Power Train Problems of Chevrolet Blazer - part 1

The transmission (powertrain) developed a delay when shifting into reverse, followed by harsh engagement. The condition worsened over time and resulted in a complete loss of reverse. The vehicle will not move when shifted into reverse. This creates a safety risk when parking, backing out of spaces, or maneuvering in traffic, as the driver cannot safely control vehicle movement. The issue occurred at approximately 89,000 miles under normal driving conditions. No warning lights were present prior to failure. The problem was reported to a dealership and diagnosed as a transmission failure. The condition is reproducible and ongoing. I was also informed that multiple vehicles of the same model were experiencing similar transmission issues at the same time. The failure limits safe operation of the vehicle and increases risk in situations where reverse movement is required.

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My engine coolant temperature sensor failed. Replaced it and still not fixing the issue. This takes my steering assist away as they are all interlinked? I have seen on forms this is a common issue. This has the potential to blow up my engine, I’m not sure how this is not a recall with so many 2020-2026 Blazer owners having the same issue.

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Once I turn the vehicle off, there is a loud sound coming from the engine area that sounds like a fan. Then the first incident of the fan ongoing after the vehicle was powered off, a battery light was on the internal driver dashboard and stayed on. The battery was recently replaced during 2026 so the battery should not be anywhere near dead, dying, or needing to be checked.

Just took my car to the chevy dealership today and had them go over the car because I keep getting the message steering assist has been reduced and the fan is constantly running at the highest speed and it also makes it where I can not use the a/c or heat in the car! I don’t know the code off hand but it has something to do with the cam shaft and the thermostat for the antifreeze! from what chevy told me today it is a $9000 job to tear down the left side of the engine because the camshaft carrier gasket is leaking oil! which is probably why that code is popping up. Or from what I was told today it could be from the battery which I believe they were trying to shift blame. Either way this camshaft stuff really needs to be investigated!!.

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I was driving to work as I normally do and work is only 15 miles away from home I get to work turn into the parking lot stop to scan my badge and I hear knocking noise I thought it was coming from the truck in front of me but after he moved on I still heard the noise and I found a parking spot as soon as I could and the engine light on the dash came on and the motor that was knocking is definitely my Blazer with only 11,222 miles on it. I always keep up on my vehicles maintenance in fact I just had the oil changed at ray skillman gm dealership2/16/26 it had 10,960 miles on it. Before that I had the oil changed at ray skillman 08/20/25 it had 7,720 miles on it then and before that. The very first oil change 22/ may /25 the mileage was 5,354 on it was at hare Chevrolet where I purchased this Blazer rs brand new it had 34 miles I always get the oil changed when it gets to 25%.

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| issues first appeared recorded on 3/9/2026, while odometer read 49,663 miles. Check engine light was caused by error codes p0128 and p01f0. This causes the following issues: * check engine light to appear on the dashboard. * engine temperature gauges to be unreliable at times or completely non functional at others, as it will constantly read the engine temperature "cold". * air conditioning unit to become unreliable at times or completely non functional at others, and only blow hot air. * radiator fan will be stuck running at max speed despite current engine temperature. * a "reduced steering assist" message will periodically appear on the dashboard. * a "service esc" message will periodically appear on the dashboard. * remote start will becomes non functional. | car was taken to a license Chevrolet dealership and had full thermostat housing and thermostat sensors replaced. Dealership confirmed all replaced parts are working correctly and as intended. After picking up the vehicle from the dealership, and driving car for roughly 30 miles, the check engine light appeared on the dashboard again causing all previous issues to return. | several other chevy Blazer 2020 owners have complained of the same issue online, and in forums such [xxx] . | information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

My 2021 chevy Blazer lt v6, has a service bulletin extending warranty on thermostat malfunction, that also causes the fans to run after the car is off. My vechicle was experiencing this issue, went into my local dealer, they claim thats not my issue, I need a new radiator, that has never leaked, or the car running hot. Beyond that the radiator has a service bulletin, they can fail, do to poor quality from supplier, some were replaced under warranty, some were not. This vechicle has 47000 miles, I should not be responsible for this issue. Thank you brett fielding.

The contact owns a 2020 Chevrolet Blazer. The contact stated that while driving at an undisclosed speed, the check engine warning light illuminated. The vehicle was taken to an independent mechanic, where it was diagnosed with vvt sensor failure. The sensors were replaced; however, the failure recurred. The vehicle was taken back to the mechanic, where a solenoid was replaced. The vehicle was repaired. The contact was informed that if the failure recurred, there might be an internal engine failure. The dealer was not contacted. The manufacturer was notified of the failure and referred the contact to the NHTSA hotline to report the failure. The failure mileage was approximately 70,000.

P0128 code. Coolant temperature sensor and thermostat failure.

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When shutting off the car, the fan continued to run. I started the car up again to see if this would allow the fan to turn off. No luck. The steering assist was dis-enabled on the dash. I took my car to the dealer to find out that it has a bad thermostat and that my radiator was leaking. The thermostat was covered but I had to use my extended warranty to pay the additional repair. My deductible for my extended warranty is $300. 00. My daughter has a 2021 chevy Blazer and the same situation happened. There was a recall and all her parts were covered.

Shift to park issue: known issue where the car fails to recognize it is in park, preventing it from shutting off. Electronics: potential blanked-out display screens, usb port issues, and malfunctioning cameras. Steering assist: restricted, temperature gauge goes to cold and radiator fan blows hard. I have to unplug negative cable to battery and reconnect and everything goes back to normal.

Transmission completely failed while driving at highway speeds.

Around 55,000 miles, my 2021 Chevrolet Blazer experienced a throttle body failure. The check engine light illuminated and the vehicle entered a reduced power/limp mode condition. Throttle response was significantly limited, and the vehicle could not accelerate normally. While the vehicle remained drivable, it took substantially longer to reach speed, which could pose a safety risk when merging into traffic or crossing intersections. Diagnostic trouble code p2101 (throttle actuator position performance) was present. A Chevrolet dealer confirmed an internal throttle body failure and replaced the throttle body assembly. This component is a critical engine control system, and failure could affect acceleration and vehicle control, posing a potential safety risk. The failure occurred well before expected service life and required a costly repair. The component has been replaced and is available for inspection upon request. I believe this may represent a premature defect and should be investigated for similar failures in other vehicles. ?.

This submission is an additional report related to NHTSA complaint #11714381. At approximately 55,000 miles, my 2021 Chevrolet Blazer experienced a sudden throttle body failure while driving. The vehicle entered reduced engine power/limp mode without warning and acceleration was significantly limited. This created a safety concern while driving in traffic, particularly when merging and crossing intersections. Diagnostic code p2101 (throttle actuator position performance) was present. A Chevrolet dealer confirmed an internal throttle body failure and replaced the throttle body assembly. Although the repair was completed, this failure occurred at relatively low mileage for a critical engine control component. A sudden loss of acceleration can pose a safety risk depending on traffic conditions. Since filing my original complaint, I have identified multiple similar reports online and in owner forums describing premature throttle body failures in gm vehicles with similar symptoms (reduced power/limp mode and limited acceleration). This suggests the possibility of a broader pattern involving this component. I am submitting this additional report so that NHTSA has a complete record of the incident and potential pattern of premature throttle body failures. If this issue is widespread, it may warrant further review or investigation as it affects vehicle acceleration and safe operation.

For about a week and a half my car had made a high pitched wheezing/hubbing sound when started cold. This occurred at all temperatures cold and warm. Yesterday December 13th I went to run some errands and about a mile into my drive my 2021 3lt 3. 6 v6 Chevrolet Blazer lost the ability to power itself. There was no electrical problem however the power train lost power all gears drive and reverse. I was able to get off the roadway without incident. I scan my check engine light and had several check engine lights including a p 0796.

The contact owns a 2020 Chevrolet Blazer. The contact stated that while driving at an undisclosed speed, the vehicle hesitated with a grinding sound coming from the vehicle, with the check engine warning light illuminated. The contact stated that the vehicle was jerking while driving and while accelerating from a stop. In addition, the contact noticed fuel leaking from the front end of the vehicle while the vehicle was parked at the residence. The vehicle was taken to the dealer, where it was diagnosed that the start/stop accumulator end cap had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA hotline for assistance. The approximate failure mileage was 157,236.

The shift-to-park sensor in my 2019 chevy Blazer rs is malfunctioning. After shifting into park, the vehicle does not detect that it is in park and displays a “shift to park” message. The issue is/has been ongoing and now it is almost impossible to bypass with wiggling the shifter. Safety risk: the vehicle cannot be fully shut off or locked, increasing the risk of battery drain or unintended movement. This poses a safety risk if the vehicle is left in public or on an incline. Inspection history: the vehicle was taken in to the dealership in November/December 2025 due to multiple warning lights: “shift to park”, "steering assist", "stabilink" and the usb-c charging port under the radio screen will stop working all together when this happens as well. This started around September 2025 and has occurred regularly since.

My 2021 Chevrolet Blazer experienced a radiator failure at approximately 42,000 miles. The radiator and cooling system malfunctioned, causing coolant loss and triggering a warning light on the instrument panel. The failed radiator is available for inspection upon request. This defect put my safety and the safety of others at risk because a compromised radiator can lead to engine overheating, sudden loss of power, or even steering assist reduction while driving. These conditions increase the likelihood of an accident, particularly at highway speeds. The problem was confirmed by my Chevrolet dealer, who diagnosed the radiator as needing replacement. They initially quoted $1,800, later reducing the cost to $915. 90 after acknowledging that approximately 20 customers per month at their dealership alone are experiencing the same issue. This indicates the defect is widespread, at least regionally, and may be systemic across the model. The vehicle has been inspected by the dealer service department, which is an authorized gm representative. No police or insurance inspection has occurred. Prior to the failure, a warning lamp illuminated on the instrument panel, alerting me to a cooling system issue. This was the first symptom I noticed before bringing the vehicle in for service. I believe this premature radiator failure represents a systemic defect in the 2021 Chevrolet Blazer’s cooling system. It occurred well within the 5?year/60,000?mile warranty period, yet the dealer claimed the radiator is not covered. I am requesting NHTSA investigate this issue, as it appears to affect many owners and poses a significant safety risk.

Steering assist reduced message followed by check engine light came on and temperature gauge not moving from cold. Immediately took it to the dealership hiley Chevrolet in rockwall, TX. After $250 for diagnostic, failed thermostat is the cause and $1216 repair cost. Known issue that Chevrolet issued special coverage for 2021 Blazers, but none for 2020. My vehicle has a little more than 51,970 miles. Same vehicle just had battery replaced two weeks ago at same dealership and no other issues showed up during diagnostic then.

I backed my vehicle out of the garage and put it in park and stepped out of the driver's door. I was going to put my son in his car seat in the rear seat when the vehicle started moving backwards and the opened driver's door knocked us down. I was able to push my son out of the way, but the vehicle continued and the front left tire rolled over both of my legs. The vehicle continued in reverse along the driveway, struck a trash container and went up the incline at the main road. It crossed a busy two lane road and into my neighbors yard. The vehicle came to a stop about 10 feet from our neighbor's house without striking anything else. We purchased this car used with just under 300 mile on it. During the time that we've owned it, it has randomly flashed a "shift to park" warning lamp on the dash when I shift it to park and turn it off. It has never done what happened to me today. A few months ago, my husband and I took the car to the gm dealership to have it checked out before the warranty expired. We told them about the "shift to park" warning lamp and that the car was shifting hard while driving it. They kept the car a few days and told us they were unable to find anything wrong with it.

Dashboard goes on like a christmas tree (almost all lights turn on abs gas light traction control parking service light) check engine stays on then disappears after a few days. Transmission won’t gear into shifts only stays in one shift.

Automatic transmission and radiator. Vehicle shifted hard and then would not go to a higher gear after pulling out into an intersection. Vehicle was pulled over to side of road and shut off. Restarted and tried to merge back onto main road and while trying to accelerate, the rpm’s went over 3500 quickly and wouldn’t shift once the vehicle hit 30mph. The engine light came on. There has been no previous engine lights or issues. Scheduled an appointment at a Chevrolet dealership and had the vehicle towed on a flatbed trailer to be looked at. I stated that there was a major problem/issue with the transmission and explained the problem. In their notes it states they took it for a test drive before even checking the transmission fluid for metal particles. I told them it was a severe failure and was barely drivable. It was able to drive up in the trailer to be towed, but never shifted out of 1st gear. We are a little over 64,000 miles and the warranty cut off is 60,000. The dealership states that the transmission needs replaced and the cooling system as well since metal particles made it into that system as well.

The contact owns a 2021 Chevrolet Blazer. The contact stated that while her husband was driving 60 mph, the "service engine soon" message was displayed. The contact's husband pulled over to the side of the road. The contact's husband used his personal fixd machine to diagnose the vehicle. The contact’s husband retrieved dtc: p023f (powertrain control module detected a problem in the electrical pathway supplying power to the fuel pump). The vehicle was towed to an independent mechanic who diagnosed the vehicle and determined that the fuel pump had failed. The vehicle was then towed to the dealer. The vehicle has not been diagnosed. The contact related the failure to manufacturer's recall number: n252516900. However, the VIN was not included. The manufacturer was not made aware of the failure. The failure mileage was 90,493.

The contact owns a 2019 Chevrolet Blazer. The contact stated that upon shifting to park(p) and attempting to turn off the vehicle, the message "shift to park" was displayed and an alarm sounded loudly. The contact stated that upon turning off and restarting the vehicle and shifting in and out of park(p) several times, the vehicle responded as intended. The contact stated that the failure had become a recurring failure. The dealer and the manufacturer were not notified of the failure. The vehicle was not diagnosed or repaired. The failure mileage was approximately 65,000.

The transmission in my 2024 Chevrolet Blazer is very noisy often making whining and grinding sounds and I experience rough shifting and transmission hesitation during acceleration or gear changes.

Steering assist reduced warning came on with engine light. When car turned off , radiator fan continued running for a few minutes before turning off. Ac would also not work during this time. Issue has been intermittent. Was told the thermostat was getting stuck open and needs replaced.

I purchased my 21 chevy Blazer in 2024 and had a few problems with a transmission problem. The vehicle would stop and jerk whenever I drove it. I took it to the dealer a few times for repair. They claimed to have fixed the problem, but it started again several months later. The vehicle has approx 82,000 miles on it. I heard that there were some recalls on these vehicles, but not sure if mine is one of them. I feel there are other vehicle like mine that have the same problem.

Temp sensor quit working. I have seen online there are tons of people having this exact problem but no recalls issued.

My vehicle lost complete power while I was sitting at red light. The dashboard went completely out and pop back on stating to put the vehicle in park and push the brake to start. After following those instructions the vehicle failed to start and I left disability until onstar notified mpd to assist. While waiting for assistance I was almost hit 3 times. When mpd arrived on the scene they were able to push the vehicle out of traffic. After my vehicle arrived at the shop I was told the power failure was caused by the malfunction of the DC/DC converter output voltage. I see a bulletin was put out but a recall was my made available. I feel this is a major issue due to the vehicle losing power.

1. The vehicle does not recognize it's in park periodically and will not shut off 2. Thermostat housing and thermostat failure 3. Tint covered chrome on exterior of body peeling off only had the car 3 weeks currently at dealership repairing thermostat out of pocket.

Shift to park error in 2019 Chevrolet Blazer. This has affected numerous vehicles that should be issued a recall and not have to pay over $2500. 00 to fix!!.

I am writing to inform the appropriate authorities of the issues that I’ve continually had with my 2023 Chevrolet Blazer. It has come to my attention that the aforementioned vehicle will need a new transmission and possible engine repair currently totaling at just over 6,000 dollars in repair costs. When I was provided with the total repair cost I was informed by the certified service representative that this was a common issue for the Blazer model and that gm was aware of the ongoing issue. I’ve reached out to gm with my concerns regarding this vehicle and the fact that this is an issue that has in prior dates prompted recalls for Blazer models from the year 2020-2024. I have because of the transmission defects/ failures been stranded and unable to shift gears required for proper motion of the car. To which I am sure you can understand the public safety risk of an inoperative transmission. I have taken the car in for service concerning the transmission on 3 separate occasions within the last 10 days and was told by prior service technicians that “ no problems were visible” leading to the total breakdown of the transmission. I reached out to gm and told them of my wish to return the leased vehicle early due to my fears of now driving and operating the car and was told that I was not eligible for a buy back. Gm is maintaining its stance of no liability and I am seeking outside help from this governing agency to ensure that repair costs are fully covered for this defective product.

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On July 31st 2025 my vehicle would not sift out of first gear. I had vehicle towed to kelly Chevrolet in [xxx] . After a failed repair attempt on August 18 2025 have been waiting on back ordered valve body part number 24045659. No eta on this part even though a transmission replacement would resolve but dealer refuses to replace. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

2023: 16k miles, the Chevrolet Blazer in questions transmission went out; thus requiring it to be brought into the dealership for repair; it was "repaired" and given back to us. A few days after said repair, I was driving it with my son in the vehicle, and the transmission went out while on the highway. I was almost hit from behind as I limped it to the side of the road. A brand new transmission was put in. During this time, there was also issues with the brakes where they were making noises. 2025: Blazer check engine light came on. On the way to get it diagnosed, it began to overheat; we were limping it to the side of the road when it stated "engine overheating, vehicle turning off". The safety system for shutting down when overheating worked, however, I was in the roaad again. Thus putting me in danger of being hit. We just received notice from the dealership that it is (as of this moment) a cooling fan, ac pressure switch, thermostat, and a cracked radiator. We are waiting on the technicians to finish checking it to see if there are any other issues.

The contact rented a 2024 Chevrolet Blazer. The contact stated that while driving at undisclosed speeds, the vehicle vibrated and wobbled. There was no warning light illuminated. The contact stated that while driving at undisclosed high speeds, the vehicle vibrated abnormally. The contact stated that the vibration felt like the wheels were detaching from the vehicle, causing the children's car seats to also vibrate. The contact pulled over to the side of the road. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The rental company was notified of the failure, but no assistance was provided. The manufacturer was not made aware of the failure. The failure mileage was 46,831.