2020 CHEVROLET BLAZER Engine Problems

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

The thermostat failed on a trip locking in 0 temperature reading and steering assist warning. Licensed mechanic repaired on 10/9/25 invoice is available. 67,509 miles. This could risk overheating and destroying the engine and might cause accident. Two other friends have had similar issues, appears to be a safety defect!

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.

Thermostat/thermostat sensor and complete water outlet system replacement at only 52,377 miles. The defective part was located under the Intake Manifold requiring its removal, excessive labor cost for the repair, and potential future engine issues due to exposed/open head gasket for the repair.

2020 Chevrolet Blazer, 19900 miles, lightly driven The radiator seam is leaking coolant, which appears to be a known issue as there are numerous complaints on various websites and forums. The vehicle is now unreliable due to an overheating risk.

Warning message indicating steering assist system reduced, engine fan running non-stop, AC blowing hot air, temperature gauge not registering/stuck on cold. Faulty engine temperature sensor and thermostat.

"Steering Assist Reduced” warning message appears on dashboard display and temperature gauge stuck on cold on the dashboard display. I understand this such a common issue with the 2019 and 2020 Blazer that General Motors has issued Technical Service Bulletins but refuses to repair these vehicles for free. This is unacceptable! Issue a mandatory recall therefore GM must perform the repairs for free.

Engine light on, power steering assist, air conditioning stop working diagnostic tool read p0128 coolant thermostat

The original issue was that the temperature gauge was pegged on cold and the A/C was inoperative. The vehicle’s fans would run continuously even when the engine was cold. This created a safety concern since the engine’s actual temperature could not be monitored, and loss of A/C affected drivability in hot conditions. The issue appears related to the engine’s coolant temperature sensor or thermostat system, which causes incorrect signals to the temperature gauge and HVAC system. The condition has been reported by multiple owners of the 2020 Chevy Blazer 3.6L. In my case, the malfunction happened suddenly and has been repeatable. There were no prior warning lamps until the issue occurred, at which point the temperature gauge stopped working properly and the air conditioning failed.

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.

Check engine light on, message saying "steering assist reduced drive with care", engine temperature gauge not moving from C, and AC not working. I have taken it in to be fixed 3x, and they have fixed it 2/3 times but the message has come back again. It is a big issue in 2019/2020 blazers according to my research.

I purchased this vehicle in March, 2025 from a used dealer. When I got it, I noticed the vehicle was leaking oil on my garage floor. I took it back to used dealer who also agreed there is a leak but couldn't detect it. They sent me to Chevy Dealer. It has been 3 months now and dealer states the transmission has a seal leak. It seems like a similar recall on same year and model, however my vehicle is not listed as a recall. Why isn't there one?

The contact owns a 2020 Chevrolet Blazer. The contact stated while driving approximately 45 MPH, the instrument cluster went black, and the vehicle stalled. The contact stated that there was no warning light illuminated or an audible chime heard. The contact stated that several attempts were needed to restart the vehicle. The vehicle was restarted, and the message "Vehicle in Transport Mode" was displayed. The contact stated that the failure was intermittent but reoccurred. The contact stated that the vehicle was not taken to a 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 92,000.

Mileage: 92,000

The blazer's check engine light came on and I had it scanned. The code was PO128 indicating that the engine coolant temperature is consistently below the thermostat regulating temperature. We are also getting a message on the vehicle that states the steering assist is reduced, drive with care. The car is also blowing hot air when the AC is on, the temperature gauge is staying at the lowest setting and the fans are running full blast. This seems to be a very common problem with the Chevrolet Blazer.

I have an oil leak and now they are saying both of my camshaft housing gaskets are leaking it's going to take weeks to repair cause it's such a major leak

Vehicle gives warning that steering assist is disabled. I should drive carefully. Also cooling fans run on high and temp gauge reads zero. P0128 I'd code given by computer. When code is cleared vehicle returns to normal operation. I read many, many people have this same problem with no clear correction. Many have replaced thermostat, temp sensors, and problem returns. Sounds like defective wiring to me and if it impacts steering should be an OEM problem to remedy

To Whom It May Concern, I am writing to formally file a complaint regarding ongoing and persistent issues with my 2020 Chevrolet Blazer. The vehicle has exhibited repeated problems that I believe may indicate a broader safety or mechanical defect, and I am requesting that the NHTSA investigate these concerns further. Since purchasing the vehicle, I have experienced the check engine light turning on and off repeatedly, without consistent resolution. The following issues have occurred over time, all seemingly related to the engine or control systems: Engine Cooling System Failure: The first major issue involved the engine cooling system. This caused the vehicle to overheat and required service. I was concerned about the potential for engine damage or fire risk due to excessive heat. Variable Valve Timing (VVT) System Malfunction: Shortly after the cooling system issue, the vehicle began experiencing problems with the variable valve timing system. This not only affected performance and fuel efficiency but also caused the check engine light to illuminate again. Steering Control Assist Sensor Warnings: Most recently, the steering control assist sensor has started to malfunction, with warnings frequently popping up on the dashboard. This has impacted steering feel and raises serious safety concerns. Despite multiple service appointments and repairs, these problems persist or reappear. This cycle of temporary fixes without a lasting resolution is both frustrating and concerning from a safety standpoint. I am requesting that the NHTSA look into whether these recurring engine and control system issues are part of a known defect or recall-worthy problem affecting the 2020 Chevy Blazer. Thank you for your attention to this matter.

Car gets “assisted steering is turned off. Drive with caution.” Warning, temperature gauge in vehicle remains at zero/cold. Engine fan runs at full blast. Sensor gauge/thermostat is broken.

Ongoing Engine and Steering Sensor Issues – 2020 Chevrolet Blazer I am filing a complaint regarding repeated safety and mechanical issues with my 2020 Chevrolet Blazer. The vehicle’s check engine light frequently turns on and off, and I have been informed by technicians that it is related to the thermostat system. This issue negatively affects the vehicle’s performance and reliability. Additionally, the “Steering Assist is Reduced – Drive with Care” warning continues to appear while driving, even when weather and road conditions are normal. This error is reportedly due to a steering control assist sensor, and it raises serious concerns about the safety and handling of the vehicle. The alert causes uncertainty and could potentially impact the power steering functionality, creating a hazardous driving situation. These issues have occurred multiple times despite maintenance, and they appear to be part of a broader pattern of defects affecting other owners of this model year. It is unacceptable for a vehicle this new to have persistent problems that affect both engine operation and steering safety. I urge the NHTSA to investigate these recurring issues with the 2020 Chevy Blazer’s thermostat system and steering assist sensor to determine whether a recall or manufacturer intervention is warranted. Safety should not be compromised due to what seems to be systemic defects. Thank you for your attention to this matter.

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

Failure of either coolant temperature sensor or thermostat or both. The A/C is disabled, the temperature gauge does not function, and a message appears on the dash display regarding steering assist not working. With all these issues, it’s impossible to feel safe driving any distances, not knowing whether the vehicle will overheat and damage the engine or other components, or if the steering will actually fail. Both parts have been replaced, at the time, May 4, 2025.

The thermostat has failed, causing hot air to blow into the car. This is a known and common issue with the 2020 Blazer.

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.

Engine fan stuck on high, air conditioner does not work, temperature gauge stuck on cold, driving assist warning light on.

I have had to replace the radiator 3 times since I've owned this vehicle. I see where there are others with the same issue. Now I have to replace the thermostat my first radiator was replaced at 16k miles. This is a safety issue because my car over heated and broke down on the highway left me stranded

Chronic code P0128, causes cooling fans to go on high, AC doesn't work and steering assist reduced. GM calls for the thermostat to be replaced, at the cost of $1400 at my local Chevrolet dealer. Worked fine for two months then code and issues come back. Online forums are full of people with the same problem. Clearly there is an issue with these vehicles with the 3.6l motor.

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.

Radiator was found to be leaking. Now thermostat is sticking. This could have caused my engine to overheat and catch fire. I have had a mechanical shop replace the radiator but could not afford to replace the thermostat yet. I had been seeing warning lights and still see warnings after radiator was replaced. They said “Steering Assist Reduced” and “ESC” and the engine light came on. I went to Auto Zone Dec 9th to have them tell me what was wrong. I took to shop on Dec 13th. I have googled several complaints about Chevy blazers having this particular problems. This is apparently a widespread issue that needs to be recalled.

Steering assist warning and engine check light are on. I had an scan done and was told it was the thermostat and coolant temperature sensor which seems to be a common problem. There are no safety concerns to my knowledge. I feel this problem needs to be addressed as repairs are very costly.

The 2020 blazer is having the same coolant temperature problem the 2021 blazer has and the recall needs to be expanded. Thermostat messed up, constantly losing coolant, check engine light, steering reduced

Thermostat is faulty at 55k miles. Purchased 2020 Blazer RS, certified used from Chevy in October 2023. Less than 1 yr later, thermostat is stuck on cold, no ax or heat, drivers assist reduced notice. Same issues as previous documented complaints. The frustration is why this known issue is not covered under warranty or recall! I just had my 50k maintenance service done while this issue was occurring- service told me “well we cleared the codes” , 2 days later check engine is on, temp stuck on cold, fan is over worked and no a/c or heat- and driver assist turns off. The safety issues around causing more engine damage by improper cooling and reduction of driving assistance. Additionally, parking issue with vehicle not recognizing it’s in park and having to wiggle or jam the shifter- car drains battery and won’t lock until resolved. Car is took expensive to have a $1200 replacement not covered under warranty!

2020 Chevy blazer with 50,000 miles just had to have the thermostat housing replaced. Check engine light would everntually come on. But it would say "Steering assist reduced drive with care" When hooked up to the computer it read code P0128. I have the extended warranty and still had to pay over $600 to have this fixed which is completey ridiculous for how new and expensice this car is.

Shift to park issues. Car not reading that it’s in park.

6/12/2024 In Damon Parking lot in Rochester MN. Going less than 10 miles an hr- cars in front of me and behind me looking for a parking spot. Stop and go at times. Went to turn corner to go from one level to the next and my BLAZER took off "like a bullet". No control over accelerated speed- hit outer cement wall and slammed into 2 parked empty SUVS. Could not go any farther. The 2 SUVs slammed into cement wall in front of them. Injuries to both my passenger and myself. I have no idea what happened - it was so fast- I do know I had no control over accelerated rate causing accident. My 2020 Chevy Blazer was totaled- It was inspected by American National Insurance CO. Absolutely no warnings. Police report did not include any witness. Blazer is in the hands of the Insurance Co. Chevy Blazer took off like a bullet - could not stop it!!Police report 24026393 Rochester Police Dept Unable to upload . Checked no police report below so I could continue report.

Esc message on dashboard & all wheel drive disabled & lane assist traction control liggt turns on & parking brake light turns on while driving caused for my electric component to act all crazy including my sunroof I’ve been in the dealer over over try to fix it and that is concerning reason for my safety while u are driving and all those lights come on And yes I have took it to the dealer multiple times to fix this situation And yes the vehicle has been inspected by the manufacturer And yes it has happen before i have a 1 year with the car the problem first came about couple month after I got the car and been having problem since then I bought the car 5/13/23

Approximately three weeks ago, our 2020 Chevrolet Blazer's check engine light came on. It has a little over 63,000 miles on it. I took it to a private service garage where they diagnosed the code as P0128, or coolant system issue. They concluded that it was the thermostat. I did some checking on the warranty and it turns out that the warranty on this car expired at 61,066 miles. I then took it to Serra Chevrolet in Grand Blanc, MI where they diagnosed the same error code, or P0128. They took the car back to give me a service estimate and when they returned they diagnosed not only the thermostat as defective. This has become a common problem with this car and the 3.6 liter engine in particular. We have been told that this is a "known issue" by two different General Motors dealerships, specifically in their respective service departments. However, the owners are now having to pay for the complete replacement, both parts and labor, for these issues. Given the fact that these are a known issue, it seems to me that these need to be elevated to at least a bulletin, if not a full recall. The repair and replacement for the thermostat and sensor is in excess of $1,000. Again, since this is a known issue, it is my belief that General Motors should pay these expenses.

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.

The "steering assist reduced; drive with care" notification began coming on the dash with significant changes in outdoor temperature, as of last fall 2023. The temperature gauge on the dash would then not work and would remain at cold. Eventually the check engine light will come on however all of this will clear when the outdoor weather is stable again. As I live in MN you can imagine there are many variations to our temperatures. This occurred at the beginning of fall 2023, then winter 2023, then spring 2024. It is clear from consult with mechanics that this is all related to the thermostat being stuck open/closed. This is a very well documented issue for Blazers and I would even refer you to [XXX] which has pages and pages of both concerns related to this issue as well as radiator cracks; which I am dealing with also. This car has less than 60,000 on it! The radiators are also obviously faulty in these Blazers as well given the amount of people needing to replace these before 60,000. Some even reporting replacement under 30,000 miles which is ridiculous for a $52,000 vehicle. I would also direct you to a Facebook group of Blazer owners and the complaints about these two issues are rampant. (2019+ Chevy Blazer Official Group) [XXX] I had an appointment at Rosedale Chevrolet in MN on [XXX] and after diagnostics, and all of the above was confirmed. This issue poses a safety risk given the potential impact to the steering assist, air conditioning in hot temperatures, the car overheating and engine damage which WOULD be covered under the powertrain warranty, as well as the potential of being stranded due to a break down. This issue appears to be primed for a class action lawsuit. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

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!!

Transmission issue, computer repair, constant issues.

My vehicle needs a new purge pump which is part of the emissions system. This is a common problem on this vehicle so it should be covered by GM since it is part of the emissions system.

The car repeatedly has an error pop up that states steering assist is no longer activated and to drive with caution. The thermostat during this is also fully on cold. The check engine comes on after. The sensor and thermostat are repaired based on the code and problem persists. Same problem all over forums but Chevy refuses to fix as no recall. This is very concerning as the car may randomly go into limp mode while driving on the highway at 70mph putting at risk for crashing. The steering assist is also out putting at further risk. This is despite fixing and clearing the codes shown. This is a known issue that Chevy is refusing to address/recall.

I was driving on express way 96W Left lane busy 5 o'clock traffic Car just died it was stop n go I could have been killed if it wasn't for a man that stopped behind me he couldn't help another person stopped and push the car in N To a grass area where at least I wouldn't be smashed in Called 911 state police inform help van He didn't look at it my friend was there to pick me up Called tow truck they dropped it off at Chevy dealership in Howell Mi

My 2020 Chevy Blazer began demonstrating possible problems with the transmission in November 2021 which have continued to date. The RPMs will rapidly increase and the car will feel as if it is jolting forward. If driving below 20 mphs, when I try to accelerate to a higher speed, the car will drag and then skip forward. I have videos showing this and have taken it to the dealership on two occasions but it couldn't be replicated and no codes show during diagnositics. The car is currently being repaired (at the dealership since 3/18/22) due to 3 separate concerns that are co-occuring which seems quite strange to me. The thermostat has gone bad, causing my check engine light to come on while driving (and having to have it towed). The car is also not recognize my remote key to operate the car. I am also getting "steering assist reduced" notifications while driving. I had the battery replaced 3 weeks ago because that was felt to be the cause of the steering assist notice, but after 1 week the notices started occurring again. I will also occasionally get "ECM" notices while driving. I don't see how all of this could be happening at the same time and it not be indicative of a more major Powertrain issue. I do not feel safe driving the car, even when these separate issues are repaired because I am fearful of the core, underlying cause.

Value stem gasket covers need replacing oil spilling out everywhere it’s a 2020 should not be happening Oil leak Hot and cold temperature not working properly A warning flashing for the power steering being deceased and not use That car get moved every hour just about always in jt working or just taking a break The auto shut of makes transmission slip or sounds like it is

The contact owns a 2020 Chevrolet Blazer. The contact stated while driving approximately 30 mph, there was an abnormal noise coming from the vehicle. In addition, the check engine warning light was illuminated, and the vehicle failed to operate. The vehicle was towed to the dealer but was not yet diagnosed. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 15,000.

Mileage: 15,000

IN 2 OCCASIONS MY VEHICLE CAME TO A COMPLETE STOP AND TURNED OFF ON ME. I WAS THINKING IT WAS A SAFETY FEATURE BUT AFTER THE 2ND TIME I WAS CONCERNED. TOOK IT TO DEALERSHIP AND THEY FOUND NOTHING WRONG WITH IT. ON ANOTHER OCCASION I WAS LEAVING MY HOUSE WHEN MY STEERING WHEEL GOT SUPER HARD AND MADE IT VERY DIFFICULT FOR ME TO TURN THE WHEEL. TOOK IT TO DEALERSHIP AND THEY FOUND NOTHING WRONG, ACCORDING TO THEM TRUCK WAS PERFECTLY FINE.

Mileage: 6,000

TL* THE CONTACT OWNS A 2020 CHEVROLET BLAZER. THE CONTACT STATED WHILE DRIVING 20 MPH, THE VEHICLE STARTED OVERHEATING. THE CONTACT THEN DROVE THE VEHICLE TO THE SIDE OF THE ROAD AND NOTICED THAT THE VEHICLE WAS LEAKING OIL. THE VEHICLE WAS THEN TOWED TO AN UNKNOWN DEALER. THE CONTACT STATED THAT SEVERAL UNKNOWN WARNING LIGHTS WERE ILLUMINATED. THE VEHICLE WAS TAKEN TO CHEVROLET OF COLUMBUS (2825 MERCHANT MILE, COLUMBUS, IN 47201) WHERE IT WAS DIAGNOSED WITH RODENT DAMAGE TO THE WIRING HARNESS. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER HAD BEEN INFORMED OF THE FAILURE AND INFORMED THE CONTACT THAT THE EXPENSES WOULD NOT BE COVERED EVEN THOUGH THE VEHICLE WAS UNDER WARRANTY. THE FAILURE MILEAGE WAS APPROXIMATELY 300.

Mileage: 300