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Related GMC Questions
The DEF warning message won't go off on my Diesel 6.7L GMC
The DEF warning message won't go off on my Diesel 6.7L GMC 3500 truck. It's full of the correct DEF fluid, but warning message is threatening to reduce speeds. … read more
Jared D
Jared D
ASE Certified Technician
Bachelor's
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DEF is at 24% and hasnt reset for over 5000 miles. It is
DEF is at 24% and hasnt reset for over 5000 miles. It is full … read more
J Hall
J Hall
retired
none
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2012 GMC with duramax. Sierra denali. Check emissions system
Check emissions system warning on 60 miles till 65 mi/hr max. I'm in the middle of a trip I have 700 miles to go … read more
Andrew
Andrew
Master Diagnostic Technician
Associate of Occupational in Automotive Technology
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I have a 2011 GM Sierra 3500hd with the duramax lml engine.
I have a 2011 GM Sierra 3500hd with the duramax lml engine. I have a service exhaust message and another that says on next fill up I will be limited to 4 MPH. I think the problem is the reductant heat… read more
Gm Tech (Cam)
Gm Tech (Cam)
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Vocational, Technical or Trade Scho
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2017 GMC Denali duramax doesn't show how much deff left but
2017 GMC Denali duramax doesn't show how much deff left but still tells you it's ok but not the level of fluid … read more
BRIAN
BRIAN
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2019 GMC Sierra Denali HD. If I had codes deleted, can
If I had codes deleted, can dealership mechanic identify that … read more
Anthony P.
Anthony P.
ASE Certified, Ford Master, Honda Master
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2011 2500 Denali --poor quality exhaust fluid message along
2011 2500 Denali --poor quality exhaust fluid message along with the corresponding light on the dash. Got on the highway at 120 kmh and message gone, light cleared but engine light came on. … read more
Ethan Lankford
Ethan Lankford
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2012 gmc denali 2500 duramax. the "service exhaust fluid
2012 gmc denali 2500 duramax. the "service exhaust fluid system" indicator came on. went to max xpeed 65, then to max speed 55, now in 65 miles it will go to 4mph. Had a bad battery and changed it. Ha… read more
Tim Mohr
Tim Mohr
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Def light won't reset after adding fluid and speed has been
def light won't reset after adding fluid and speed has been reduced to 65 … read more
Chad Farhat
Chad Farhat
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Service Emissions System 2012 GMC Sierra HD Service Emission
Service Emissions System 2012 GMC Sierra HD Service Emission Systems on DIC P21AB Code on Torque app through Bluetooth OBDII Reader. … read more
Gm Tech (Cam)
Gm Tech (Cam)
GMC Mechanic
Vocational, Technical or Trade Scho
1,912 satisfied customers
2012 Silverado 3500 HD, Duramax, w/ 52,000 mi. (Just
2012 Silverado 3500 HD, Duramax, w/ 52,000 mi. (Just purchased) Check Engine Lamp on, Plus message "Exhaust Fluid Poor Quality" . Truck is in 65 mph limit, soon to drop to 55 mph. Added 2.5 gal. fresh… read more
Chris Carr
Chris Carr
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2012 GMC Denali HD Duramax Diesel. Engine idle has an
2012 GMC Denali HD Duramax Diesel. Engine idle has an occasionally mild surge when fully warmed up, in drive or reverse. How do I cure this?… read more
Gm Tech (Cam)
Gm Tech (Cam)
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Vocational, Technical or Trade Scho
1,912 satisfied customers
My husband's def system is saying that it is low. But the
My husband's def system is saying that it is low. But the resivior is full … read more
Roy
Roy
shop foreman
Associate Degree
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Second opinion] 2012 GMC HD Duramax. Intake pressure is
Second opinion] 2012 GMC HD Duramax. Intake pressure is reading 25.1 IN/HG with the engine off. Is this normal?… read more
Gary
Gary
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2011 GMC Sierra 3500 HD w/6.6 L turbo diesel with 36,000
2011 GMC Sierra 3500 HD w/6.6 L turbo diesel with 36,000 miles. "Exhaust Fluid Poor Quality" warning just recently came on the DIC along with the engine light on the dash. Put 2.5 gal. of Blue DEF int… read more
Master Auto Tech.
Master Auto Tech.
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Filled def tank and still won't go over 55 How do you reset
Filled def tank and still won't go over 55 How do you reset it? … read more
Pete
Pete
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General auto certifications
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I spend a lot of time on the road. i am retired. i usedto
I spend a lot of time on the road. i am retired. i usedto design and build 12V and 24V control systems. This winter my DEF started giving me strange readings. the tank was at 14% and it took maybe 1 g… read more
Roy
Roy
shop foreman
Associate Degree
5,217 satisfied customers
GM Sierra 2500 HD Denali: there. I just refilled my DEF
Hi there. I just refilled my DEF fluid and the display did not update. It still thinks I'm at 13%. I noticed on our last trip that the countdown to empty was erratic and jumped from 1000 miles to 181 … read more
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Meet the Experts:

Gm Tech (Cam)

Gm Tech (Cam)

GMC Mechanic

1,912 satisfied customers

GM Grand Master Technician 2007. 14 year experience.

Gary

Gary

ASE Certified Technician

1,589 satisfied customers

GCM master tech over 25 years

Dave Nova

Dave Nova

GMC Technician

929 satisfied customers

ASE Master Certification. GM World Class Certification

Chris (aka-Moose)

Chris (aka-Moose)

GMC Technician

766 satisfied customers

16 years of experience

JFN1

JFN1

ASE Certified Technician

272 satisfied customers

GM Master Technician

Don - Mo Lurch

Don - Mo Lurch

ASE Certified Technician

248 satisfied customers

GM, GMC, Chevrolet Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics

Mike S.

Mike S.

ASE Certified Technician

241 satisfied customers

GMC N.A.I.S.E. Certified Auto-Mechanic

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Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

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