2021 GMC Sierra 1500 Driver assistance Problems

Push on accelerator truck barely would go, shifted hard, codes check engine lights flashing, engine sounded bad

NHTSA ID

11756397

Incident

May 29, 2026

When I put the vehicle in park, the dash warning says it is not in park or shift to park. The components continue to work. I have taken it to the dealership and according to the service manger, this is a very common occurrence in these trucks. This seems to me that it would be a very serious safety issue if one assumes their vehicle is in park and it is actually not. The shift to park warning is a safety warning to alert the driver it is not in park so the vehicle doesn’t roll off and hit someone (especially a child playing in the driveway). Assuming that alert is just a malfunction could get someone killed. I did notice that this was considered a safety recall for some models of GMC vehicles but not others. I’m not sure why there hasn’t been a recall on these trucks when the service manager specifically said they are having this issue on a lot of trucks.

NHTSA ID

11746746

Incident

Jun 1, 2026

The truck randomly will not detect that it was shifted into park. Shifting between gears and back to park does not automatically fix the the issue and has taken up to 10 mins to turn the truck off. The adaptive cruise controls stopped working and can still use regular cruise control. Just not adaptive. It appears greyed out. The truck has thrown the error code: P1098, Engine Coolant Control Valve Position Sensor Minimum Stop Performance. The truck would go into limp mode until the error was cleared. This error has appeared 4 times over the past five months. The most recent date of it happening was today. 06/30/2026

NHTSA ID

11741078

Incident

May 30, 2026

2021 GMC Sierra AT4, VIN [XXX] , NHTSA Campaign 25V-274, GM Case XXX. Brake pad monitor failed at 128,923 miles -- 24 miles after leaving Penske Chevrolet (released at 128,899, RO XXX, 04/17/2026). Brakes became spongy immediately following service. Monitor disabled entirely to stop recurring red Service System alert. Root cause is a burnt fuse block ground fault confirmed in writing by two GM-authorized dealers. Ray Skillman (RO XXX, 06/05/2025) documented the fault then deleted Labor Operation 14BUZ ENGINE ELECTRICAL from the recall repair work order. Penske documented verbatim: "all of these other faults share this same ground circuit." The recall repair at Ray Skillman used a remanufactured short block instead of a complete engine per N252494002. The original seized-engine oil pan has never been replaced across three dealerships and 128,000 miles. GM's own Part 573 filing states this defect "increases the risk of a crash." I drove 300 miles on an interstate on 04/22/2026 with active brake warning and no loaner because GM Executive Resolution refused to authorize one. Three GM dealers have inspected this vehicle. GM Executive Resolution Team [XXX] ) has not returned calls or emails and has not confirmed in writing this vehicle is safe to operate. OnStar issued a Critical Alert for P0617 on 04/15/2026. Zero brake faults existed in the 13 months prior to the Penske visit. This is a direct continuation of unresolved electrical damage from a botched federal safety recall repair at 384 days and counting. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11738685

Incident

Apr 22, 2026

I was driving on a highway on my way home from work. Thank god there was not a lot of traffic because my truck just shut off lost all power, then I received a message on the dash to put on neutral and restart. I tried multiple times to turn it back on. It never turned on and had to get it towed to nearest dealership. It took them a week to inform that the engine locked up even though I tried to take it for the recall they told me to wait and reschedule the appointment. Never got a new appointment until the engine failed and I got it towed to the dealership and have also not received a new kind of loaner from GM. This will be my last GMC truck I purchase.

NHTSA ID

11719556

Incident

Feb 9, 2026

The front camera stopped working, causing the safety systems to shut off. Codes U026A & U0078 "no communication failure". The camera was ordered and replaced.

NHTSA ID

11710140

Incident

Jan 21, 2022

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.

NHTSA ID

11703733

Incident

Mar 2, 2023

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

NHTSA ID

11700059

Incident

Nov 18, 2025

I just took my 2021 GMC Sierra 1503.0 Duramax diesel into Faulkner Nissan, today 10/18/2025 m, to have that recall fixed. I picked it up from the dealership and drove about 10 miles before it went into limp mode and reduced power mode while I was driving and started to shift very roughly and I’ve never had any issue like this before they supposedly fix this recall, I think the software patch made it worse in my case. Now my vehicle is throwing a bunch of different transmission error codes, that it has never produced , and it is going into reduced power mode,as I’m driving and going into limp mode as I’m driving, which you never has done before And it feels like it’s stuttering in early gears now and the idle was really rough it didn’t idle at a specific spot it went from 800 to 1300 back down to 800 when it should’ve just been idle at 800. I don’t know what to do. It seems like this recall made the problem worse for me and my truck in this case, I don’t know what to do and I don’t know where to go. I hope you guys can help us. Please make GMC take responsibility Before somebody gets killed. If they haven’t already this issue is extremely DANGEROUS AND I’M SURE IS DESTROYING THE TRANSMISSION. I don’t feel comfortable driving my family in my vehicle anymore because of this issue it is terrifying….

NHTSA ID

11694346

Incident

Oct 18, 2025

DTC CODE P1098 PRESENT RELATED TO FAULTY COOLANT CONTROL VALVE ON 3.0 DURAMAX DIESEL ENGIINE. THIS IS A KNOWN ISSUE WITH THIS ENGINE AND IS SUPPOSED TO BE COVERED UNDER THE 100K MILE POWERTRAIN WARRANTY. PREVIOUSLY TOOK VEHICLE INTO DEALERSHIP FOR REPAIR INVOLVING REPLACEMENT OF THE COOLANT CONTROL VALVE BUT WAS TOLD REPROGRAMMING OF THE ECM WAS REQUIRED FIRST STEP PER GM REPAIR BULLETIN. REPROGRAMMING COST ME $195 AND WAS TOLD THIS WAS NOT COVERED UNDER THE 100K POWERTRAIN WARRANTY. NOW, A FEW MONTHS LATER, THE SAME ISSUE AND DTC CODE P1098 HAPPENED AGAIN WHILE DRIVING ON FREEWAY AT FREEWAY SPEEDS AND CAUSED VEHICLE COMPUTER TO LIMIT SPEED OF THE VEHICLE WHICH CAUSED HAZARDOUS SITUATION IN CONSTRUCTION ZONE AS WAS NOT ABLE TO MAINTAIN SPEED OF TRAFFIC WHILE TOWING TRAILER WITH BOAT. I ALSO UNDERSTAND THAT GM HAS ISSUED SPECIAL EXTENDED WARRANTY RELATED TO THIS COOLANT CONTROL VALVE IN SEPTEMBER 2025 WHICH EXTENDS THE WARRANTY COVERAGE UP TO 15 YEARS AND/OR UP TO 150K MILES BUT I WAS TOLD AT THE DEALERSHIP THAT MY VIN# DOES NOT QUALIFY FOR THIS EXTENDED COVERAGE FOR SOME UNKNOWN REASON?

NHTSA ID

11693377

Incident

Oct 10, 2025

2021 GMC Sierra 1500 [XXX] miles 36,500. My childs seatbelt does not work and the lane keep assist does not work INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11678503

Incident

Aug 5, 2025

The engine coolant flow control valve position sensor is faulty. I brought mt truck in to my dealership and I have been waiting for over a month to get the issue fixed because “the part is on backorder”. This issue makes my truck sound like a jet engine because it makes the truck think overheating and causes the fan to come on at full blast. After drivinf for awhile it goes into “ reduced engine power mode” which is totally unsafe because it reduces the horse power to that of a lawn mower. It takes about 30 seconds to get from 0-60, so merging onto freeways or in conditions where you need extra speed its completely useless and increases the scenario of being rear ended, immensely.

NHTSA ID

11660285

Incident

Apr 25, 2025

El motor de mi camioneta falló por completo empezó a hacerle unos ruidos muy fuertes dentro del motor con solo 80,000 millas es del 2021 la compré el año pasado no llegó ni un año de uso una camioneta que supuestamente era muy buenas Estaba en el momento de lo sucedido estaba con mi mujer y mi hijo en el auto regresábamos de un restaurante acá en Miami y la camioneta se paró de pronto La camioneta fue inspeccionada por la garantía extendida la cual no asumió la reparación Luego del problema si salieron luces amarillas y rojas en la pantalla de mi camioneta

NHTSA ID

11659180

Incident

Feb 15, 2025

Tried to accelerate and heard a loud pop and the truck didn’t accelerate. Pretty much went idle in the middle of the road. The check engine light, the traction control light, and the ABS light all came on. I would press on the gas and it would rev but nothing would happen till a few seconds later the RPM’s would shoot up and you could tell it was trying to get going but didn’t very slowly and I would hear a clicking noise every time it was around the second gear. It put my children and myself in danger because traffic was heavy with vehicles going 70+mph merging into one lane. Took it to a dealership and they stated it was the the push rod and camshaft were damaged and all 16 lifters should be replaced and camshaft also. No, the vehicle has not been inspected by any of those except a car dealership and a mechanic. This problem first appeared the day it happened and continued after. Even took it to a mechanic and had all 16 lifters changed and problem still persists. Spent over $6,000 on a brand new truck and it is still undrivable because every time you get in to drive it the cylinder #2 misfires.

NHTSA ID

11657410

Incident

Oct 9, 2024

On the morning of 1/19/25, my 2021 GMC Sierra 6.2L AT4 went into limp mode heading south on HWY 207 in Leavenworth, WA at approximately 60 m.p.h. Fortunately, I was able to avoid a rear end collision. I quickly turned the truck off in the middle of the road and restarted it with a CEL. When I returned home almost 180 miles away, my local mechanic diagnosed a code P0303 and cleared it. Since, the truck has continued to shutter at various speeds without throwing a code. It is currently at Haselwood GMC in Bremerton, WA being scanned, recorded, and findings set to GM waiting for resolve. I have notes, exact dates, times, call records, return voice mail messages, and dealership personnel spoken to, etc. The dealer’s lead technician and I were able to replicate the shutter on a road test together on 1/27/25 at 3 p.m. after having driven just 10 miles. During my visit on the morning of 1/30/25, the lead technician stated he has since been able to replicate the shutter seemingly getting worse. I was strongly encouraged by the service manager, service writer, and lead technician their collective “personal recommendation” was to not take the truck back. Haselwood has had the truck since 1/27/25. Still awaiting a response and resolution.

NHTSA ID

11640251

Incident

Jan 19, 2025

I am writing to complain about that General Motors has issued a retrofit program for 2022 model vehicles that did not come with safety features due to the microchip shortage. I purchased my vehicle new in 2021 and the vehicle did not have the option of having safety features at the time of purchase. I find not having the safety features in a large vehicle to be a safety concern for those that use the vehicle or around the vehicle. General Motors should add the 2021 model vehicles that also did not have the ability to have those features on them added as a part of their retrofit program.

NHTSA ID

11591530

Incident

May 30, 2024

The contact owns a 2021 GMC Sierra 1500. The contact stated that he had received an unknown Manufacturer recall notification related to the Back Over Prevention camera. The vehicle was taken to the dealer and the recall repair was performed. Upon return of the vehicle, the grid pattern on the camera was very dim and was not visible to the contact while in use. The vehicle was taken back to the dealer where he was informed that the recall was performed correctly and that no further repair could be performed. The manufacturer was notified of the failure and a case was filed. The contact was then referred to Bob Clapper Automotive (3601 E Milwaukee St, Janesville, WI 535460) for further assistance. The vehicle was taken to the dealer; however, the dealer offered no further assistance. The dealer provided the same information as the original dealer. The vehicle was not repaired. The failure mileage was 7,000.

NHTSA ID

11481375

Incident

May 10, 2022

Mileage

7,000 mi

I took my truck to the dealership because of my issues and they said they had many trucks going in with the same issue but there was no fix to it. The issues Popping Noise Heard On Hard Turns and/or Going Over Speed Bumps, Creaking Noise While Turning Wheel Left and/or Right, Clicking Noise Heard On Slow Sharp Turns.Also when you go over a bump the truck makes a spring loud noise to the point that the whole truck bounces. shifter is also very hard when you try to change gears.

NHTSA ID

11479962

Incident

Jun 1, 2022

When using adaptive cruise the brakes have engaged aggressively without cause. This has happened several times prior to my discontinuing the use of this option. I have not had it in for service yet (we just returned from vacation).

NHTSA ID

11467248

Incident

May 30, 2022

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at undisclosed speeds, the Lane Departure Assist warning failed to activate when the vehicle drifted out of the driving lane. The failure was intermittent. The cause of the failure was not yet determined. The vehicle was taken to the local dealer who was unable to identify the cause of the failure. The contact was informed that the vehicle operated as intended. The manufacturer was notified of the failure. The failure mileage was 100.

NHTSA ID

11419885

Incident

Jan 20, 2021

Mileage

100 mi

BRAND NEW 2021 SIERRA AT4. KEEP LANE ASSIST HASN'T WORKED SINCE DAY ONE. LANE DEPARTURE WARNING EITHER. IT'S BEEN TO THE DEALER TWICE AND STILL NO SOLUTION. IT WON'T TURN ON

NHTSA ID

11388759

Incident

Dec 24, 2020