Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2021 Chevrolet Trailblazer owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2021 Chevrolet Trailblazer. The contact stated that while the vehicle was parked, the vehicle was turned off however, the blower fan independently activated. No warning light was illuminated. The contact's husband had just parked the vehicle upon arriving at the place of employment. The contact's husband is a certified mechanic. The vehicle was diagnosed with coolant intrusion and a misfire in the engine. The contact was informed that the spark plugs needed to be replaced; however, the spark plugs had to be ordered. The vehicle was not repaired. The vehicle was driven to the residence. The contact's husband parked the vehicle and turned the vehicle off. The vehicle failed to start as intended and was towed to the dealer to be diagnosed and the dealer determined that there was a crack in the head gasket. …
The contact owns a 2021 Chevrolet Trailblazer. The contact stated that while driving at an undisclosed speed, the AUTO-STOP was not functioning properly. Additionally, the doors would not unlock on two separate occasions. Additionally, the keyless ignition button would not turn off the vehicle until the contact applied pressure while pressing on the button. The contact also stated that the tire pressure sensor was faulty. The check engine warning light and reduced power message was displayed on the instrument panel. The vehicle was taken to the dealer on two separate occasions and the dealer informed the contact that the AUTO-STOP function was unprogrammed due to the weather however, the dealer was unable to duplicate the failure. The dealer reprogrammed the AUTO-STOP software and tire pressure sensor however, the failure recurred. …
The contact owns a 2021 Chevrolet Trailblazer. The contact stated while driving at an undisclosed speed, the vehicle inadvertently lost motive power and was unable to accelerate above 40 MPH. The contact stated that after the failure, the vehicle went into LIMP Mode. The check engine warning light was illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the variable valve timing system. Additionally, the dealer found that the intake camshaft actuator was incorrectly positioned, resulting in damages to the exhaust camshaft. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling), but the VIN was not included. The manufacturer was notified of the failure but provided no assistance. The failure mileage was 81,000.
The contact owns a 2021 Chevrolet Trailblazer. The contact stated that after reversing, the transmission was shifted to drive (D), but the vehicle failed to immediately recognize the selected gear. The check engine warning later illuminated. The vehicle was taken to an independent mechanic, who determined that the under boost, transmission control module, and transmission control solenoid had failed, and there was a loss of communication with the radio and loss of communication with the telematic control module. The mechanic advised the contact to take the vehicle to the dealer for assistance. The vehicle was not repaired. The manufacturer was made aware of the failure and advised the contact to report the failure to the NHTSA Hotline. The failure mileage was approximately 42,000.
The contact owns a 2021 Chevrolet Trailblazer. The contact stated while driving at 5-10 MPH, there was an extremely loud clicking and rattling sound coming from the vehicle. The contact stated that there was an unknown object moving inside the vehicle. There were no warning lights illuminated. The vehicle was taken to the local dealer, where it was diagnosed that the turbo needed to be changed. The vehicle was repaired, but the failure recurred. The dealer informed the contact that the sound was duplicated in other similar vehicles and informed the contact that no further action was needed. The manufacturer was not contacted. The failure mileage was approximately 48,482.
vThe contact owns a 2021 Chevrolet Blazer. The contact stated that while driving at an undisclosed speed, there was an abnormal sound coming from the vehicle. No warning lights were illuminated. The vehicle was taken to the dealer, where it was diagnosed with a crack between the muffler and front pipe. The contact was informed that the muffler needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure but provided no assistance. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 57,850.
I have had the 2021 Chevy Trailblazer since May 2021, it has been 15 months, not even a year and a half off the lot and i have had wayyyy too many problems. I have has service the stabilitrak stability control system, service the antilock breaking system multiple times within the first 8-10 months. I had to get a part replaced due to that. The dealership had my vehicle literally for a month after i bought it, had an open tak report through Gm due to my engine light coming on. Gm did not know why it was happening. Had 2 service engine and transmission system alerts. I have had a fuel injector and line replaced as well within the first 6 months. I have had to get the system updated 2 times also. Now August 2022 im having service battery, or starter. Have had my vehicle shut off on me at an intersection then come back on two different times. …
Experiencing reduced speed, rattling noise, check engine light, power steering light on. Chevy app shows throttle control system and antilock break system error messages. Took to Chev dealership. Advised it was fuel injector (1 /4 was burned out). Had all 4 replaced ($3000). Picked up car on a Friday, vehicle was having the same issues next day Saturday. Took it back on Monday, it is now Wednesday and they're saying it's the turbo charger now (another $3000). Mechanic couldn't figure out what the issue was so it took 3 days for him to now say it's the turbo charger. I think it was the turbo charger from the get go! What's the purpose of the diagnostics ($250)? Isn't it to pinpointed the issue? 1st day, took him 4 hours to say it was the fuel injector. 2nd time around it took 3 days. I kept showing them and telling them it's the throttle control system! They're trying to rip me off! …
This vehicle was sold as new when this vehicle had a defective Turbo Underboost issue from a ECM Issue previously prior to the 2022 Trailblazer being sold to us. This vehicle has a shift to park issue which sticks when you try to Park the vehicle. Next This vehicle has had 4 prior incidents of attempted repair of this Turbo Underboost and a failure to pass emissions which lead to the engine and transmission failure of this vehicle. I have waited since July 6, 2025 of this vehicle being in the shop no rental no loaner. Now no replacement vehicle. For more than nine months and a General Motors open claim since 07/06/2025! …
2021 Chevrolet Trailblazer RS (123,000) - Coolant control Valve failure Cooling issues after 20-25 mins of driving. No Check engine lights initially just temperature gauge climbing. After 3 day of trying to drive to and from work. "Engine reduced" and P3075 code. Had it towed to dealership, in which they replaced the water pump. This DID NOT fix the issue. The next two drives (from work, and to work), I had to pull off the road several times to get the car cooled down, and run heater on full blast to drop temperature. Pulling off the road in heavy interstate traffic consistently because of the Coolant Control Valve (25207464 GM). Not to mention me, looking at the temp gauge most of the way to work, versus eyes on the road. The old thermostats would at least give you a temperature code, and not an Engine Coolant Flow Too Low error which leads to water pump being replaced erroneously. …
Engine complaints in other Trailblazer years
Frequently asked questions
How common are engine problems on the 2021 Chevrolet Trailblazer?
NHTSA has 39 complaints about the engine & cooling of the 2021 Chevrolet Trailblazer, 20% of the model year's 196 complaints. The component named most often is exhaust system › emission control (1 mentions).
Is there a recall for 2021 Chevrolet Trailblazer engine problems?
No. NHTSA lists no engine & cooling recall for the 2021 Chevrolet Trailblazer, though it has 4 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2021 Chevrolet Trailblazer engine problems start?
Half of the complaints with a recorded mileage happened before about 58,000 miles, and 17% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 1 fire and 0 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.