I have a 20' Chevy LM2 with about 20k miles. Anyone having the same issue? The code I'm getting is P2C7A. First they said a software update would fix it, then it was a bad DEF sensor, and now it's back for a third time. It's under warranty, but I'm losing my time just waiting for them to guess what the problem is.
OffDisturbance
I saw the bulletin. That was the only thing I was able to find relating to the DTC I was getting. They had already reprogrammed the ECM during my first visit, and they replaced a sensor my second visit.
Was your programming update prior to Oct '21?
There was a programming update in October '21.
We know it dealt with the crank/no-start thing.
It may (likely) also has other updates / changes that we don't know about -- so possibly something that would impact your trucks issues.
Out of curiosity,
What type of def are you running?
Any fuel additives?
There was a programming update in October '21.
We know it dealt with the crank/no-start thing.
It may (likely) also has other updates / changes that we don't know about -- so possibly something that would impact your trucks issues.
Out of curiosity,
What type of def are you running?
Any fuel additives?
It was done after October. I've never had a no crank issue. I haven't done anything different. No special additives. I use NAPA DEF. I go to the same gas station that is have been throughout the year.
They said it was another bad sensor. They just received the sensor yesterday. I'll get it replaced tomorrow. During the week I waited the CEL went out on it's own.
I'll let you know after I get my truck back. The parts are on backorder. Who knows how long they'll be ):
I haven't posted in a while, simply because they still haven't received the part. I haven't had my truck for nearly a month now... They haven't given me any update for when GM will be supplying these parts.
I opened up a complaint with BBB Auto. Theres no cost for having them work on my case. They contacted general motors and expedited the part I was waiting for. They got the part within a week of the claim. Now we'll just have to see if the code comes back, typically I was seeing it once a week after it got cleared
So it's been a few weeks or rather more than a month and I have not had the CEL come back on. I guess it was a bad cat. I feel like it's going to go bad again sometime in the future or something else will fail because of it. I have a warranty forever on the truck, and GM contacted me to give me extended warranty for I think 2 more years/80k miles. So I guess as look as it's not coming out of my pocket I'll keep the truck.
They're probably going to change out sensors and make you have to come back a few times like they did to me. depends on the dealer ig I had such a bad experience Im going to a different dealer from now on
Brand new 2022 Sierra 1500 has been in 3 times and is headed back for a 4th. Truck spends more time at dealer than my house.
First time it was reset computer / clear codes - oh they're history codes they said so no issues reproduced. CEL back on within a day.
Back the next week - same codes - this time it took 10 days - replace cat - CEL on the way home
Back in the next week - replace NOX sensor - home last Friday - today CEL code P2C7A
Headed back tomorrow.... unreal.
First time it was reset computer / clear codes - oh they're history codes they said so no issues reproduced. CEL back on within a day.
Back the next week - same codes - this time it took 10 days - replace cat - CEL on the way home
Back in the next week - replace NOX sensor - home last Friday - today CEL code P2C7A
Headed back tomorrow.... unreal.
I'm not using biodiesel though. They also tested the fuel a couple times ago (API 41) to be sure. Not the issue.#PIP5856: Use of R-99 or R-95 Diesel Fuel - (May 26, 2022)
Subject: Use of R99 or R95 diesel fuel ![Image]()
Correction
B20 fuel is a blend of up to 20-percent bio components and 80-percent conventional diesel, which helps lower carbon dioxide emissions and lessens dependence on petroleum.
All Fuel must meet ASTM D975 diesel fuel standards. Renewable or BioMass fuels have an API of up to 50.
The API can be between 40 and 50, depending on if the fuel is a combination of #1, #2, and the R-99/95 fuel. This fuel is also clear in color when not mixed with other fuels.
Currently, we have four things to examine when testing fuel:
1) Look at the color of the fuel compared to what you normally see in your region. Cloudy looking fuel is an indication that there may be an issue with the fuel.
2) Look for any separation of the fuel. This can be anything from sediment settling or different layers like water being seen.
3) The third test is mentioned above and is the Specific Gravity (API) of the fuel.
4) Lastly, if you take a sample of the fuel, put it in a Styrofoam cup, and place the cup in a drain pan, fuel contaminated with gasoline will certainly melt the cup within half an hour. B20 Biodiesel will also melt in a Styrofoam cup, but will take about an hour.
Got the truck back again today by coincidence, and this time they replaced NOX sensor #3 so we'll see if that does anything.
Hello fellas, tech Tony here from a local Chevy dealer. This code is going to come back on every time yall use over 20% of fuel tank capacity with bio-diesel (its in the owners manual) ----Doc 4853915
Caution: Do not use home-made biodiesel or home test kits because the quality cannot be verified by approved scientific methods. Do not use raw vegetable oil or other unmodified bio-oils, fats, or blends of vegetable oil with diesel. They could damage the fuel system and engine, and damages would not be covered by the vehicle warranty.
Biodiesel Blends
Fuels with a biodiesel content up to 20% by volume may be used (e.g., named B20). Only use biodiesel blends up to 20% by volume that comply with your country’s or region’s fuel standards.
Caution: Do not use blends containing more than 20% biodiesel. Any engine, fuel system, or exhaust after-treatment system damage would not be covered by the vehicle warranty.
As a renewable fuel, biodiesel provides some environmental benefits. However, biodiesel has unique properties and needs to be handled differently than diesel fuel. Its use presents additional risks and may not be appropriate in all situations. Certain vehicle operating modes increase these risks and should be avoided.
Biodiesel fuel quality degrades with time and exposure to high temperature quicker than Ultra Low Sulfur Diesel fuel. More frequent refueling provides the best opportunity to have a supply of fresh fuel. Storage at hot ambient temperatures will accelerate biodiesel degradation.
If the vehicle is not driven often and uses little fuel, or if it is stored for extended periods of time, avoid the use of biodiesel blended fuels above 5% by volume. When the vehicle is stored for longer than one month, it should be run out of biodiesel to below one-quarter tank, refueled with biodiesel-free fuel, and driven several kilometers (miles) before storage.
Caution: Do not use home-made biodiesel or home test kits because the quality cannot be verified by approved scientific methods. Do not use raw vegetable oil or other unmodified bio-oils, fats, or blends of vegetable oil with diesel. They could damage the fuel system and engine, and damages would not be covered by the vehicle warranty.
Biodiesel Blends
Fuels with a biodiesel content up to 20% by volume may be used (e.g., named B20). Only use biodiesel blends up to 20% by volume that comply with your country’s or region’s fuel standards.
Caution: Do not use blends containing more than 20% biodiesel. Any engine, fuel system, or exhaust after-treatment system damage would not be covered by the vehicle warranty.
As a renewable fuel, biodiesel provides some environmental benefits. However, biodiesel has unique properties and needs to be handled differently than diesel fuel. Its use presents additional risks and may not be appropriate in all situations. Certain vehicle operating modes increase these risks and should be avoided.
Biodiesel fuel quality degrades with time and exposure to high temperature quicker than Ultra Low Sulfur Diesel fuel. More frequent refueling provides the best opportunity to have a supply of fresh fuel. Storage at hot ambient temperatures will accelerate biodiesel degradation.
If the vehicle is not driven often and uses little fuel, or if it is stored for extended periods of time, avoid the use of biodiesel blended fuels above 5% by volume. When the vehicle is stored for longer than one month, it should be run out of biodiesel to below one-quarter tank, refueled with biodiesel-free fuel, and driven several kilometers (miles) before storage.
#PIP5856: Use of R-99 or R-95 Diesel Fuel - (May 26, 2022)
Correction
B20 fuel is a blend of up to 20-percent bio components and 80-percent conventional diesel, which helps lower carbon dioxide emissions and lessens dependence on petroleum.
All Fuel must meet ASTM D975 diesel fuel standards. Renewable or BioMass fuels have an API of up to 50.
The API can be between 40 and 50, depending on if the fuel is a combination of #1, #2, and the R-99/95 fuel. This fuel is also clear in color when not mixed with other fuels.
Currently, we have four things to examine when testing fuel:
1) Look at the color of the fuel compared to what you normally see in your region. Cloudy looking fuel is an indication that there may be an issue with the fuel.
2) Look for any separation of the fuel. This can be anything from sediment settling or different layers like water being seen.
3) The third test is mentioned above and is the Specific Gravity (API) of the fuel.
4) Lastly, if you take a sample of the fuel, put it in a Styrofoam cup, and place the cup in a drain pan, fuel contaminated with gasoline will certainly melt the cup within half an hour. B20 Biodiesel will also melt in a Styrofoam cup, but will take about an hour.
| Subject: | Use of R99 or R95 diesel fuel |
|
Brand: | Model: | Model Year: | VIN: | Engine: | Transmission: | |
|---|---|---|---|---|---|---|
from | to | from | to | |||
All | All | 2006-2022 | All | All | All Diesel Engines | All |
Involved Region or Country | North America |
Condition | The use of renewable Diesel, R-99 or R-95 has been approved by GM Engineering for all GM vehicles with Diesel Engines. |
Cause | Renewable diesel (RD) is essentially any diesel fuel produced from a renewable feedstock that is predominantly hydrocarbon (not oxygenates) and meets the requirements for use in a diesel engine. |
B20 fuel is a blend of up to 20-percent bio components and 80-percent conventional diesel, which helps lower carbon dioxide emissions and lessens dependence on petroleum.
All Fuel must meet ASTM D975 diesel fuel standards. Renewable or BioMass fuels have an API of up to 50.
The API can be between 40 and 50, depending on if the fuel is a combination of #1, #2, and the R-99/95 fuel. This fuel is also clear in color when not mixed with other fuels.
Currently, we have four things to examine when testing fuel:
1) Look at the color of the fuel compared to what you normally see in your region. Cloudy looking fuel is an indication that there may be an issue with the fuel.
2) Look for any separation of the fuel. This can be anything from sediment settling or different layers like water being seen.
3) The third test is mentioned above and is the Specific Gravity (API) of the fuel.
4) Lastly, if you take a sample of the fuel, put it in a Styrofoam cup, and place the cup in a drain pan, fuel contaminated with gasoline will certainly melt the cup within half an hour. B20 Biodiesel will also melt in a Styrofoam cup, but will take about an hour.
Yeah it's not great. In a normal market we'd have already done this and be in a different truck but since supply is so low we gave them more attempts to repair.
Punchline is the truck drives well and I really still want one, so now it's go through the buyback process then wait months for another one.
Punchline is the truck drives well and I really still want one, so now it's go through the buyback process then wait months for another one.
At least you have lemon law/buyback in the US, I don't believe we even have that option up here in Canada (unless someone on here knows otherwise). I hear what you are saying though, the LM2 are nice, comfortable, quiet tucks that get good mileage and are capable for most who only want/need a 1/2 ton. I really do like mine and knock on wood have not had any issues thus far (though I did have to reset two P26BB codes in the first 675 kms, but they have not come back in 4000 Kms). Hopefully it keeps up...
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