Chevrolet Blazer check engine light comes on

Filed Nov 4, 2026 · Engine, Transmission · GA

On [XXX], my 2021 Chevy Blazer broke down in the middle of traffic in a left turn lane when it tried to auto-restart. I was left stranded for 2 hours and had to call the local police to direct traffic around me. Upon towing to a local auto shop, and then another two to Carl Black GMC in Roswell, Georgia, I learned that the engine had completely seized due to a leaking radiator. They quoted me $14,000 in repairs between the radiator and a new engine. The vehicle had approximately 84,000 miles at the time and GM offered $3,000 to help with the engine. The car never threw a check engine light prior to the engine completely seizing. The coolant temperature gauge in the car also never showed temperatures above normal. At a few points, the car fan ran loud after turning the car off and I thought this might have been electrical. I sanded and cleaned the ground connection to the chassis which seemed to fix the issue. I also learned of Special Coverage N252508350-Engine Coolant Thermostat that was issued by GM which indicated this condition could be caused by a coolant engine thermostat that could open at a low temperature. I had planned to get it completed along with the fuel pump control module recall at my next opportunity. This issue with my car left my stranded in the middle of a busy highway with cars zooming around me. GM has known about the issue of leaking radiators in 2021 Chevrolet Blazers for years and has never done anything about it. Between their shoddy electrical systems and the radiator, these cars are of significant risk of seizing up in the middle of traffic with no warning like mine. GM has refused to replace these radiators or issue a recall becaus the repair is $2,000 and affects multiple lines of vehicles.

Filed Nov 2, 2026 · Engine, Steering · VA

Steering assist reduced message appeared Check engine light appeared, po128 code, thermostat and sensor defect. Common problem with these vehicles, GM has only recalled 2021 model even though the same engine and thermostat are on all V-6 models. Contacted GM, no assistance available on my year Blazer.

Filed Oct 28, 2026 · Engine, Steering · 51,000 miles · AR

The contact owns a 2022 Chevrolet Blazer. The contact stated that while operating the vehicle, the check engine warning light remained illuminated, and after turning off the vehicle, the fan continued running, causing the battery to drain. The vehicle was taken to the local dealer to be diagnosed, and it was determined that the thermostat needed to be replaced. The vehicle was not repaired. Additionally, the contact stated that recently while operating the vehicle, the steering assist warning light remained illuminated. The cause of the failure was not yet determined. The manufacturer was notified of the failure and informed the contact that the vehicle was not covered under an extended warranty coverage associated with the thermostat. The failure mileage was 51,000.

Filed Oct 22, 2026 · Engine, Steering · MI

2020 Chevy Blazer LT 3.6 L V6 I'm filing this complaint regarding multiple concerning mechanical and safety related issues with my 2020 Chevy Blazer LT that I purchased brand new and currently have 54,224 miles . Without warning, My vehicle developed several problems simultaneously. The check engine light came on, The engine cooling fan started running continuously at high speed, the AC stopped blowing cold air and is warm air, the steering assist reduced came on and my chevy app notified me that I have an engine cooling system malfunction and to service now. It's showing a P0128 code when I had it checked. After doing some research, I discovered GM issued a thermostat special coverage program for certain vehicles 2021-and newer models. Mine isn't part of it because of the year and isn't covered by the power train warranty for the same reason even though they all have the same engine. I only have 54,000 miles! I'm very concerned over the steering assist being reduced! What if the steering goes out while I'm driving? I have my grandchildren all the time. I need my car! There are several other complaints on here for the same vehicle and the same problem! Why isn't the 2020 Blazer covered under this special coverage program? The dealerships all say it's a well known problem! I believe this issue deserves investigation !

Filed Sep 17, 2026 · Brakes, Engine · WI

Vehicle Information: 2021 Chevrolet Blazer 2.5L engine, VIN [XXX]. Odometer 118000 miles.Description of Incident: While operating the vehicle, the mechanical brake vacuum pump experienced a catastrophic internal failure. The drive gear housing shattered violently without warning, shearing off the end of the connecting engine camshaft. Because this was an instantaneous mechanical failure, the vehicles computer did not trigger any dashboard warning lights, check engine lights, or safe mode protocols prior to the failure.Safety Hazards and Component Damage: First, the total destruction of the vacuum pump caused an immediate compromise to the brake booster vacuum lines, resulting in a sudden, dangerous loss of power braking assistance. Second, the sheared camshaft breached the engine valve cover or head, causing the engines pressurized oil system to instantly dump all engine oil externally onto the ground. Third, shrapnel or violent structural torque from the instant engine seizure punctured or severed the adjacent transmission cooler fluid lines and compromised brake fluid lines, causing total loss of transmission fluid and brake fluid simultaneously.Request for Action: This failure mirrors the exact mechanical defects documented in GM Technical Service Bulletin 21-NA-268 and previous GM vacuum pump recalls like the federal safety agency Recall 19V‑645, which excluded the 2021 Blazer. I am filing this report because the lack of an electronic warning indicator before a catastrophic mechanical brake and engine failure poses an extreme, immediate threat to highway safety. GM must expand recall coverage or issue a Special Coverage Adjustment for this model year. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 16, 2026 · Engine, Wheels · MI

My 2021 Chevrolet Blazer has experienced repeated problems involving the cooling system and is now exhibiting recurring symptoms that concern me about the vehicle’s reliability and safety. In 2023, the vehicle required a radiator/cooling-system repair. In 2024, it again required radiator/cooling-system repair, which was performed under warranty. The vehicle is now experiencing an abnormal humming/clicking noise from under the hood. The problem initially occurred primarily after rain but has become increasingly frequent. When the noise occurs, the air-conditioning system stops cooling properly and blows warm air. The check-engine light has also illuminated intermittently. The exact component currently malfunctioning is unknown. The vehicle remains available for inspection. Because the symptoms involve the engine compartment and follow multiple previous cooling-system repairs, I am concerned about the possibility of overheating, loss of proper cooling-system operation, an unexpected breakdown while driving, or another mechanical failure that could place the occupants or other motorists at risk. Authorized Chevrolet dealerships previously inspected and repaired the vehicle’s cooling system in 2023 and again in 2024. Despite those repairs, significant symptoms have returned. The current problem has not yet been definitively diagnosed, so I cannot state that the present failure is the same component previously repaired. The warning symptoms include the abnormal under-hood humming/clicking, loss of cold air from the air-conditioning system when the condition occurs, and an intermittent check-engine light. The symptoms have become more frequent over time. I am reporting this because of the recurring nature of the problem and the vehicle’s history of multiple cooling-system repairs. I request that the federal safety agency document and evaluate this complaint together with any similar complaints involving this model and model year.

Filed Sep 14, 2026 · Engine · 119,000 miles · OH

The contact owns a 2020 Chevrolet Blazer. The contact stated that while operating the vehicle, the check engine warning light intermittently illuminated, and the vehicle hesitated while accelerating. The vehicle was taken to the local dealer to be diagnosed, and the contact was informed that the catalytic converter needed to be replaced. The vehicle was not yet repaired. Additionally, while operating the vehicle, the engine temperature rose to HOT. The vehicle was taken to the local dealer, and the thermostat was replaced. The manufacturer was notified of the failure. The failure mileage was 119,000.

Filed Aug 21, 2026 · Engine · MI

While idling in my driveway, the engine started to shake and the check engine light came on. Got it diagnosed and was told by a private repair center that we had lost compression in cylinder 4 and that it was not worth the repair and we needed to replace the engine. Got it towed to the dealership, Bill Fox Chevrolet, for a 2nd opinion and they confirmed what the private shop had said. Because the vehicle was well maintained with regular preventative maintenance, it was deemed the failure was not the fault of the owner. GM extended a goodwill warranty to help cover the cost of the engine replacement (70% coverage. We were 1 month and 2,000 miles past our warranty). They never told us root cause, only that it would have cost more money to repair it than it would be to get a new engine. The Blazer had been running fine up to that point and was my wife's main mode of transportation. The Blazer only had 62,000 miles on it when the failure occured.

Filed Aug 18, 2026 · Engine, Transmission · NY

Thermostat went bad at 47,500 miles. Temp gauge stopped working, Engine light came on and alert stating steering assist is reduced

Filed Jul 21, 2026 · Transmission · 100,000 miles · MA

The contact owns a 2021 Chevrolet Blazer. The contact stated that while driving at an undisclosed speed, the accelerator pedal was depressed, and the transmission was slipping gears before the vehicle lost motive power. The contact stated that the vehicle failed to drive forward or move while in reverse. The check engine warning light was illuminated. The vehicle was towed to the residence. The contact, who was an independent mechanic, diagnosed the failure as a clutch solenoid failure. The contact stated that the transmission needed to be replaced. The vehicle was not repaired. The contact referenced an unknown recall; however, the VIN was not associated with a recall related to the failure. The dealer was made aware of the failure but provided no assistance. The manufacturer was made aware of the failure but provided no assistance. The failure mileage was approximately 100,000.