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 federal safety agency Hotline to report the failure. The failure mileage was approximately 70,000.
2020 Chevrolet Blazer transmission complaints
Page 2 of 4: complaints 11 to 40 of 75, newest first, as owners wrote them.
"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)
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
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.
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 federal safety agency Hotline for assistance. The approximate failure mileage was 157,236.
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 the federal safety agency Campaign Number: 20V668000 (Power Train). The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 80,000.
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.
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.
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.
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.
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.
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 federal safety agency Hotline for assistance. The failure mileage was approximately 40,000.
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.
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.
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 federal safety agency Hotline for assistance. The approximate failure mileage was 54,843.
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)
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.
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.
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.
A few months ago had Blazer in for oil change. That same day check engine light came on. Was told thermostat needed to be replaced. Needed to order part. Check engine light went out then steering maybe reduced just a week ago eventually check engine light came on. Took to dealership and thermostat needed to be replaced also radiator developed a leak. Just over 60000 miles
When car is parked and shifted to Park massage is sent put car in Park.was a shifter problem dealer fix for 463.00.58000 mi. 2020 Blazer
The contact owns a 2020 Chevrolet Blazer. The contact stated that the transmission was slipping while driving in the lower gears. The contact stated that the message “Reduced Steering - Drive with Caution” was displayed. The vehicle was taken to the dealer but was not diagnosed or repaired. The contact stated that the failure persisted, and the vehicle became inoperable. The manufacturer was informed of the failure and opened a case. The failure mileage was approximately 50,000.
The contact owns a 2020 Chevrolet Blazer. The contact stated that while attempting to park the vehicle, the shift lever became inoperable. The contact stated that the shift into park message was displayed. The vehicle was taken to the dealer, where it was diagnosed and determined that the shift assembly had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 20,500.
The thermostat is getting stuck open and giving me a reduced steering assist error. My safety was put at risk because of the steering assist being reduced. The problem has not been reproduced but there are many issues online about the same model, year, and mileage all having the same issue. The component is going to be inspected by a service manufacturer. There were no warning lamps prior to error.
What component or system failed or malfunctioned, and is it available for inspection upon request? Multiple components in the engine timing and transmission system have failed. These include: Camshaft actuator solenoid valve failed twice (at ~30,000 and ~60,000 miles), each time with different DTC codes. Camshaft positioning sensor failed, triggering P0024 (“timing advanced and bouncing around”). Timing chain tensioner spring failed, requiring re-timing. Camshaft carrier case gasket experienced a major oil leak at 59,000 miles. Thermostat failed. Battery was replaced, but no diagnostic testing was performed—only code clearing. At 82,000 miles: Torque converter has failed, transmission fluid is tarnished, and the radiator is leaking internally. Yes, the vehicle is available for inspection upon request and has been registered as non-operational. How was your safety or the safety of others put at risk? The vehicle exhibited repeated hesitation, delays when accelerating, and revving while braking. In stop-and-go traffic, it now sputters as if it may stall. These behaviors create unsafe driving conditions, especially at intersections and in congested areas, putting both myself and other drivers at risk. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The torque converter failure and transmission issues were confirmed by National Transmission in Long Beach, CA. Prior component failures were confirmed by Martin Chevrolet, who performed both camshaft actuator solenoid valve replacements under warranty. Multiple DTC codes were recorded and cleared, but no electrical testing was performed. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? The vehicle has been serviced by authorized GM dealerships, but GM did not escalate the issue to their TAC (Technical Assistance Center) or assign a field engineer, in violation of GM's internal escalation policy. No inspections
In March 2025 a Steering assist reduced warning came on briefly. Over the next several weeks intermittent. April 2025 Engine warning light came on. 4-14-25 Went to ToddWenzel Chevrolet for diagnosis to be told the Thermostat needs to be changed and due to a small amount of crystallization on the radiator that as well. I had just had oil changed and fluid levels topped off that morning at Parkway express who did not identify concerns. 4-15-25 brought to Parker Brake who diagnosed and identified there was a glitch that prompted the warning and they can tell that fired when not driving, temp 125Degrees. "it may have been parked cooling down". They noted not need for additional service. Thermostat fine and no evidence of radiator leak. They cleared codes/engine warning. After about a week experiencing intermittent assist reduced warning again. I am understanding that this is a known problem w/ these Blazers and changing thermostat for many does not work. Where does this leave me? GM needs to help with the cost and figuring this out. I am concerned about sudden failure of something while driving that could be unsafe for myself/others.
To whom it may concern, I purchased a new 2020 Chevy Blazer from the dealership five years ago. Since then I have had to replace my battery twice, radiator and now the thermostat all of which have been done at the dealership. The car and all receipts of the repairs are available for inspection if requested. This most recent mechanical issue with the thermostat included the following; fans blowing on high, no AC, check engine light, steering assist reduced message, and temp gauge on C. The car was immediately (same day) taken to the dealership for investigation. Upon inspecting the car the mechanic found the thermostat sticking open and indicated that it would need to be replaced as it was unsafe to drive. A total cost of $1400. It seemed odd that my car is only 5 years old with 75k miles and needing to have the thermostat replaced so I started researching this issue further. I found several complaints on the www.chevyblazer.org forum from other 2020 Chevy Blazer owners with the same mechanical issue. There is one comment on the forum from a mechanic stating that this issue is caused by a faulty wire harness and will continue to cause similar issues until the wiring is fixed. You can find those comments in the forum on www.chevyblazer.org This continues to be an ongoing issue with this make and model of Blazer with no consistent fix from the dealer. I believe my previous battery and radiator issues are all related. I am reaching out to you for assistance and/or guidance to help get this mechanical issue reported as a recall by the dealer and properly fixed at dealer cost. I am happy to provide any additional support you may need to research this further. Thank you in advance.
Coolant temperature would not read, steering assist malfunctioning, air conditioner intermittent. Wiring harness for sensors loomed together with coil pack wiring interrupting signals.
Check engine light came on, gave error code P0128
When putting the car in park the car don’t recognize it’s in park cause the car to stay running.
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