2021 GMC Sierra 1500 Recalls, Ratings & Complaints

Incident: October 1, 2025 · Filed: October 29, 2026

I have repeatedly experienced a noticeable exhaust odor inside the cab while operating the vehicle\. The condition is particularly pronounced during cold weather when the vehicle is idling\. Under these circumstances, the exhaust smell inside the passenger compartment is distinct and concerning\. I have taken the vehicle to two separate General Motors dealerships in an effort to identify and resolve this issue\. On both occasions, I was advised that the vehicle was fine\. Despite these visits, the problem remains unresolved, and I continue to experience exhaust fumes inside the cab under the conditions described above\. My concern is that exhaust gases may be entering the passenger compartment, potentially exposing the driver and passengers to harmful emissions, including carbon monoxide\. Because carbon monoxide cannot be detected by smell, the presence of an exhaust odor does not establish whether carbon monoxide is present or at what concentration\. However, the recurring odor warrants a thorough investigation to determine its source and whether a potentially hazardous condition exists\. I am concerned that the issue may not be adequately identified during routine dealership inspections if the vehicle is not evaluated under the specific conditions in which the symptoms occur\. The fact that two dealerships have indicated that the vehicle is operating normally does not resolve my concern, particularly because the symptoms continue to occur\. I am requesting that the National Highway Traffic Safety Administration review this complaint and determine whether further investigation is warranted into the possibility of exhaust gases entering the passenger compartment of this vehicle\. I would appreciate consideration of whether this condition could represent a safety\-related defect that may affect other vehicles of the same make, model, or model year\. I have made reasonable efforts to address this matter through authorized GM service facilities.

Incident: June 11, 2026 · Filed: October 28, 2026

I am experiencing hard gear shifting in the low gears. It is very noticeable and I have a 10-speed transmission.

Incident: October 23, 2026 · Filed: October 28, 2026

2021 GMC 3.0 Diesel have coolant control valve issues. GM has a special coverage for them under Special Coverage N252508341. That coverage covers my year make and model. I have an open case with GM under GMC Customer Assistance opened case 116070735. GM is refusing to cover it due to this cited email. "After reviewing the vehicle information, we determined that Special Coverage N252508341 does not apply because it is not associated with the vehicle identification number (VIN) on your vehicle." I had the dealership and GMC customer service confirm this. GMC told me to request goodwill assistance at the dealership which the service provider had never heard of before. I can provide all documentation needed. I had recurring P1098, followed by a reduced engine power warning and unusually loud radiator fans. I figured it may be the coolant control valve and found Special Coverage N252508341. I created an open case with GM and took it to the dealership. The dealership was ambiguous about the issue and quoted me over 2,000 dollars just for further diagnostics citing "Coolant" and "Valve" in the documentation. They also said once they find the issue it would be "more." I took it to a 3rd party mechanic for an actual understanding of the issue. The mechanic found that the issue was the coolant control valve, which I have in documentation, and recommend a clear understanding of the repair and quote for the repair.

Incident: October 18, 2026 · Filed: October 21, 2026

Engine locked up while driving down the road at highway speeds. Lost all power and had to pull to shoulder of road. Was towed to dealership and confirmed engine locked up and covered under special recall. Was looked at a few months back and passed the recall test on engine. No lights or signs of engine failure before failure.

Incident: October 4, 2026 · Filed: October 20, 2026

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at 55 MPH, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The contact became aware of an abnormal sound, and the check engine warning light was illuminated. The vehicle was driven to the shoulder of the road. The contact inspected the vehicle and connected a portable diagnostic tester to the vehicle. The contact retrieved a pressure fault code. The vehicle was taken to the dealer, where it was diagnosed with a torque converter shudder. Additionally, the solenoids were clogged with debris. The contact was informed that the transmission needed to be replaced. The manufacturer was contacted, and a case was filed. The failure mileage was approximately 106,554.

Incident: September 12, 2026 · Filed: October 20, 2026

My 2021 GMC 1500 Sierra has the 6.2L motor that has significant known issues with catastrophic engine failure involving the camshaft and lifters. The engine in my truck has suffered the same failure but for some reason my VIN is not included in the recall of nearly 600,000 GMC trucks. I called GMC Customer Service and was told bluntly the recall was VIN specific and I would have to bear the 14,000 dollar repair. This is unacceptable since GMC is under federal investigation for knowingly and negligently manufacturing a flawed motor.

Incident: October 18, 2026 · Filed: October 19, 2026

My vehicle fits Special Coverage N252508341in every way, except the dealership tells me that my VIN is not covered. I drive a 2021 GMC Sierra 1500 with approximately 61,000 miles. This weekend a Check Engine Light illuminated with P1010 code. All the symptoms described in Special Coverage N252508341 were exhibited: the vehicle displayed 'Engine Power Reduced', and the electric cooling fans began operating at full output. I have taken the vehicle to Cronin GMC here in Perrysburg and it has been diagnosed with Coolant Control Valve failure that requires replacement. They state that my VIN is not covered by Special Coverage N252508341 and that I must pay full price for the replacement. I am writing to extend this coverage to my vehicle so I can either receive a no-charge repair or seek reimbursement after I pay for the service.

Incident: October 4, 2026 · Filed: October 18, 2026

The vehicle failed to start. It started after 30 minutes and I was able to drive it home. Then it starts and stalls after multiple attempts. Receiving codes P1177 and UI8A2. Was told that a bulletin exists for this issue on GM vehicles, GM Bulletin 24-NA-139, but I found out that it don't cover my VIN number. This can cause the vehicle to stall or shut off while driving. GM should make this bulletin for all vehicles of certain years who carry this modules.

Incident: October 16, 2026 · Filed: October 18, 2026

Service light came on because the brake petal would push back when I tried to start it. At times, I had to push down all the way almost to the floor and then it would start. If I eased up slightly or did not push all the way, the truck would hesitate to start. I brought it in to Courtesy GMC of [XXX]. They found metal debris in oil. The car warranty did not want to replace the entire engine as General Motors' bulletin had stated as a corrective solution. They only wanted to replace the camshaft and rocker arms because [XXX] did not tear down the engine to the point of failure. [XXX] stated that they did. After going back and forth with EasyCare (myself and [XXX]) I authorized the repairs EasyCare suggested. XXX, a Service Brake Assist message came on. I brought it to [XXX]. They rectified the issue. XXX,Truck stalled getting off XXX at light. Truck kept turning on and off. I put it in park and was able to turn in on. As I was driving the truck was rocking back and forth as I pressed the gas pedal. I was able to pull into the Super1 Foods parking lot. Trucked stalled halfway into parking lot. After two attempts to turn off and start truck I was able to pull it up all the way to ensure safety. Texted [XXX] at Courtesy. I called the number he sent and a tow truck from Cliff’s Towing and Recovery, LLC retrieved my truck and brought it to Courtesy GMC in [XXX] where it is currently residing. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Incident: October 8, 2026 · Filed: October 17, 2026

Loud engine knock, made it to dealer. Dealer confirmed engine failure as defined in the applicable recall. No idea when a replacement can be aquired. Unable to drive anywhere due to design and manufacturinf issues I did not cause.