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Check engine light on....and so it begins

15K views 41 replies 13 participants last post by  Timmy390 
#1 ·
P2201 (NOX sensor circuit range/performance bank 1) popped a few weeks back just before I found the oil pan leak. I cleared the code hoping it was just a freak deal.

Well it's back. Popped over the weekend. Trucks at the dealer now.

That's strike one for the emissions......

Sensor being replaced followed by a calibration then a forced regen.

Tim
 
#2 ·
Well truck is back home....

Customer states CK engine light is on, customer requests to no do any ECM updates.
NOX sensor position 1 poor performance resulting in P2201 ECM settings false DTC P207F due to software anomaly. Tested circuits to/from NOX sensor all OK. Replaced NOX sensor position 1 & setup. Preformed reduction quality test failed. Seeing P207F ran test again failed again failed setting P207F. (NOX sensors were reading 89PPM and 25PPM within spec.) Programed ECM with latest ECM updated calibrations per doc 2577094 claim code 11E62. Preformed reduction quality test again PASSED. No further DTCS and all DIC messages cleared System now working properly.

When I took it in the DIC was setting at 18.2MPG I got it back it's setting at 15.6MPG and it's in regen. I sure hope this don't kill my truck. I'm averaging 19.3MPG so far and my regens are between 650-700 miles. If that changes I'll be looking at "options" in the near future.

Tim
 
#3 ·
You'll be fine. The MPGs drop during a regen. Don't even look at that stupid thing; hand calculate your mileage. All that mileage readout does is to cause owners undue worry.
 
#5 ·
My DIC has historically been .5 MPG lower than hand cal. I track every tank.

Had the first real test of the truck this weekend. Filled up, zeroed out everything and headed to Atoka TN for a softball tournament. 430 mile round trip.

On the way over, DIC showed 19.8MPG average. I had to baby it to keep the MPG climbing. The trip back included to and from the hotel twice along with going to eat and to and from the ball park. I left Atoka with DIC at 19.1MPG and hit 19.6MPG by the time I got back home. That includes sitting 30 minutes in stop and go traffic on I-40 West.

On the way home there was no babying it but MPG kept climbing. Wonder if the ECM program update removed the "learned" driving habits and it had to learn over again?

Tim
 
#6 ·
Well the truck is back in the shop again. It's never been the same since the dealer "Programed ECM with latest ECM updated calibrations per doc 2577094 claim code 11E62". It's been using DEF at twice the rate it was (3K per 2.5 gal vs. 6K), regens quicker now (550-600 miles vs. the 650-700 I was getting) and I lost 3 miles to the gal on average. Since the trip to Atoka, I'm getting 16MPG average vs the 19.5 I was averaging.

Saturday the rig went into regen EARLY and wasn't acting right. I was about 2.5 hours from home when it started. I started home and noticed MGP was dropping like a rock. Much quicker than any regen I've had. Then pop goes the code P0420 (engine light on). Then MPG started going back up, then down, then up. My guess is it was trying to regen and failing. Got it home and it keep going in and out of "high idle".

Dealer has it now.......Looked at some 15's while I was there.....Blue Denali looked GOOD

Tim
 
#7 ·
That sux, 9th injector stuck closed? My 2012 was pretty much problem free other than a noisy oil pump... Traded it for a 2015 Denali and couldn't be happier, much more refined LML powertrain and the interior is heaven.
 
#9 ·
I had the DEF tank replaced last year and they did some reprogramming and ever since my regens have dropped to around 250 miles between regens.
 
#12 ·
Back from the dealer
NOX sensor #2 reading high Replaced
Poor Quality DEF
Indirect injector (#9) leaking diesel into exhaust Replaced
P207F, P20EE, P0420 causing regen to fail
Quality test on DEF passed
Dealer forced regen (soot level at 4G)
Performed reductive quality test to clear all codes and messages
All under Warranty
So it's back.....time will tell

Tim
 
#13 ·
First regen after the above trip to the dealer. 412 miles since the dealer forced a regen. Not good considering I was regening at about 550-600 with all the above wrong which was down from the 650-700 miles between regens before my issues started.

Not sure how my truck went form being GREAT to this.....

Tim
 
#16 ·
When does the Warranty go out? Time to delete sounds near and save all that headache of worrying with the def crap!
 
#24 ·
The 3 year 36K is up already but I have an extended 5 year 100K (only did this because it was a diesel) and that's up next year. Talked to a shop about deleting. Just want a stock tune nothing special.

Haven't got it into the dealer yet. I NEED MY TRUCK which is why I bought a truck. Going to try and get it n next week or week after to get the downpipe checked.

Tim
 
#18 ·
Timmy390,
My mileage has been terrible since the emissions system has been messed with. I have the same year and same motor as you in the Chevy brand. For various reasons this LML has been in the shop 24 times and has just 42k miles on it. I'm a very unhappy camper. The only way I would have stayed in the GM brand would have been a direct swap out with new. We went and looked at the Super Duty over the labor day weekend but they were not dealing as I would have hoped else I'd be driving one. We'll wait until the year end and see.
 
#19 ·
Tim,
That down pipe is most certainly the cause. I had that same issue. I understand that there is a new down pipe with a larger flange that makes seating the O-rings easier on the mechanic. When mine started leaking after the injector was replaced in it I placed a monoxide detector in the cab and sure enough it went off a few times. Especially when the air was on and outside air was blowing in. I hope they fixed this issue for you but it took several trips to the dealer and GM sent an engineer out to help them. During regen was the worst. smoke would actually come out from under the hood. My truck was barely a year old when this happened. The fuel milage was never the same after.
 
#20 ·
SuperblackTruck,
I had to take a video of that same experience and show it to the dealer. A cop had actually pulled me over thinking my truck might be on fire. Sigh!
 
#22 ·
48548,
That down pipe is a real problem for the LML motor. I agree it's a quality control issue from GM.
 
#23 ·
I had the window down and pulled up next to a hot chick and I was checking her out and next thing you know smoke is coming out from everywhere. I guess that ruined my chances of getting some. The dealer put it in regen and got it to smoke and replaced the pipe I think.
 
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#25 ·
Tim,
You shouldn't have to "delete" anything to get your truck to run correctly. I too will not just skirt US emissions laws to get what I should already have ~ a properly running truck I can rely on.

Warranty is a value add proposition that is intended to lure customers. Having the option of a warranty versus reliability I am certain would not be what GM would have it's dealers explaining before the contract is signed.
 
#26 ·
I think you need to just go get a dodge or ford and be happy since your lml has "failed" you so many times instead of bash and complain on a gm forum about your truck not running right. Its not gonna get you far on here, just letting you know.
 
#33 · (Edited)
Tim,
I mean what you said. Taking the emissions out will likely fix your fuel mileage issue. My point is that you shouldn't have to do that to fix your problem. GM should simply restore the truck to it's original working status. If they need to send out an engineer then so be it.

Have you had a factory engineer come out and look at it? That's one option. You can do this. That's how I got my down pipe fixed. You have to open a case at GM and make the request. You'll have a territory representative contact you. He'll suggest to bring the truck back in. They'll make another attempt, likely fail, and then you can get them to send out the engineer. They MUST abide by the original warranty and fix it and if they cannot you have better leverage.

I asked the guy out here, he's based in Phoenix, if I removed the EPA emissions equipment what would the consequences be he told me point blank that it violates the warranty terms and conditions and it was not legal. I know that's the default answer and so does everyone here.

But you mention 3 major issues going on with your truck right now. I have experienced each of them and still have had issues in other areas. But I would much rather that GM violate the T's & C's of the warranty than I do it.

You shouldn't have to either.
 
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