2020 CHEVROLET BLAZER Electrical System Problems

Engine showing PO128 code. Steering Assist System reduced power. Engine fan constantly running. Engine temp on dash is stuck on the "C" mark, doesn't move. Thermostat and temp sensor replaced, issue continues. THIS IS A VERY COMMON PROBLEM ON GM VEHICLES WITH THE 3.6L AROUND THE 60,000 MILE MARK. GM NEEDS TO GET IT FIGURED OUT.

I received a check engine light which i took to Bell tire for diagnosis. Here is there diagnosis Comments: The P01F0 code on a 2020 Chevy Blazer means the engine coolant temperature is below the normal operating range, often due to a stuck-open thermostat (or both thermostats in models with dual units), a faulty Engine Coolant Temperature (ECT) sensor, or low coolant, leading to poor fuel economy and potential wear; fixing it usually involves replacing the thermostat(s) or sensor after checking coolant levels and wiring. After that i took the vehicle to GM Dealership. Even though this is a know issue with many vehicles from same year, i was told that my VIN is not part of recall and dealership ended up charging me 600+ to fix the issue. I am reaching out to seek help as i had exact same problem but GM is not covering the repairs because...

The driver information center suddenly indicated steering assist disabled, temperature gauge drops to below cold, air conditioning blows warm air. This issue has happened several times and is able to be reset by disconnecting/reconnecting the battery or using a scan tool. Temperature sensor is not the cause in my opinion, and I have read that the harness for the temperature sensor also includes the coil wires, which can lead to electrical/rf interference, triggering this issue. I have read about many owners having this same issue, even after temperature sensor and thermostat replacement, at low mileages. This should be recalled and handled by GM, whatever the cause.

Action required steering assist reduced and coolant temperature at 0. Air con blowing hot and check engine light on. The vehicle became hard to handle and keep in my lane on the interstate at high speeds. The problem has persisted. It has not been recitfied. I am not driving the car to avoid damage and danger. I bought the blazer on 1/6/26. The lights and issues began 8 days later. Dealership will not help me. 2020 Blazer RS AWD bought from Morgan city Toyota Louisiana

Very bad clunnk on driver side when hitting any bump on the road and it's loud.dealer ship sold me the car like that . Electrical issue gauge cluster radio cluster turn signals your first camera anything that works off the instrument cluster of the radio TV screen goes off while I'm driving comes back on hit a bump it comes back on no headlights driving at night time. The dealership sold me the car like this.

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

There seems to be a constant problem with the service driver assist error code popping up and check engine light coming on. The ac heating keeps losing temperature. I've looked for support for this issue and it seems to be a common problem for chevy owners. Why isn't there a recall on this.

Thermostat gauge isnt moving along side a message saying "Steering assis is reduced drive with care"

I got into my vehicle and it said “steering assist reduced. Drive with care”. the A/C stops working and refuses to cool as well as the cooled seats. The thermostat for the coolant reads “C” despite driving it 40+ miles in 83 degree weather. Tried disconnecting battery upon research and finding out many other people are having the same problem. The light turned off and came right back on the following morning

Shift to park issue. Vehicle shifts into park but does not register as such. Therefore, the vehicle keeps running and will not turn off or allow you to exist the vehicle. This is already a know issue with certain GM vehicles as is evident by a recall and Service Bulletins. However, none of those include the 2020 Chevy Blazer.

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.

Component/System Involved: The electric power steering system in my 2020 Chevy Blazer is malfunctioning. A warning appears on the dashboard: “Steering Assist is Reduced – Drive with Care.” When this happens, steering becomes very stiff and difficult. The issue is ongoing, and the component is available for inspection if requested. Safety Risk: This creates a serious safety hazard. The sudden loss of steering assist makes it hard to turn the wheel, especially at low speeds or when maneuvering. It puts me and others at risk, especially if it happens in traffic or while turning. Problem Confirmed by Dealer: No, the issue has not yet been inspected or confirmed by a dealer or service center. Inspection History: The vehicle has not been inspected by a dealership, manufacturer, police, or insurance. Warning Signs: The only warning is the “Steering Assist is Reduced – Drive with Care” message, which appears randomly—sometimes at startup,...

When I try to park the car, it says shift to park. Sometimes I can’t get the car to go into park to exit the vehicle or other times. I’ve shut the door and it has stayed on with the accessories because it won’t shut off

Shift to park message on display when car is already in park, preventing the car from turning off completely draining the battery completely.

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.

Vehicle thermostat would read cold while operating and the AC was not working. A message would populate in the dash stating "steering assist is reduced drive with care." Multiple forums stated it was a thermostat issue or temperature sensor. Also attempted to disconnect the battery for several minutes which would in turn clear the message and all would be working fine. This has been done multiple times and is at random when the message and AC stop working

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.

After the vehicle has been put into parked and attempted to shut off, a message displays “Action Required Shift To Park”. Although the vehicle is in parked there is some kind of sensor that is not reading it is in park. Vehicle first started doing this when parked on an incline but frequently happens since the first occurrence. One temporary solution is to shift into different gear or shake the gear 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.

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.

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...

SHIFT TO Park WARNING COMES ON WHEN CAR IS IN PARK, car electrical will not shut off until the shifter is shaken or car is turned back on and shifted into gear and back to park, may take several times

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....

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...

Shift to park message began appearing even after the shifter knob was in park. I cannot turn the vehicle off and it rolled backwards due to the vehicle not recognizing it was in park. This has now cost $700 to repair when its been a known issue with these vehicles for over 6 years and yet they refuse to issue a recall. This is dangerous and disgusting practice for a vehicle manufacturer to avoid keeping their customers safe.

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.

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.

when you put your Blazer in Park you get the warning light and chime to 'shift it into park'. So far it has happened to me 5 or 6 times in the past couple days. I can jiggle the shifter handle to get the chime to stop but it has me concerned. I have seen numerous posts about this same problem.

I started receiving the message “steering assist reduced, drive with care” although I’ve noticed no reduction in power steering. This has happened multiple times. The A/C stops working, the Temperature Gauge moves to 0 degrees and the engine fan goes to maximum speed. I have noted that this is a common issue with the Blazer.

Almost every time I start the car up it asks me if the vehicle is a Demo. I will sign in as a user and identify the vehicle and keys, but it seems to lose some of the information when it is turned off. It has happened hundreds of times.

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...

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...

Thermostat failure. No a/c, no power steering, engine light on.

Coolant temperature would not read, steering assist malfunctioning, air conditioner intermittent. Wiring harness for sensors loomed together with coil pack wiring interrupting signals.

COMMON ISSUE, The steering assist is reduced and temp gauge is stuck on C. This either a thermostat or temp sensor issue.

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!!

When I parked and tried to turn off car it would continue to run. I had to put it in park and drive back to park several times before car would turn off. There’s a recall for this issue on other blazers and I feel 2020 blazers should be included. The dealer replaced the shifter assembly, cleared OTC

We have experienced 2 issues that are very well known issues, I will list them here. First, is the Shift to Park issue, that involves an electrical switch and wiring harness on the shifter assembly. Second, is regarding a "driver assist reduced drive with care" alert message that includes Diagnostic Trouble Code (DTC) P0128, but is actually related to either the engine cooling sensor or the cooling thermostat housing assembly. Both issues are very well known, and many owners have had these issues.

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.

Vehicle keeps throwing “steering assistance reduced please drive with care” message. It causes my car fan to constantly run. It also causes the coolant gauge to not work the needle drops below that cool like it’s not on and then the car won’t blow cold air from the vents. This message tells me that something could be wrong with the steering which puts my safety at risk. This issue has been happening to me on and off for months now and there are multiple complaints of multiple Chevy owners having the same problem this issue needs to be addressed.

Vehicle keeps throwing “steering assistance reduced please drive with care” message. It causes my car fan to constantly run. It also causes the coolant gauge to not work the needle drops below that cool like it’s not on and then the car won’t blow cold air from the vents. This message tells me that something could be wrong with the steering which puts my safety at risk. This issue has been happening to me on and off for months now and there are multiple complaints of multiple Chevy owners having the same problem this issue needs to be addressed.

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

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

We have a 2020 Blazer that will occasionally show "Shift to Park" error message and won't allow us to turn off the motor. Searching this issue, we see many people have the same problem and GM makes us pay to repair the problem.The dealer said the shift control module had to be replaced. It cost us almost $300.00 to repair. GM Service Bulletin No.: 19-NA-206 has been issued but no recall has been issued by NHTSA. There are also several lawsuits filed but we have been unable to see the results of those lawsuits. Please make GM pay and/or reimburse for these repairs. We live in Wiscons

The valve on the thermostat stuck open causing the vehicle to go into a default mode. Ramping the radiator to full high and the thermostat will not come off of C. It has caused an issue with the A/C not blowing cold and also causes a message to pop up upon starting the vehicle stating that steering assistance is reduced, drive with caution. Upon doing research, thousands of people have had this similar issue with different model chevys as well. And the part is on the back side of the engine so injectors and air intakes have to be removed to preform any work to a $100 part.

Transmission skips while driving, there’s some sort of glitch with the electrical that causes the steering assist to shut down and the fan to over work, like it would if it were over heating but the temp of normal.

Unknown car will not shift into park without me having to re-shift to park and then the vehicle will shut off after re-shifting.