GMC Sierra Complaints (2021)

671 consumer complaints on file.

#11705363December 16, 2025
ENGINE
mechanical and electrical issues with my GMC Sierra Elevation Duramax Diesel, purchased in 2021. Despite multiple dealership visits, diagnostic evaluations, repairs, and software updates, these issues persist and have significantly impacted the reliability and safety of the vehicle. In December 2025, my vehicle was taken to the dealership for diagnostics and a third software update intended to resolve recurring engine-related faults. Throughout 2025, the check engine light illuminated on approximately 30 occasions, confirmed by at-home diagnostic scans. The same diagnostic code related to the 1) SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 2 P2C7A - Engine I 2) Exhaust Gas Recirculation (EGR) Cooler Efficiency Below Threshold P14D9 - Engine has appeared repeatedly since the vehicle was first purchased in 2021. Additionally, on approximately 15 occasions in 2025, the vehicle failed to start. When pressing the ignition button, the engine screeched while attempting to turn over for 20 to 45 seconds, after which the vehicle powered off entirely. After waiting approximately 10 minutes, the vehicle would then start normally. Notably, during these no-start events, no check engine light or diagnostic code appeared, and the engine light and starting failure have never occurred simultaneously. hese same concerns were explicitly explained to service technicians during the most recent recall repair in 2025. I was informed that a software update would resolve the issue. However, the problems have continued. A similar frequency of failures occurred throughout 2024. At that time, GMC advised that the issue was likely the vehicle’s battery. Acting on this recommendation, I had the battery replaced at my expense in October 2024 by the dealership. This repair did not resolve the issue. From the time of purchase in 2021 through January 2024, these same symptoms occurred approximately 10 times, demonstrating a long-standing and unresolved defect.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11704617December 11, 2025
ENGINE
Had a "Trans Hot Warning" light. Dealership said it was internal valve body failure. They said there is recall on this for other engine types even though this is same issue. I think GMC needs to expand their recall.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11704016December 9, 2025
ENGINE
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the engine seized. The contact was unaware of a warning light being illuminated. The contact stated that while attempting to start the vehicle, the vehicle failed to start. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The contact referenced an unknown engine recall; however, the VIN was not under recall. The manufacturer was made aware of the failure, and a case was filed. The contact was advised to report the failure to the NHTSA Hotline. In addition, the contact was informed that the VIN for the vehicle was a Canadian VIN, and the mileage was displayed in kilometers. The failure mileage was approximately 120,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11703710December 8, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2021 GMC Sierra 1500. The contact had received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The vehicle was taken to the dealer where an inspection was performed on the engine. The contact was informed that the vehicle had passed the inspection, and the mechanic added a higher viscosity oil, installed an oil fill cap, replaced the oil filter, and updated the Owner's Manual. The contact stated that the remedy failed to address or repair the possible defect with the engine. The contact stated that the remedy resulted in a higher cost for oil changes, and fuel economy had decreased from 21 miles per gallon to 18 miles per gallon. The manufacturer was made aware of the issue and the contact was provided a case number. The contact stated that the vehicle had not been repaired. The failure mileage was unknown.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11703711December 8, 2025
POWER TRAIN
Pulling into a driveway and the truck made a loud clunk and the check engine light, traction control light, and a reduced engine power light came on and the truck came to an abrupt stop. When the gear shift was put into reverse or any forward gear the truck would rev up without touching the gas pedal. The left rear wheel locked up. After paying over $700 in tow bills to get the truck towed to our house and then to the dealer we were told that the transmission had a catastrophic internal failure. This truck only has 82,000 miles on it and is a 2021!
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11703733December 8, 2025
LANE DEPARTURE: WARNING
Vehicle experiences a failure to the Lane Departure Warning and Intellibeam headlamps functions, primarily at night. Trouble first began on 3/12/2023 and has been to two GM dealerships for 11 repairs and the problem is still unresolved. GM Executive Escalations have been opened and the problem is still unresolved. Their response is that 18 vehicles experienced this problem and the resolution was to clean the front windshield and update the camera software. This truck has had the camera replaced and software updated three times by two different dealerships. GM is now stating they are unwilling to resolve the problem any further and they would no longer send any Field Engineers to investigate the problem. I have numerous photos, videos and repair logs from with the problem and resolutions performed. Nature of problem: At night, the indicator button for selecting the Lane Departure Warning will go out. If the button is depressed, a message in the DIC indicates Lane Departure Warning Unavailable and there is no way to activate the LDW. It also causes the Intellibeam headlamps to not work. Any help you can provide is greatly appreciated.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11703214December 5, 2025
ELECTRICAL SYSTEM
experience a automatic OTA update to the info system on my 2021 GMC Sierra(I did not iniciate) which burnt out the radio module which controls the info system. I am being charged $1,300+ for repair due to vehicle being out of warranty(52,000 miles) and no recall on this vehicle model for this issue. GMC does have a recall for this exact issue on the 2021 GMC Tahoe models, but not the GMC Sierra. If the GMC utilizes the same componets for both models of vehicle how doe the recall#N202319250 not cover the exact same issue on both models?
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11702889December 4, 2025
ENGINE
Heard a ticking noise then check engine light started blinking along with service esc and parking brake. Took it to the dealer and I had a bad lifter again. I was previously repair for lifters under warranty a little over 2 years ago.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11702830December 3, 2025
POWER TRAIN, ENGINE
On 10/21/2025 as I was traveling on the highway in Kansas at 60 mph, the vehicle lost power and the engine went into limp mode immediately reducing the speed dramatically. Multiple warning lights flashed on the screen. I was able to get the truck to the side of the highway. The vehicle never started again. I was informed by the dealer that the vehicle would need a new engine.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11701928November 28, 2025
ENGINE
The engine is knocking and running rough. I took it to Christian Brothers Automotive in Newnan Ga and the advised engine replacement.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11701448November 25, 2025
ENGINE, UNKNOWN OR OTHER
I purchased a 2021 GMC Sierra 1500 Denali (VIN: [XXX] ) from J.C. Lewis Ford in Pooler, Georgia. The dealership did not disclose an active federal safety recall (NHTSA Campaign Number: 24V-xxx / GM XXX) related to engine connecting rod and crankshaft defects that can result in sudden engine failure and loss of propulsion. The Blue Certified delivery document they had me sign includes a section requiring disclosure of any open recalls, but they left the recall section blank and checked that all recalls were explained to me. No disclosure of any recall occurred during the sale. The vehicle developed engine problems within days and is currently in GMC service. The nondisclosure put me at risk of driving a vehicle with a known safety defect. I am reporting this as a dealer nondisclosure of a federal safety recall. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11701251November 24, 2025
ENGINE
The contact's grandson owns a 2021 GMC Sierra 1500. The contact stated that after the vehicle was purchased from a private seller and driven 258 miles, while his grandson was merging off the exit ramp, the engine seized. The low oil pressure warning light was illuminated. The contact stated that the check engine warning light was illuminated prior to the failure. The vehicle was towed to the contact's residence. The contact scanned the vehicle and retrieved DTCs: P0011, P0016, P006DD, and P0521, stored DTCs: P06DD P0011, and permanent DTCs: P0011 and P0016. The engine was replaced by the contact. The local dealer was contacted for parts. No further information was available. The manufacturer was not contacted. The failure mileage was approximately 100,148.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11701315November 24, 2025
POWER TRAIN
During takeoff the transmission acted as if it was in neutral while I was crossing traffic luckily, the semi truck that was coming towards me was able to stop. I had the vehicle towed to a shop. After the vehicle was towed to the shop the transmission acted normal when the mechanic searched the VIN number. There was a service bulletin issued by General Motors for this exact problem. Had the semi not been able to stop. It could’ve very well killed me or my children. I suppose if it would’ve killed someone, maybe general motors would finally do a recall for this very disappointed in general motors and the NHTSA, the fact that this is an ongoing problem and has not been fixed and as a customer, I was not even notified that this problem existed is very alarming.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11700705November 20, 2025
ENGINE
I just surpassed my extended warranty (5 year/100,000 miles) by a couple of thousand miles and my coolant control valve has gone out. The problem is so common that the part is on back order for months at a time. GM says that they issued special coverage for 2020-2022 models, but my dealer is telling me that my VIN is not covered. They want to charge me $2,400 to replace it. This is insane. It’s a very common problem that they know about and it’s going to almost break me. We need help!
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11700059November 18, 2025
ENGINE, FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL
ENGINE BURNING OIL AND BLOWING WHITE SMOKE OUT TAIL PIPES. HAVE TO ADD OIL EVERY 1500 MILES OR SOONER IF TOWING. HAS BEEN AN ISSUE SINCE FIRST OIL CHANGE. VEHICLE IS NOW AT 88057 MILES
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11699845November 17, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2021 GMC Sierra 1500. The contact received the recall letter for NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The contact called the local dealer, who confirmed there was no information from the manufacturer to move forward. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The contact had not experienced a failure.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11699962November 17, 2025
ENGINE
While traveling to work at 75mph, a sudden an unexpected malfunction of internal engine components caused a loss of propulsion.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11699236November 13, 2025
ENGINE, UNKNOWN OR OTHER
I was traveling home from work and lost all power to the vehicle while driving. No warning lights, check engine lights came on. I was able to cross traffic and park it in a business place. I had it towed to a chevy dealership for diagnostic. They said that the timing chain came off and i would need a new engine. I had it towed to a auto mechanic shop for a second opinion and they gave the same result. The vehicle is only 4 years old with 92,000 miles on it. When i lost all power to the vehicle, I did not hear any strange noises.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11699295November 13, 2025
FUEL/PROPULSION SYSTEM, ENGINE, ELECTRICAL SYSTEM
I am an active U.S. Air Force member. My 2021 GMC Sierra 1500 failed GM Recall N252494003 on Sept 29, 2025 (L87 engine loss of propulsion). GM states this defect can cause sudden engine failure and loss of propulsion, increasing crash risk. Despite the confirmed failure, Ocean Cadillac (Miami, FL) told me to keep driving the unsafe vehicle and refused all Courtesy Transportation. The Service Manager admitted in writing that the engine failed, the defect can cause loss of propulsion, and the replacement engine is delayed under GM National Control for up to 3 months — yet they still denied me a loaner or rental. His statements contradict the GM documents he attached: • GM Bulletin DCS7222 says Courtesy Transportation CAN be provided during L87 recall downtime and dealers MUST consider loaners/rentals. • GM FAQ N252494002 says Courtesy Transportation IS available for this recall. • GM FAQ lists recall symptoms (check engine light, hesitation, high RPM, reduced power) — NOT battery drain. • GM states: “If the engine fails, the vehicle WILL lose propulsion.” Ocean Cadillac ignored these rules and put me back on the road in a known unsafe vehicle. As an American manufacturer, GM has a responsibility to protect American drivers. Their failure to follow recall procedures placed me, my family, and other motorists at risk. I request NHTSA investigate whether GM/Ocean Cadillac are complying with recall safety requirements and whether customers are being told to drive unsafe vehicles after confirmed failures.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11698609November 10, 2025
FUEL/PROPULSION SYSTEM, POWER TRAIN
I was driving on the freeway and my gmc Sierra at4 received a notification that I could could no longer accelerate. I pulled off to the side as safely as I could in a slanted hill in a major freeway with no shoulder. I sat on the side of the road for 45 min and then ran out of diesel gas waiting for the tow truck. We took into gmc and they said nothing was wrong, we were out of gas. But I ran out of gas waiting for the tow truck. The truck never shut off and ac still going, I just couldn’t accelerate. We’ve had the truck in the shop every single month for the past year for sensor issues and replacements and have all the documentation of the last few years of similar issues. No extensions of warranty’s nothing. Well we started to smell something burning this week and now we were told today we have a faulty fuel pump that will cost us $1,000 to fix and is not covered under our warranty. The truck is still under warranty, so why is something in relation to the power train not covered? There is a current t recall on other gmc models of this year for this fuel pump issue and the safety recall is EXACTLY what happened to us on the freeway and the issue we have now. Why has this not been extended to other GMCs????? My entire family could have died on the side of the freeway!!
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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