2018 GMC Acadia engine problems

Filed Nov 2, 2026 · Electrical, Engine · WV

Our vehicle’s horn beeped and a message on the dash said vehicle not in park. I copied the following from your web site and am requesting an update: General Motors has acknowledged the "Shift to Park" issue through several Technical Service Bulletins (TSBs). While there hasn't been a formal safety recall for this specific shifter issue as of early 2026, a class-action lawsuit has been filed alleging one is needed.

Filed Oct 25, 2026 · Engine · CT

Steering assist warning comes on when I start the car and then the engine fan starts up very loudly and code PO128. My car has 48,000 miles and is a 2018. I am seeing this is a known issue and should be part of a recall so I want to know if it’s covered.

Filed Sep 29, 2026 · Electrical, Engine · PA

I get error electric Steering assist reduced or unavailable drive with care at around 84234 miles on my car . Upon looking up problem on Internet it has to do with the Thermostat. I also found where Gm has a bulletin N252508350 which only seems to cover certain vehicles with the same problem. This seems to happen at all different miles driven on vehicles. I don't see how Gm can get away with only fixing certain vehicles with this safety problem when it shuts down the electric steering assist . This problem from what I can find on the internet is common to all years from 2017 up in Acadia with the 3.6L engine . The Thermostats seem to be defective and I feel Gm needs to address this problem for all of these vehicles . Not just for there special bulletin N252508350 which covers some vehicles in 2021with 3.6L engines. If the engine design was like the old engines and easy to replace the Thermostat by just taking out 2 bolts , I would say no problem I will replace it .But when you have to take half the Engine apart just to replace a 20.00 part that is defective that affects the steering of the vehicle, they need to have a safety recall.

Filed Sep 11, 2026 · Engine · VA

The car will frequently but not always fail to shut off when the start/stop button is pushed while in Park. The message "shift to park" come up on the display and a yellow light comes on in the button. I have to restart the engine and it often takes as many as 10 attempts to finally shut off the engine. Between each attempt I have to shift the transmission out of park and back into park. This has been happening for more than a month.

Filed Jul 2, 2026 · Engine, Transmission · CT

Hesitants and Shudders when shifting into 2nd gear.

Filed May 20, 2026 · Engine, Steering · TX

I am getting the known P0128 code. My engine says it's cold when it's not, my AC isn't working, and I am getting a message that says "Steer assist reduced. Drive with care". This is a known problem and complaint of the GMC Acadia.

Filed Feb 7, 2026 · Brakes, Electrical · TX · crash

The vehicle has experienced repeated electrical and engine-related malfunctions, including random engine shutdowns while driving and random no-start conditions. The thermostat and cooling system failed and were replaced in 2024. Multiple sensors have failed. The braking system remains noisy even after brake replacement. The lane detection safety system does not provide audible alerts. The vehicle is currently operational and available for inspection upon request. How was your safety or the safety of others put at risk? The vehicle has randomly shut off while driving on both highways and city roads in Azle, Texas. This occurred while my two children were in the vehicle. When the engine shut off, there was a risk of losing power steering and braking assist, which could have caused an accident, especially at highway speeds and in traffic. Has the problem been reproduced or confirmed by a dealer or independent service center? The thermostat and cooling system failure were confirmed and repaired by a service center in 2024. Electrical and sensor issues have occurred repeatedly but have not been fully diagnosed or resolved. Brake noise persists despite replacement. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? UNKNOWN. The vehicle has been serviced by repair facilities, but the manufacturer has not provided a definitive diagnosis for the engine shutdown and electrical failures. Were there any warning lamps, messages, or other symptoms prior to the failure? When did they first appear? Yes. Various warning lights and symptoms appeared prior to failures, including cooling system warnings and sensor alerts. Electrical issues and battery failures have occurred repeatedly, with batteries lasting only 2–3 years. Symptoms began after purchase and have continued throughout ownership. Additional details The brakes have been noisy even after replacement, and the lane detection system does not produce audible warni

Filed Dec 20, 2025 · Engine, Steering · MN

The warning light for a steering assist needs service came on the dash. The dealer had a code (po128) that pertained to a bad thermostat and coolant temp. sensor. The steering assist could have failed, along with possible engine damage. The dealer replaced the thermostat and the coolant temp sensor. Their were no police or insurance reports needed.

Filed Oct 23, 2025 · Engine, Fuel system · 126,000 miles · MI

The contact owns a 2018 GMC Acadia. The contact stated that while driving at an undisclosed speed, the vehicle failed to accelerate while attempting to shift gears. The contact stated that the vehicle jerked and made an abnormal sound, with the check engine warning light illuminated. Additionally, the contact stated there was black and white smoke coming from the rear of the vehicle. The vehicle was taken to the dealer, where it was diagnosed with transmission, cooling system, and fuel system failures. The dealer also determined that the engine was leaking oil. The dealer informed the contact that the vehicle required several repairs. The vehicle was not yet repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 126,000.

Filed May 5, 2025 · Brakes, Engine · PA

I have a 2018 GMC Acadia that is now displaying " shift to park " while the vehicle is in park. Upon extensive research I see GMC did issue a recall however, my particular VIN was not included. Its NOW displaying the error message which would lead me to believe it IS part of the recall. I called my local GMC dealership (Langhorne, PA.) and they said this was not covered since my VIN was not issues a recall.