2020 CHEVROLET BLAZER Power Train Problems

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.

"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 &...

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 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...

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.

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.

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.

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...

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.

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.

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...

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....

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.

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...

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...

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.

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.

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...

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...

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...

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.

Cooling ran would never shut off, 'Steering Assist Reduced Drive with Care', the smell of sweet syrup (coolant), and the temp gauge would not leave 'C'. All of this happened at once. Brought it in as it was subsequently throwing codes. Chevy Heiderbrecht dealership said that the radiator seal at 53k is completely eroded away and needs to be replaced. They said this is a very common issue with these cars (2020 Blazer/Original Owner), and looking online there is a plethora of people with the exact same issue (low mileage, complete radiator replacement due to seal going bad on upper driver side). This is insane, you spend 40k on a car, maintain it well, and the parts fail this prematurely with no available recall? Now I am stuck with an $1,800 bill with no legal recourse? I mean the dealership said it is a widely known issue, and GM has...

On Saturday, March 8, 2025 I was crossing a busy intersection when my car shut off completely and accelerated into oncoming traffic almost causing a collision or fatality. My brakes locked and steering wheel locked. I had to put the emergency brake on in order for the car to come to a stop. We got out of the car in the middle of the street and ran for safety. Scariest experience I’ve ever been in especially with my family in the car!!

Continues "reduced steering assistance', thermostat won't register, stay on Cold, a/c blows warm air. We added coolant, replaced battery. Code goes off, within a few weeks comes back on. About to replace the whole thermostat and sensor. Many many blazers having the same issues.

The contact owns a 2020 Chevrolet Blazer. The contact stated while attempting to shift to park, the engine remained running, and the message "Shift to Park" was displayed. A mechanic was called to diagnose the vehicle, and the contact was informed that the transmission control, shifter harness, inline shifter wiring harness jumper, park switch, and other related components were faulty and needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 77,340.

At around 55,000 miles my Blazer began to show error codes for “Steering Assist Reduced” and “ESC”. After 60,000 it began to intermittently populate the Check Engine Light paired with the "Steering Assist Reduced" message. Then, the engine fan would turn on high, auto-start when breaking would disable, and the steering would become more stiff. Finally, I was able to get a scan on the code and found out that it was my thermostat. After taking it to my local Chevy dealer I was quoted $1100 to repair. When I called my local mechanic I was told they could fix it for cheaper, but they were unable to find an OEM thermostat in stock which usually means there's a widespread issue with that part. Upon further research, I've found a plethora of complaints online where others with Chevy vehicles are experiencing the same issue. This causes: -Greater fuel consumption -Risk...

Questions Answered Below: What component or system failed or malfunctioned, and is it available for inspection upon request? The vehicle is at a GM Dealership now and is available for inspection. I have not authorized repairs as of yet. I am being told by the dealership: The ball joint on the control arm on the left side seized snapping the axle shaft - causing the tire to to turn out. The dealership has suggested: Mechanical repair costs $1,850, Plus an additional $2,000 due to wheel well damage caused by the failure. Has the problem been reproduced or confirmed by a dealer or independent service center? I am being told by the dealership: The ball joint on the control arm on the left side seized snapping the axle shaft - causing the tire to to turn out. How was your safety or the safety of others put at risk? Due to...

P0128 code- Assisted steering fault Check engine light Ac blowing cold Temp gauge flat lined Need to replace temp sensor and thermostat. Others with this issue have reported steering can completely lock up, which could cause serious accidents which could result in fatalities.

I am getting the message "Shift to Park" displayed while vehicle in park after turning the vehicle off. Looking online, it seems to be a common issue with Blazers as well as other GM vehicles. I found online that "the cause of the condition may be that the park switch in the transmission control (shifter) assembly is not pulling the BCM signal low to electronically show that the vehicle is in the Park position." If this is such a common issue on similar vehicle to mine since 2018 it appears, why is this not a Recall already?!

When you shift it into park, it often doesn’t recognize that it’s in park and begins to roll backwards. This doesn’t happen every single time but at least twice a week and I have to use the parking break.

2020 Chevy Blazer - Shift to Park while Gear is already in Park: While putting the gear in park, the warning chime to shift it into park is initiated. It has happened 3 to 4 times in the past three days. I took the vehicle to the Local Chevy Dealership. The Service Team/Dept. diagnosed that the Transmission Shifter Unit Assembly must be replaced. The 2019 Chevy Blazer had these issues which prompted a TSB/Recall however it wasn't extended to the 2020-year models and Chevy Dealership refused to include it as a warranted repair which just passed 44,000 miles. This is a safety issue, and it should be replaced without additional cost to customer as this issue was already identified as a safety concern in 2019, however Chevy does not want to identify the issue as a covered repair per the manufactures warranty.

The contact owns a 2020 Chevrolet Blazer. The contact stated while the vehicle was parked in the driveway, the vehicle hesitated. The contact stated that while attempting to turn off the vehicle, the vehicle independently shifted out of gear. The vehicle was driven to the local dealer to be diagnosed. The dealer determined that the failure was a power train failure. The vehicle was not repaired. The manufacturer was notified on the failure. The approximate failure mileage was 49,000.

The contact owns a 2020 Chevrolet Blazer. The contact stated that upon arriving at his destination, the vehicle failed to detect that the gear shifter was in park(P), preventing the vehicle from being turned off. The contact stated that the message "Please Shift to Park" was displayed. There were no warning lights illuminated. The vehicle was not taken to the dealer or an independent mechanic. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 50,000.

2020 Chevy Blazer- bad transmission at 130,000 miles

My shift to park comes on although the vehicle is parked My steering is reduced came on today this is a problem in mutiple forms in regards to chevy blazers

When I put the car in park it does not register and will not come out of accessory more. This is a known issue and gm is making customers out of warranty pay for it

When placed in park the DIC will intermittenly indicate "Shift To Park". At that point, I am not certain whether or not the vehicle is in park. It will often go into accessory mode when this happens. I cannot turn the vehicle completely off at this point. I need to shift it from park to reverse or drive and then back into park. It may take several attempts for it to register that the vehicle is actually in park. The problem is occurring more and more frequently over time. I am about to take it to the dealer for repairs. I believe this is a common problem with many GM vehicles and they ought to fix it under a recall notice.

The contact's wife owns a 2020 Chevrolet Blazer. The contact stated that on several occasions when the vehicle was shifted to park(P), the message “Shift to Park” was displayed. The vehicle was not taken to be diagnosed or repaired. The manufacturer was notified of the failure. The failure mileage was approximately 8,000.

Intermittent Shift to Park Message Displayed While Vehicle in Park. I am seeing an intermittent Shift to Park message when the vehicle has been shifted into Park, and the ignition has been turned to the Off position. My car model is a push-to-start/stop ignition type and this issue prevents me from turning off the car at times. I am having the vehicle serviced currently at my local chevrolet dealership but being subject to a diagnostic fee of $175. A message shows up on the instrument cluster screen stating "Shift to Park," however, the shifter is already in the Park position. Potential cause: The cause of the condition may be that the park switch in the transmission control (shifter) assembly is not pulling the BCM signal low to electronically show that the vehicle is in the Park position.

This vehicle is currently on its third radiator since it was purchased, 4 years ago. That’s almost 1 radiator per year. The vehicle also has transmission issues on the highway. The dealer replaced the torque converter but vehicle is still hesitant and bucking on the highway. This vehicle only has 64,000 KM and would cost thousands in repairs if it wasn’t under warranty.

Steering assist reduced warning came on as I was driving. Electric steering module has gone bad.Temp gage and AC stopped working as well. No accident yet but this is a KNOWN SAFETY DEFECT that needs to have a recall. The steering wheel could lock up. Force GM to recall this vechile before people die!!