2020 Chevrolet Blazer Powertrain (other) Problems

Last year I was heading to heading to [XXX] in XXX when I pushed on the brakes on my 2020 Chevy blazer my brakes were working but the steering wheel was shaking weird like I was hard on the brakes but I was tapping them slowly earlier this year right before I had transmission flush at fox Chevy in Caledonia I noticed before two weeks of bringing it in I was near a traffic light slowing down it went hard shift down and when I was not moving in notice it jerked forward when at idle and the light like it was rear ended I feel like this is a safety concern of that happening after the transmission flush for two months after doing the acceleration is slipping I feel like there should be a recall for torque and transmission recalls for the 2020 Chevy blazers I really love this blazer owned for 4 years now I feel like it would be a safety for the public and nationwide INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11749874

Incident

Apr 7, 2026

I am submitting this complaint regarding the transmission in my 2020 Chevrolet Blazer. My vehicle has fewer than 100,000 miles and has experienced significant transmission failure symptoms, including hard shifting, jerking during acceleration, RPM fluctuations, slipping, loss of normal power, and inability to safely reach highway speeds. The vehicle struggles to accelerate properly and at times will not shift correctly into higher gears. Diagnostic trouble codes related to transmission operation have been present, including pressure control solenoid and transmission control faults. Repairs have already been attempted, including replacement of transmission-related components, but the transmission continues to malfunction. Through online owner groups, forums, and discussions with other Chevrolet Blazer owners, I have found numerous reports from owners experiencing similar transmission problems in 2019-2022 Chevrolet Blazers. Many owners report transmission slipping, harsh shifting, torque converter issues, valve body failures, pressure control solenoid failures, and complete transmission replacement at relatively low mileage. These failures create a serious safety concern because the vehicle may hesitate, lose power, fail to accelerate properly when entering traffic, or be unable to maintain safe highway speeds. Drivers and passengers are placed at risk when a vehicle cannot respond normally during merging, passing, or other traffic situations. Owners are frequently being quoted between $7,000 and $12,000 for transmission replacement or repair despite the vehicles being relatively new and often having less than 100,000 miles. Many consumers believe these failures indicate a widespread defect rather than normal wear and tear. I request that NHTSA investigate transmission failures in the 2020 Chevrolet Blazer and related model years to determine whether a manufacturing or design defect exists and whether a recall or other corrective action is warranted.

NHTSA ID

11744816

Incident

Apr 6, 2026

I am submitting this complaint regarding my 2020 Chevrolet Blazer and what appears to be a widespread cooling system defect. My vehicle has developed a coolant smell outside the vehicle, which raises concerns about a coolant leak from the radiator. After researching the issue, I discovered that numerous Chevrolet Blazer owners have reported similar coolant-related problems, including radiator failures, coolant leaks, and persistent coolant odors. These complaints are widely discussed across online forums, social media, and owner groups. General Motors appears to be aware of this recurring issue, yet many owners continue to experience failures within and outside of warranty coverage. The coolant smell is concerning because it may indicate a leak within the cooling system, which could lead to overheating, engine damage, loss of vehicle reliability, and potential safety risks while driving. Owners should not be experiencing major cooling system failures on relatively modern vehicles. I request that NHTSA investigate the cooling system and radiator issues affecting the 2020 Chevrolet Blazer and determine whether a defect exists that warrants a recall or other corrective action. The number of similar complaints suggests this may be a systemic issue rather than isolated incidents. General Motors should be held accountable for addressing this widespread problem and providing a permanent repair solution for affected owners. Thank you for your attention to this matter.

NHTSA ID

11743467

Incident

Jun 1, 2026

Engine temp gauge stops working causing the air to stop working and the cooling fan to rev to highest rpm. Also a warning that the steering assist is reduced. Eng check light comes on with a code P0208. This a known problem with an extended service # (N242484760) but only if your vin is listed. All vehicles with this problem should be covered

NHTSA ID

11740390

Incident

May 27, 2026

| 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 as: [XXX] . | INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11729613

Incident

Mar 9, 2026

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!!

NHTSA ID

11724826

Incident

Mar 16, 2026

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.

NHTSA ID

11718743

Incident

Feb 18, 2026

Mileage

70,000 mi

"I was in extreme danger while traveling with my [XXX] child in the vehicle on the day prior to the total failure. During that trip, the transmission began to slip significantly in active traffic, creating a terrifying loss of motive power and a high risk of a rear-end collision. Because of this dangerous incident, I attempted to reach the dealership the following morning to prevent a crash. Upon arrival, the transmission suffered a total catastrophic failure in the dealership lot. Had this final failure occurred just 24 hours earlier while my child was in the vehicle on the highway, the situation could have been fatal. The vehicle is currently inoperable due to the 'check ball' metallurgical defect (RO #XXX). INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11713817

Incident

Jul 20, 1988

Car is cutting off while driving , I’m driving on a busy road , engine jerks and stall out leaving me with no power to accelerate. Brakes work but gas pedal not so much . I have to cut off the car hoping it turns on , cause it don’t want to turn over once I decide to turn it off

NHTSA ID

11708234

Incident

Aug 14, 2024

Where do I start. Spring of 2024 I believe, less than 55,000 miles, my transmission went out. No warning. I just went out to my vehicle to go to work and when I put it into reverse, my vehicle make a awful noise, jerked forward almost going into my garage door, then wouldn't move.. I put it back in park, tried to put into reverse again and it wouldn't go. It was stuck in park. Had to get it towed to the dealership where they advised me the transmission went out. It was covered under the drivetrain warranty, but the GM warranty doesn't cover rental. It took almost 4 weeks for GM to approve for a new transmission due to parts being on back order to rebuild my transmission. Several months later, I was driving down the road when the ESC light and then it said "shift to neutral & press start" and I lost power. I coasted into a parking lot, got it fired up, but had no air conditioning (of course it was summer). Took it to the dealer and they said my radiator and A/C Compressor had to be replaced. Luckily my extended warranty covered the $5000 repair. Now 4 months later I got "steering assist reduced, drive with care" with codes. Took to shop and the codes basically was the temp was to low, but the shop couldn't find anything wrong. Cleared the codes and so far so good, but now my ESC light pops on once a week again. I don't even have 60,000 miles on my vehicle.

NHTSA ID

11705481

Incident

Apr 1, 2025

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.

NHTSA ID

11704538

Incident

Dec 11, 2025

Mileage

157,236 mi

The contact owns a 2020 Chevrolet Blazer. The contact stated that while attempting to start the vehicle, the brake pedal was depressed, but the pedal was firm, and the contact was unable to start the vehicle. The vehicle was towed to the dealer, where an unknown repair was performed. Additionally, the contact stated that upon taking the vehicle for an oil change, the contact was informed that the service could not be performed because the rear main seal was defective. The vehicle was taken to the dealer, where the contact was informed that the rear main seal was in good condition. The dealer informed the contact that the transmission had failed and that there was a hole in the transmission. The dealer repaired the transmission. The contact related the failure to NHTSA Campaign Number: 20V668000 (Power Train). The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 80,000.

NHTSA ID

11702406

Incident

Jun 2, 2024

Mileage

80,000 mi

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.

NHTSA ID

11700067

Incident

Nov 13, 2025

Component/System Involved: The shift-to-park sensor in my 2020 Chevy Blazer is malfunctioning. After shifting into park, the vehicle does not detect it and displays a “Shift to Park” message. The issue is ongoing, and the component is available for inspection if needed. 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 has not been inspected Warning Signs: The “Shift to Park” message appears when trying to turn off the vehicle, despite the gear being in park. This started around Fall 2024 and has occurred regularly since.

NHTSA ID

11694202

Incident

Sep 1, 2024

Received Error code P0021 "A" camshaft position timing is over-advanced in Bank 2 of the engine" Occured 3 times before taking it into dealer. Chevrolet dealership agreed and it was covered under powertrain warranty.

NHTSA ID

11694201

Incident

Jan 1, 2024

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.

NHTSA ID

11692355

Incident

Oct 9, 2025

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.

NHTSA ID

11687550

Incident

Sep 3, 2025

The contact owns a 2020 Chevrolet Blazer. The contact stated that while parking the vehicle and shifting to park(P), the message "Shift to Park” was displayed. The contact turned off and restarted the vehicle several times and shifted from drive(D) to park(P) several times before the message disappeared. The contact stated that the vehicle was also showing electrical failures. The contact stated that after shifting to park(P) and turning off the vehicle, the contact heard chimes as if the vehicle was still running. There was no warning light illuminated. The contact stated that one morning the vehicle had to be jumpstarted and on another morning the battery was completely drained. The battery was taken to an Auto Parts Store to be checked. The contact was informed that the battery was in good operating condition. The contact stated that the battery was drained again and was replaced. The contact had not taken the vehicle to a local dealer or independent mechanic to be diagnosed or repaired. The manufacturer was informed of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 40,000.

NHTSA ID

11686391

Incident

Jun 23, 2025

Mileage

40,000 mi

Frequently when shutting off my Blazer, I will get an alert that the vehicle is not in park. I have to squeeze and jiggle the shifter in order to get the alert to go away. On several occasions, when I have turned the engine on and back off again without ever touch the gear shifter, I will get the same alert that the vehicle is not in park. If the issue is not just the sensor/switch, this could mean that the transmission could potentially fall out of park and the vehicle start to roll on its own with no one inside.

NHTSA ID

11686239

Incident

Mar 1, 2025

On multiple occasions, my 2020 Chevrolet Blazer RS has failed to recognize when it is shifted into the "Park" gear. When this occurs, a "Shift to Park" message appears on the dashboard, and the vehicle's electronics will not shut down, preventing me from turning off and locking the vehicle. This defect presents several critical safety hazards: Inability to Secure Vehicle: The engine/electronics remain active, preventing the vehicle from being turned off and secured. This could drain the battery, leaving me stranded, or make the vehicle a target for theft. Driver Distraction: The warning message has appeared randomly while the vehicle is in motion, creating a serious and unexpected distraction for the driver. Potential Rollaway Risk: This failure in the system that confirms the vehicle is in Park could lead a driver to exit the vehicle believing it is secure when it is not, creating a potential for a vehicle rollaway. On 05/02/2024, I had the vehicle serviced for this specific issue. The dealer replaced the transmission shifter and control assembly at my expense, refusing to cover it under the powertrain warranty. The manufacturer (General Motors) is aware of this widespread defect and has issued Technical Service Bulletins (TSB #MC-10199243-9999) about it, yet they fail to treat it as the serious safety issue it is. This component failure should be investigated for a formal safety recall before it leads to an accident, injury, or death.

NHTSA ID

11684500

Incident

May 2, 2024

The contact owns a 2020 Chevrolet Blazer. The contact stated that while attempting to park the vehicle, the gear shifter was shifted into park. The message “Shift to Park” was displayed while attempting to restart the vehicle. The dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA Hotline for assistance. The approximate failure mileage was 54,843.

NHTSA ID

11679101

Incident

Aug 7, 2025

Mileage

54,483 mi

I am experiencing the well known "shift to park message" while the shifter is in park. I cannot turn the vehicle off and I am worried the battery will die. This is a well documented issue with this vehicle, and several other models outlined in TSB 19-NA-206, for years and yet they refuse to issue a recall to repair the faulty design or component . I have reached out to them via email, but no action has been taken, see email below. ------------------------------------------------------------------------------------- GM Customer Care, I am writing to request assistance regarding an issue with my 2020 Chevy Blazer VIN# [XXX] . This is my fourth new GM vehicle, and while it is currently outside the 36-month warranty period, the vehicle has only 18,800 miles on it. Recently, the vehicle began displaying a persistent "Shift to Park" message on the Driver Information Center, despite the gearshift being in the Park position. As a result, the vehicle remains in the ON position and cannot be turned off. This is a well-documented issue affecting several GM models, including the Blazer, Acadia, Malibu, Traverse, and Volt. For reference, please see TSB 19-NA-206 attached. Repair costs for this issue appear to vary widely, sometimes exceeding $1,000 depending on location and dealership. Given that this appears to be a known design or component issue, I do not believe this should be an out-of-pocket expense for the customer. As a long-time GM customer, I respectfully request that GM cover the cost of this repair. I am disappointed that there has been no proactive recall or service campaign, especially considering the volume of customer complaints reported online. Thank you for your time and attention. I look forward to your response and hope GM will stand behind its products in this matter. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11672407

Incident

Jun 2, 2025

The contact owns a 2020 Chevrolet Blazer. The contact stated that while his wife was driving 80 MPH, the vehicle failed to accelerate as intended while depressing the accelerator pedal. In addition, the contact stated an abnormal sound could be heard coming from the engine. The vehicle stalled and the contact's wife was unable to move to the side of the road. The message "Shift to neutral and press the start button" was displayed. The police assisted with traffic control while the vehicle was pushed to the side of the road. The vehicle failed to start. The contact stated that prior to the most recent failure, the gear shifter would be stuck in park(P). The contact would move the gear shifter several times to cause it to move. The contact stated that the failure recurred several times, and the vehicle responded as needed after several attempts. After several attempts, the check engine light was illuminated. The vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure and referred the contact to the NHSTA Hotline for assistance. The approximate failure mileage was approximately 40,000.

NHTSA ID

11669576

Incident

Jun 26, 2025

The contact owns a 2020 Chevrolet Blazer. The contact stated upon shifting to park(P) and attempting to turn off the vehicle, the message that the transmission was not in park(P) was displayed. The contact stated that the failure recurred several times, and the vehicle responded as needed after several attempts. The dealer was not notified of the failure. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 38,000.

NHTSA ID

11667110

Incident

Jun 2, 2025

Mileage

38,000 mi

My vehicle has been throwing an error code related to the thermostat. The temperature gauge will remain on C resulting in the fan running loudly, the air conditioner not cooling the cabin of the vehicle well, and a message displaying "steering assist is reduced drive with care". When I check the fluid levels everything is fine without issue. I'm VERY frustrated and want to get rid of my Blazer ASAP.

NHTSA ID

11667096

Incident

Dec 12, 2024