Vehicle Speed Control Problems of GMC Sierra 1500 - part 1

6 month old, 9,000 miles 2026 Sierra 1500 with duramax 3 liter suffered an engine control module failure 4 hours into a 12. 5 hour drive home from family vacation. First a transmission service warning flashed, then an emissions system failure with a forced speed reduction warning. This happened with two children and a dog in the vehicle. Onstar did diagnotics and said I had to see a dealer. Fortunately one was nearby and they determined the engine control module needed to be replaced--but I was 8. 5 hours' drive from home with kids and dog and would have had to stay for 2-4 days awaiting parts and repair. I traded the truck at the dealer for a new vehicle and drove that home. This was a major safety concern traveling with children and a dog on a nearly 100 degree day. And it was a brand new vehicle.

Current unsafe conditions: post-replacement active safety failures. The vehicle presently exhibits two distinct categories of active, ongoing, and dangerous safety failures, both of which were introduced as a direct result of the engine replacement performed by monument Chevrolet: (a) severe drivability failure. Between approximately 1,500 and 5,000 rpm, the engine repeatedly and without warning lunges forward, drops all power, and lunges again — cycling in this manner between three (3) and six (6) times before stabilizing. This behavior occurs across all gears and driving conditions, which creates a severe and unpredictable hazard particularly when merging into traffic or accelerating onto highways. This failure constitutes an immediate and ongoing risk to the safety of myself and other motorists. (b) complete adas system failure. The frontal crash response warning light is permanently illuminated on the instrument cluster, rendering the following federally relevant safety systems entirely non-functional: (I) automatic emergency braking / forward collision alert; (ii) cruise control; and (iii) lane change assist / lane control system. All of these systems were fully operational and properly functioning before the vehicle was submitted for the engine swap. Their failure is an assembly defect introduced by monument Chevrolet during the course of the repair and constitutes a warranty and safety defect for which general motors, as the manufacturer and warrantor, bears full responsibility. Medical hardship and urgency. This vehicle is my sole personal transportation. It is essential for travel to active medical appointments and upcoming medical procedures. The ongoing failure of general motors and its authorized service network to restore this vehicle to a safe and fully operable condition has created a serious hardship that directly affects my ability to access needed medical care. Yes, it was driven by a service department supervisor. He did experience the issues.

See all problems of the 2022 GMC Sierra 1500 🔎.

I was driving to work on 7/20/26 and my vehicle loss engine propulsion , engine failure and unable to restart vehicle and shift gears.

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

See all problems of the 2021 GMC Sierra 1500 🔎.

The truck side toy down shift and the accelerator was very high…. When I was going to park the reverse was not shifting….

See all problems of the 2023 GMC Sierra 1500 🔎.

I was driving my family on the highway and my truck completely shut down. The screen flashed a warning and it slowly started decelerating. Thankfully I was able to make it to the shoulder of the road safely. Engine failure was a known safety issue with my model of truck, but I completed the l87 engine loss of propulsion safety recall testing on 9/18/2025 and was assured my engine passed the testing and was not at risk for engine failure.

After driving my vehicle for a short period of time I stopped to go shopping. When I returned to my vehicle I started it as usual and the check engine light illuminated. I began driving and within 0. 25 miles I received an info enter message that stated my vehicle would have reduced acceleration and to please drive safely. My engine fans became noticeably louder and ran the entire trip home (about 15 minutes). After pulling into my driveway I sat in the vehicle and listen to the fans continue to operate. Additionally, my onstar system, wifi, and navigation systems quit working. A p1098 code was returned when using a diagnostic code device. Disconnecting the battery would cause the check engine light to extinguish and for the truck to operate without reduced acceleration; however, onstar, navigation and wifi would not work. After shutting off the engine and then restarting the check engine light would once again illuminate and the reduced acceleration message reappeared.

First occurrence was 02/27/2026 - onstar detecated a critical issue, the check esc, check tsc words came on in the center dash, then the orange lights came on and my truck went into limp mode at a stop light. I had to limp mode a mile to the nearest dealer. Where nothing was repaired just reset. Second occurrence - exhaust flap valve failed creating chirping noise resulting in a muffler replacement on 04/28/2026 - picked the vehicle up on 04/30/2026 third occurrence - 05/01/2026 came out after a wedding to start my truck which it immediately repeated the first occurrence, check esc, check tsc with the orange lights and chugging. Recorded on camera now the trucks been at the dealership awaiting updates.

See all problems of the 2025 GMC Sierra 1500 🔎.

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle decelerated to 30 mph. The check engine warning light was illuminated. The vehicle was taken to a local dealer, where it was diagnosed, and determined that the timing belt needed to be replaced. The part was on back order. The vehicle was not repaired. The contact stated the vehicle previously experienced brake failure, sensor failure, and glow plug failure. The manufacturer was contacted, but no assistance was provided. The bbb referred the contact to the NHTSA hotline to report the failure. The failure mileage was approximately 80,000.

See all problems of the 2020 GMC Sierra 1500 🔎.

Transmission blew on a 7 year old vehicle. Was replaced entirely and is now having the exact same problem again!.

See all problems of the 2019 GMC Sierra 1500 🔎.

At speeds of 65-75, both with the adaptive cruise control enabled and disabled, I accelerated a little bit to pick up speed and pass another vehicle. The vehicle responded initially by gaining speed, then it feels like I hit something and the front brakes lock up for 1-2 seconds and the tires start screeching from sliding, then everything resumes to normal. I was very shocked during a recent roadtrip when this happened 4-5 times. I feel like my safety and my family’s safety is at risk and of the 2 dealerships I called, they don’t prioritize it and make it seem like a minor repair.

See all problems of the 2024 GMC Sierra 1500 🔎.

My engine seized up on me on the highway. I was stranded and couldn’t start the vehicle and it was freezing outside.

The dfm program in the engine caused the lifters to fail and bend a pushrod which in turn scared the cam shaft. There were no signs leading up to this. It caused the traction control and brake systems to be compromised. I took vehicle into a gm dealer and had it diagnosed.

While driving I get a reduced acceleration warning on my dash cluster, drastically reducing horse power. My check engine light came on. This has happened before. I checked the code and it was a p1098 code. After researching I found out it was the engine coolant control valve. My fan is constantly running. This issue is ongoing. This seems to be a common occurrence with my vehicle year.

The front forward-facing camera module has failed, causing cruise control and driver-assistance features to become inoperative. Dealer diagnosis indicates the front camera must be replaced and recalibrated in order to restore cruise control and safety systems. This failure disables cruise control and driver-assist features that were standard equipment on the vehicle at purchase, resulting in a sudden loss of functionality while driving. The dealer has provided a repair estimate of approximately $1,150, including parts, labor, and required calibration, at owner expense. Based on similar reports from other owners, this appears to be a recurring issue affecting this model year.

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at 65 mph, the def tank failed. The vehicle went into three phases of limp mode and the vehicle unexpectedly decelerated while driving. The def system service message was displayed. The vehicle was taken to the local dealer, where it was diagnosed with def tank failure, and the tank needed to be replaced, even though the tank was full. The part was on backorder for several weeks. The contact was not provided with a loaner. The vehicle was repaired. The manufacturer was contacted and opened a case, but no additional assistance was provided. The failure mileage was approximately 70,000.

While traveling 60 mph on a divided highway went to pass another vehicle. Had no throttle response the engine had completely turned off, locked up seized up. I’m not sure what caused the engine to just lose all power. Had to go back to the lane and luckily there was a turnoff where I was able to turn off the highway.

Cruise control activates at speeds below 2 mph which frequently happens while turning or parking. The cruise control activates by a toggle on the left spoke of the steering wheel which can be easily bumped while doing low speed maneuvers like parking. When bumping the toggle the cruise indicator shows a set speed of 15mph and the vehicle surges forward trying to attain that speed. Since this occurs while maneuvering to park, it creates a dangerous situation if anyone is nearby and you are unable to react in time. This is an ongoing problem that can be duplicated at will.

I passed the recall inspection on 12/17/2025 and the higher viscosity oil was put into my vehicle. On 12/25/2025 my vehicle's engine shut off while I was traveling on the highway (I-25). The vehicle went into to neutral and I had to pull over to the side of the highway without power. The vehicle started again and as I was merging onto the highway it shut down again. The truck started again and I was able to drive it home. There were no codes found when I took it in for service on 12/26/2025. On 01/24/2026 I was driving on the highway (us-40) and I had complete engine failure. I had to get my vehicle towed to the service center and a new motor was installed. On March 27th the vehicle's engine shut off again while driving on the highway (us-191). There were no codes or check engine lights on this time either. The service records state that the starter mount stud was loose.

With no warning truck just started jumping in neutral after take off from red light litterly almost getting hit from behind and on coming traffic and than I let off the gas pedal than it jerks back in gear and doesn’t want to stop and wants to jerk to keep moving like transmission won’t stop pulling had to turn truck off it is something electrical in transmission I can pull fuse and it resets than it’s normal till it decides to do it again I’ve got on line and notice there is a lot more of the same truck and year having same issue and people have complained also mechanical at dealer says they have had many complaints on same issue I need my truck fixed it gave no warning and is to dangerous to drive like it is.

See all problems of the 2010 GMC Sierra 1500 🔎.

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….

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?.

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle shuddered while in first gear. The contact stated that the transmission sounded strained and shifted rough before slamming into gear. The vehicle was taken to the dealer; however, no cause for the failure was found. The dealer diagnosed the vehicle and determined that the vehicle was oversteering while turning to the right. The dealer replaced the valve and torque converter. On another occasion, while driving at an undisclosed speed, the vehicle accelerated independently. Most recently, a burned transmission fluid odor was coming from the front of the vehicle and entered the cabin through the a/c vents. There oil stains found on the ground on several occasions. The vehicle was taken back to the dealer and the valve body was replaced, the fluid levels were checked, and the transmission filter was replaced; however, the failure persisted. The contact called the dealer, and the dealer towed the vehicle. The dealer determined that the oil cap was loose. The vehicle remained at the dealer unrepaired. The manufacturer was made aware of the failure, and a case was opened. The failure mileage was 8,496.

The first time the truck stopped and wouldn’t want to start (engine light came up) after a few minutes and with a push the truck turned on. Next day while driving on freeway the truck shift hard pulling vehicle back as if it was going to stop without braking. Took truck to GMC dealer on 9/26/25 for an inspection with approx 17,000 miles. Oct. 17, 2025 GMC rep said my truck was inspected/ good to go and was ready for pick up. Not sure what part they had replaced. On oct. 18, 2025 picked up truck while leaving dealer I had my family in my truck about 3 miles into my drive we heard a loud clunk and the truck shifted hard slowing the truck down and display reduce acceleration drive with care and check engine light on. Have in mind we were on a busy traffic street driving while other cars had to pass us because we couldn’t speed up. I did not feel safe with my children in the car, left it again for the 2nd time with GMC service dept. Now we are almost reaching to a 30 day grace period without our vehicle.

This malfunction is ongoing and the dealership cannot fix the problem. The first time it happened in September 2025. I was driving down the road and the gauges started to go crazy. The screen on the dash said reduced acceleration. Then it said service esc. Then it said service traction control. It would not let me go over 40 mph. I took it to the dealership and they told me I needed a valve body replacement. They installed the valve body and that did not fix the problem. It happened again and said reduced acceleration took over forcing me to pull over on the side of the road. The GMC dealership said to bring it in again but they could not reproduce the malfunction after driving for a week. It happens randomly. The third time this happened I was traveling up interstate 24 at about 70 mph. There were semi trucks around me when the malfunction happened and my acceleration and speed was reduced throwing the rpms as high as they would go, and I was almost hit by a semi trying to move out of the way and onto the shoulder of the interstate I tried to accelerate to get out of the way of the semi truck but could not. I had to swerve over almost losing control of my truck. I informed the dealership that this had happened again and they asked me to bring it in. I did. They told me they were going to clean corrosion off of ground wires, and that should fix the problem. It did not. This keeps happening and I feel that the vehicle is not safe to drive. I do not know when it will happen again. I travel for a living and I feel the vehicle is unsafe to operate.

I am writing to express my extreme disappointment and serious concern regarding a critical safety failure I experienced with my 2025 GMC Sierra 1500 denali unlimited (VIN: [xxx] ), which I purchased brand new in April 2025 from cavender GMC, san antonio, TX. On Friday, [xxx], with fewer than 9,000 miles on the vehicle, I was driving on the highway at about 65 mph, with my minor son in the vehicle when the dash suddenly displayed a traction control (trc) fault message, followed immediately by "acceleration is limited. " the truck experienced a severe and unexpected power loss, severely restricting my ability to accelerate or maintain safe highway speeds. I was forced to pull off the road abruptly to avoid a potentially dangerous situation. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Driving on the highway under normal driving condition, my check engine light came on and said service transmission. This then put the truck into "limp mode" and I was stuck going 60mph in a 75mph zone. Dealership scanned and found that the coolant sensor control flow valve is faulty. This part is in such demand for these vehicles that it is unknown when the part will be in.

I am the original owner of a 2018 GMC Sierra 1500 with the 6. 2l l86 engine and 8-speed 8l90 transmission. I began experiencing severe transmission shuddering and harsh shifting, especially at lower speeds or under light acceleration. When the issue occurs, I press the gas and the engine revs up to 6,000 rpm without reaching 20 mph, making it extremely difficult — and dangerous — to merge into traffic or cross intersections. This issue has worsened over time and is now a critical safety concern, especially with children in the vehicle. I have researched this issue and found that many owners report the same transmission defect, and there is an open class action lawsuit and a gm technical service bulletin (TSB #18-na-355) describing the exact symptoms. The vehicle has become unsafe to drive. GMC should issue a recall or mandatory repair program for this known defect before someone is injured or killed.

See all problems of the 2018 GMC Sierra 1500 🔎.

I was driving with my wife about to merge into traffic on the interstate when I had a huge power loss. It was a busy part of the interstate where I could have been ran over. There was a lot of traffic and was fortunate the semi driver was alert and slowed down. I was not aware of any failures of this motor or received any notices from gm. After conducting research I found that this was a know issue that gm failed to report. My truck has been serviced regularly and until that point had not given any signs of a upcoming failure, I have read that gm is looking into other years such as 2019 which mine is. I have had no luck with gm customer care with the only response being I need to crunch the numbers from my claim advisor. I have the 6. 2 l87 motor and know of the clip failure do to poor assembly and parts and debris getting into the motor causing the failure. I am looking to report this and request any assistance available. My first stop was the dealership, then gm customer care.

During a turn in the parking lot my vehicle would not allow me to turn something with traction control came up on the screen. The past few days the car got stuck at 0 rpms while driving and did not feel I had adequate power and other times has stalled.

See all problems of the 2014 GMC Sierra 1500 🔎.

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.

Total loss of power while in motion on highway going 70 when first happened, got video of problem for shop while going lower speeds. Truck will loose all power the dash will turn off and then turn back on sometimes the engine will cut out completely.

See all problems of the 2017 GMC Sierra 1500 🔎.

The steering assist fails, power and steering is reduced at driving speeds. Steering wheel locks and vehicle looses voltage and stalls while driving at low speeds and have been close to collision. Vehicle was inspected by group one GMC in el paso texas. They did not fix recall because it "did not pertain to my VIN" . There is a recall for the steering assist on all GMC 2015 1500, but not for my GMC 2015 1500 for some reason. Whether it was manufactured in the us or the moon its still a GMC 2015 1500 with faulty steering assist system from the manufacturer with an open recall. Thanks for your help.

See all problems of the 2015 GMC Sierra 1500 🔎.

The vehicle was traveling over a hill, and it failed to shift gears downwards when traveling over the hill. The vehicle’s rpm’s shot up to 4000+ and jolted the truck forward without pressing the gas pedal. The vehicle made a loud noise and would not accelerate in the middle of the road. The vehicle would only accelerate after giving it minimal gas from the pedal. The truck then failed to accelerate on the entire drive to the destination and failed to enter reverse upon arriving to my destination.

I have experienced several occurrences of unintended acceleration while operating the vehicle at low speed. Two recent examples; 1) the truck accelerated rapidly while I was driving into my garage, and 2) the truck accelerated suddenly when pulling forward out of a parking spot in the morning shortly after starting the vehicle. In all cases, a hard application of the brake pedal slowed the vehicle. I considered whether this was operator error, possibly engaging cruise control inadvertently while turning the steering wheel, but the incident this morning does not support that potential cause. I have not spoken to the dealer about this issue.