2019 GMC Acadia

* DTC PO128: Engine Coolant Temperature Below
Thermostat Regulating Temperature * "Steering Assist Is Reduced - Drive With Care" displayed while driving * AC not functioning properly * Engine temperature gauge pinned at "Cold" * Cooling fans continue to run after shutdown

NHTSA ID

11776559

Incident

Nov 6, 2026

When putting the vehicle in park to turn it off, the dash indicates that I need to put the vehicle in park. But it is in park and it will not let me shut off the vehicle.

NHTSA ID

11772881

Incident

Oct 1, 2026

My driver side front control arm, and stabilizer bar snapped on me while on the highway without warning causing me to crash. I'm blessed to be alive.

NHTSA ID

11769912

Incident

Sep 28, 2026

While attempting to turn vehicle off, the message shift to park was given. Could not shut vehicle off! Has happened multiple times in the past, then disappears for awhile. Comes back again at will. Have seen multiple complaints on this issue falling back to a defective micro-switch within the shifter assym. Former GM tech here---

NHTSA ID

11765518

Incident

Jul 23, 2026

I own a 2019 GMC Acadia equipped with the 3.6L V6 engine. VIN. See form above In 2025, the engine coolant thermostat failed on my vehicle and required replacement at my expense. I am submitting this complaint because I believe this may represent a recurring component problem affecting 2019 GMC Acadia vehicles and I would like NHTSA to determine whether the condition presents an unreasonable risk to motor vehicle safety. General Motors has published service information addressing thermostat-related conditions on GMC Acadia vehicles equipped with the 3.6L engine. GM has also issued special coverage for an engine coolant thermostat condition on certain GM vehicles. GM’s special coverage describes a thermostat that can open at a lower temperature than intended, resulting in a malfunction indicator/check-engine light and diagnostic trouble code, and in some cases causing the engine cooling fans to continue running after the vehicle is shut off. My 2019 Acadia uses the 3.6L engine and the thermostat assembly addressed in GM’s service information. Despite this, my 2019 model year is not included in the current extended thermostat coverage. There is also a second, independent occurrence involving the same model year. My father owns a separate 2019 GMC Acadia, and the thermostat on his vehicle also required replacement in 2026. These are two separate vehicles that experienced thermostat failures requiring replacement. I understand that a thermostat failure is not necessarily a safety defect by itself. However, I am concerned that a recurring failure of this component could potentially create a safety risk depending on the failure mode and resulting vehicle condition. I am therefore asking NHTSA to review the available consumer complaints, manufacturer service information, warranty data, and GM special-coverage actions to determine whether there is a safety-related defect affecting 2019 GMC Acadia vehicles equipped with the 3.6L engine.

NHTSA ID

11765267

Incident

Apr 12, 2025

The contact owns a 2019 GMC Acadia. The contact stated that the fuel gauge displayed an inaccurate fuel level. The fuel sending unit was replaced twice; however, the failure persisted. The contact became aware of the recurring failure while refueling the vehicle and noticing that the vehicle consumed more fuel than the fuel gauge indicated. The vehicle was taken to the dealer, where it was determined that the fuel sending unit needed to be disassembled for further diagnostic testing. The manufacturer was notified of the failure by phone. The failure mileage was 64,382.

NHTSA ID

11764429

Incident

Jul 1, 2025

Mileage

64,382 mi

I am submitting this complaint to request that NHTSA investigate a potential safety defect involving the engine coolant temperature monitoring system, thermostat/engine coolant temperature sensor system, and its relationship to reduced steering assist in 2019 GMC Acadia vehicles. My 2019 GMC Acadia, currently at approximately 91,500 miles, has experienced the following symptoms: • The engine temperature gauge remains flat or reads abnormally low/cold. • The cooling fans run continuously at extremely high speed, creating a loud "screaming" fan noise. • The vehicle displays the warning message "Steering Assist is Reduced — Drive with Care." • The vehicle has a history of diagnostic trouble code P0128, "Engine Coolant Temperature Below Thermostat Regulating Temperature." I am concerned that these symptoms are related and represent a potential safety defect rather than an isolated thermostat or cooling-system repair. GM has issued bulletin PIT5967, "Service Steering Message With P0128," which applies to GMC Acadia vehicles from model years 2017 through 2023. The bulletin states that when P0128 is present, the ECM may be reading coolant temperature incorrectly and that a "Service Steering Message" may be displayed to protect the steering gear in the event of an undetected overheating condition. GM instructs technicians to diagnose and repair P0128 first. GM bulletin 17-NA-158 also describes a relationship between P0128, an invalid coolant-temperature signal, and the "Steering Assist Reduced, Drive With Care" warning. The bulletin explains that the steering module relies on valid coolant-temperature information to provide additional steering assistance under cold conditions. Also will not register when put in park. Getting error message "shift to park" take multiple restarts of the vehicle and shifting gear back and forth for it to register.

NHTSA ID

11764000

Incident

Aug 1, 2026

Vehicle continued to have Shift to park message when car was already in park. This is a known issue in some other GMC vehicles. Safety issue that the battery could drain or the car could roll unexpectedly. This message repeatedly displayed on the vehicle. The dealer confirmed the problem and performed the repair. Repair order number is XXX for $549.17 on XXX at Boucher Buick GMC of Waukesha [XXX].While there isn't a recall on file for this specific VIN number, I believe it should be included in the recall and I am requesting reimbursement. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11762800

Incident

Aug 24, 2026

This Preliminary Information communication provides information to the technician about vehicles that have an intermittent no crank, no start, or start stall concern with the security light coming on. Technician may find Diagnostic Trouble Codes B3055, B3

This PI provides Diagnostics tips on how the LIN bus works and how to diagnosis it.

This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.

PI to help diagnose A/C concern

This preliminary information communicates information about how to determine if a wheel and tires size change is available.

This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.