2013)

DslGate said:


> @*diesel* , it appears that from my DIC and the Scan Gauge 2 that during the pre-regen period , two things are happening: 1. The DPF is at temp or getting to temp in anticipation of a regen and 2. The fuel system is dumping fuel into dpf for ignition and burn off of soot. This is illustrated by the MAP going below 14 for at least in my case about 1-2 minutes and The DIC showing less than 99 mpg when you're OFF the throttle ( illustrating that there is fuel being dumped into the DPF and thus your car is using fuel / dumping fuel into dpf while off the throttle). Interestingly, I also observed that mine will not do any regen or go into regen if the rpms are lower than 1500. I even tried to see if regen would occur in neutral and it would not.
> 
> Regen or pre-regen will not occur IF the vehicle is not up to normal operating temp, which for me is just below or just /before the half-way point on the engine temp gauge. If I start the car and soot is at 22 Soot Mass , the pre-regen and regen will not start until the car temp is near the 1/2 hash mark on the engine temp gauge.


I've observed similar behavior, however you can do a regen without driving, i.e. in neutral 

http://www.cruzetalk.com/forum/201-...-discussion/132874-regen-without-driving.html





papajo222 said:


> I appreciate the information guys.
> 
> I am at 96k and actually had my DEF pump fail but was unable to replace it immediately and drove about 400 miles (code P21 DD). During that time, I picked up a P2463 code and I was hoping that after replacing the DEF fluid pump I would be able to run enough DEF through to clean my filter back up.
> 
> Unfortunately, I am now about 250 miles since replacing the pump and I still have a P2463 code and will likely have to replace the DPF sensor. I am unsure if I am going to replace this myself or take it to the dealership because I don't know if they are going to need to manually cycle the fluid afterwards or not.


Sounds like you need a manual regen. Not related to the heater issue. Coincidental. You most likely do not need a sensor replacement. (This is assuming I am correct in assuming that P2463 is the high soot accumulation in the DPF)


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## papajo222 (Sep 8, 2016)

You're right @diesel, it is the high soot accumulation. I decided to buy and replace the sensor myself. I'll try the manual Regen first though. I am hoping to avoid the dealers but if it doesn't correct, I will go get the computer work done.

I think I've driven about 500 miles in reduced engine power mode so I am beginning to worry about whether I am going to begin getting restrictions on speed soon. Haha keeping my fingers crossed.

Thanks again everyone!


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## boraz (Aug 29, 2013)

papajo222 said:


> You're right @*diesel*, it is the high soot accumulation. I decided to buy and replace the sensor myself. I'll try the manual Regen first though. I am hoping to avoid the dealers but if it doesn't correct, I will go get the computer work done.
> 
> I think I've driven about 500 miles in reduced engine power mode so I am beginning to worry about whether I am going to begin getting restrictions on speed soon. Haha keeping my fingers crossed.
> 
> Thanks again everyone!


more of gambler than me


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## jddcruze (Jun 30, 2015)

Bought in late June 2015,now have 7135 miles on it.
Have averaged 42 mpg.
Don't know if it has regenerated or not.
All I get is that the fluid is good.
My question is
How do I tell if it has or is going to regenerate? 

Don at 85 yrs old

Didn't want to reply but ask a quesion


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## diesel (Jun 8, 2013)

papajo222 said:


> You're right @*diesel*, it is the high soot accumulation. I decided to buy and replace the sensor myself. I'll try the manual Regen first though. I am hoping to avoid the dealers but if it doesn't correct, I will go get the computer work done.
> 
> I think I've driven about 500 miles in reduced engine power mode so I am beginning to worry about whether I am going to begin getting restrictions on speed soon. Haha keeping my fingers crossed.
> 
> Thanks again everyone!


I would not worry about the speed restriction as much as ruining the DPF!! Too much soot form ignoring the code= no longer able to manually regen = new DPF required



jddcruze said:


> Bought in late June 2015,now have 7135 miles on it.
> Have averaged 42 mpg.
> Don't know if it has regenerated or not.
> All I get is that the fluid is good.
> ...


Hi Don, welcome to the forum. Without a Scangauge, there's really no certain way to tell. You can tell if you interrupted a regen because your fans will stay on after you shut the car off nad it will smell like melting plastic. That's the only surefire way to know your car is doing a regen. Or, of course, being unlucky enough to shut your car off during the pre-regen I mentioned.


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## LulzT1 (Aug 24, 2015)

Noticed something interesting today..

On my way to work I completed 99% of a regen before turning the car off, was at 5grams. After work I stopped for fuel maybe 10 mins into my trip which was enough to get up to operating temp and resume a regen (RGN = 1). I turned the car off again during the regen at 4grams. When I started the car and immediately noticed the soot jumped to 8grams! So it seems it doesn't necessarily have to be in a "pre-regen" mode for the soot to jump as I clearly burned off a gram and the SC reported active regen. Luckily I was far enough away from the max before a manual regen.

Wish I could have gotten that on video ... Guess I'll be watching more closely if/when I interrupt a regen.


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## diesel (Jun 8, 2013)

LulzT1 said:


> Noticed something interesting today..
> 
> On my way to work I completed 99% of a regen before turning the car off, was at 5grams. After work I stopped for fuel maybe 10 mins into my trip which was enough to get up to operating temp and resume a regen (RGN = 1). I turned the car off again during the regen at 4grams. When I started the car and immediately noticed the soot jumped to 8grams! So it seems it doesn't necessarily have to be in a "pre-regen" mode for the soot to jump as I clearly burned off a gram and the SC reported active regen. Luckily I was far enough away from the max before a manual regen.
> 
> Wish I could have gotten that on video ... Guess I'll be watching more closely if/when I interrupt a regen.


Thanks for reporting this. I will add that I've seen 8 grams happen pretty quickly after i complete a regen at 3 grams.


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## Aussie (Sep 16, 2012)

This may not be of any use, but in my Australian CTD when the car is in regen it idles 100rpm higher when stopped and in drive. I have the keep driving light in mine and it only came on for the second time since 2012 last week, so the regen is fairly invisible most of the time.


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## BDCCruze (Jul 12, 2017)

Aussie said:


> This may not be of any use, but in my Australian CTD when the car is in regen it idles 100rpm higher when stopped and in drive. I have the keep driving light in mine and it only came on for the second time since 2012 last week, so the regen is fairly invisible most of the time.


I've been wondering that myself. I've had mine since October 16 and put about 40k on it. I have not yet seen the DPF DIC warning. I do about 100 miles a day on the freeway though, but I was off work two weeks and figured I would see it while driving around town. Never did pop up.


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## Aussie (Sep 16, 2012)

BDCCruze said:


> I've been wondering that myself. I've had mine since October 16 and put about 40k on it. I have not yet seen the DPF lamp. I do about 100 miles a day on the freeway though, but I was off work two weeks and figured I would see it while driving around town. Never did pop up.


90+% of my driving is in city streets and as I said the light has only come on twice. I just went to a freer road and kept it in a lower gear till the light went out. It took about 10-15 minutes.


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## boraz (Aug 29, 2013)

BDCCruze said:


> I've been wondering that myself. I've had mine since October 16 and put about 40k on it. I have not yet seen the DPF lamp. I do about 100 miles a day on the freeway though, but I was off work two weeks and figured I would see it while driving around town. Never did pop up.


youre quoting a person that drives a completely different car than yours

him posting aboot a f150 would be as helpful as posting aboot his car in relation to yours.

your car does not have a dpf lamp, thats why youve never seen it.


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## Aussie (Sep 16, 2012)

There must be some sort of warning that you need to keep driving, surely? It makes no sense to just let the DPF get blocked without letting the driver know.


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## boraz (Aug 29, 2013)

Aussie said:


> There must be some sort of warning that you need to keep driving, surely? It makes no sense to just let the DPF get blocked without letting the driver know.


there is a keep driving msg possible on the DIC if conditions warrant it.

78,000 miles here, have never seen it.


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## BDCCruze (Jul 12, 2017)

boraz said:


> youre quoting a person that drives a completely different car than yours
> 
> him posting aboot a f150 would be as helpful as posting aboot his car in relation to yours.
> 
> your car does not have a dpf lamp, thats why youve never seen it.


I'm talking about the DIC message to continue driving. I confused it with the DEF warning lamp. I'll edit my original post.


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## boraz (Aug 29, 2013)

BDCCruze said:


> I'm talking about the DIC message to continue driving. I confused it with the DEF warning lamp. I'll edit my original post.


10-4

car is designed to hide the regen process from the driver

if the car is operating properly you wont notice it.

many track it with a scangauge2, but not necessary.


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## sailurman (Sep 29, 2016)

97K and never seen it.


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## MRO1791 (Sep 2, 2016)

Aussie said:


> There must be some sort of warning that you need to keep driving, surely? It makes no sense to just let the DPF get blocked without letting the driver know.


We don't get warning lights for a normal regen event.. this would be too much information for too many people here, thus we don't get it. The warning message to keep driving will only display in rather unusual cases where the soot levels have gone above where the regular regen starts..so it is indicates multiple incomplete regens to get there. People who drive mostly highway, and longer commutes/trips will likely never see the keep driving message. Use the car for very short trips only, and that will set it up for all kinds off emissions problems. 

The trend here on all cars is to rely less and less on driver interaction with the car, less information, more automation. Those of us who like that information are a tiny market, GM won't mass produce a car for our wants, and it's looking like 2018 might be the last of the manual transmission Cruze, its already rare now, and in many models it is not even an option. 

Since I do monitor for regens, I find the best way to keep from issues is to let the regen finish, in most cases start to finish it is less than 20 minutes.. so it might mean I drive an extra 5-10 minutes on my commute, but it seems to work in preventing any problems.. I wish there was a built in way with the car to indicate normal regens, but there is not. That said, I can tell without a OBD 2 read, there are indicators. MPG will drop, the car will surge a bit when adjusting throttle in cruise control (all my DPF Diesels do this, Gen 1, Gen 2, and Cummins). That however requires paying very close attention to the car, something very few modern drivers do.


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## MRO1791 (Sep 2, 2016)

Oh, one other way to avoid the interrupted "pre-regen" problem, without a scan gauge: let the car idle a minute or two after you park, before shutting it off. In worst case where it started pre-regen, it will at least be out of that mode, and you should have cleared what is likely un-burned fuel, or some of it. This is also a good idea because once you shut off the car, the oil flow stops.. if you have very high EGTs prior to shut off, that heat will now accelerate the degradation of the oil left in the turbo since there is no more oil flow to remove the heat, and only then only losses to ambient. It's not required, but it can help prolong the life of the oil, and engine.


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## Aussie (Sep 16, 2012)

MRO1791 said:


> We don't get warning lights for a normal regen event.. this would be too much information for too many people here, thus we don't get it. The warning message to keep driving will only display in rather unusual cases where the soot levels have gone above where the regular regen starts.


That is how the region light works as well. I only saw it twice in 60K km of over 90% city driving. City driving here is much slower than what you have in the USA. Far to many 50kph roads and lights etc. Car almost never gets past 4th gear as it needs over 80kph before it will change up. Car has the 6T45 transmission and a 2.64 final drive ratio.


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## BDCCruze (Jul 12, 2017)

Was playing with a scan tool today and saw my car shows 785 miles average between regens. Not sure if that's about right or not but I was expecting it to regen daily.


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## Rivergoer (Mar 30, 2017)

BDCCruze said:


> Was playing with a scan tool today and saw my car shows 785 miles average between regens. Not sure if that's about right or not but I was expecting it to regen daily.


785 sounds accurate, I generally see regens (Scan Gauge 2) between 650 -750 miles. Have had a few over 800 miles, others here have reported up to 1,000 miles between regens.

Regen frequency depends on a number of conditions so there’s no ‘set’ time or distance. 

You won’t see daily regens, not unless you’re doing over 600 miles a day.


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## BDCCruze (Jul 12, 2017)

Reading somewhere where people claiming the DPF only last around 100k miles. Is there any truth to that? Otherplaces say that it should last the life of the vehicle if you do enough highway driving to let it regen.

Do we have any really high mileage drivers (150k +) that have had to replace it?


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## boraz (Aug 29, 2013)

BDCCruze said:


> Reading somewhere where people claiming the DPF only last around 100k miles. Is there any truth to that? Otherplaces say that it should last the life of the vehicle if you do enough highway driving to let it regen.
> 
> Do we have any really high mileage drivers (150k +) that have had to replace it?


manufacturer claims life of vehicle but it is a wear item

life of vehicle means what?

it should last 200k miles, most wont keep vehicle that long


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## grs1961 (Oct 23, 2012)

DPF lifetime is an interesting question, they've been in use in Europe for over a decade, and there hasn't been a spate of DPF replacements, it's not something I let myself worry about.

And the DPF on a DEF equipped vehicle gets a lot less of a work-out than a standalone DPF, (but it may be smaller).

I plan on keeping my Cruze until it falls apart, after eight years the only non-maintenance or recall item I have had is an engine mount replacement.


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## Aussie (Sep 16, 2012)

grs1961 said:


> DPF lifetime is an interesting question, they've been in use in Europe for over a decade, and there hasn't been a spate of DPF replacements, it's not something I let myself worry about.
> 
> And the DPF on a DEF equipped vehicle gets a lot less of a work-out than a standalone DPF, (but it may be smaller).
> 
> I plan on keeping my Cruze until it falls apart, after eight years the only non-maintenance or recall item I have had is an engine mount replacement.


My only issue has been poor metal in the front rotors, which I resolved myself as I don't see the point of replacing rubbish material with more rubbish material.


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## BDCCruze (Jul 12, 2017)

grs1961 said:


> DPF lifetime is an interesting question, they've been in use in Europe for over a decade, and there hasn't been a spate of DPF replacements, it's not something I let myself worry about.
> 
> And the DPF on a DEF equipped vehicle gets a lot less of a work-out than a standalone DPF, (but it may be smaller).
> 
> I plan on keeping my Cruze until it falls apart, after eight years the only non-maintenance or recall item I have had is an engine mount replacement.


Well I hope the DPF they use in the US is as good as the one used in Straya.


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## Aussie (Sep 16, 2012)

BDCCruze said:


> Well I hope the DPF they use in the US is as good as the one used in Straya.


My Australian Cruze has a different diesel engine to the one grs1961 has and my DPF has been faultless since I bought new in 2012. Most of my driving has been slow suburban and the occasional trip.


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## grs1961 (Oct 23, 2012)

BDCCruze said:


> Well I hope the DPF they use in the US is as good as the one used in Straya.


Well, mine's Korean, I don't know where the DPF was made, probably China, like 99.9999999% of everything these days.


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## pfw_dfw (Sep 13, 2018)

diesel said:


> First off, if you do not have a monitor like a Scangauge II, you will not be able to see this. Also, the odds that it will happen to you are VERY LOW, but it is possible. It happened to me the first time at 115K miles,
> 
> For those of you with a monitor - DO NOT shut your car off during this "Pre-Regen" period. It will cause a DPF Full message and send you to the dealer. My theory is that it's heating up the exhaust but it's not yet hot enough to start burning off the soot, and the extra fuel will be mistaken by the sensors as extra soot. I had my grams of soot go from 22-35 immediately once and this is why. 32 Grams is the threshold to force a manual regen which at this time can only be done by a dealership. Also, if you drive too far with the "DPF Full" and "Reduced Power" message, it is possible to ruin the DPF.
> 
> Here's a video. The "Pre-Regen" is before a regen is indicated by a 1 on the gauge, but when the MAP is below 14, or the boost is negative.


There is no reason whatsoever why there should not be a Manual Regen function programmed into the Center Display
Console:
Regen DPF?
When Pressed:
Confirm Regen DPF? Notice: You will not be able to Manually force a Manual Regen DPF for another 200 Miles.
Y/N?
Are you Sure?
Y/N?
Display: Manual Regen in Process.


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## Snipesy (Dec 7, 2015)

grs1961 said:


> DPF lifetime is an interesting question, they've been in use in Europe for over a decade, and there hasn't been a spate of DPF replacements, it's not something I let myself worry about.
> 
> And the DPF on a DEF equipped vehicle gets a lot less of a work-out than a standalone DPF, (but it may be smaller).
> 
> I plan on keeping my Cruze until it falls apart, after eight years the only non-maintenance or recall item I have had is an engine mount replacement.


I’ll be honest I have never seen them break before. Every single incident of a “DPF FAILURE” I have seen was in fact a misdiagnosis.

And this is including $1,000,000 construction equipment.

The worse stress they go through is if they are clogged and then the subsequent burning. But we are not gas engines so it just doesn’t get hot enough. The only time it does happen is if you drive tens of thousands of miles on a clogged DPF. That persistent heat up cool down will start causing damage... But again.... It takes a super long time of obvious neglect.


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