2018 GMC Acadia engine problems

“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.”

“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.”

“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.”

“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.”

“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.…”

“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.”