2021 GMC Acadia: check engine light

Filed Oct 29, 2026 · Electrical · VT

Vehicle stalled several times. Check engine light and many code came up. Crack sensors replaced. Veh still stalls. Dealer and independent dealer believes it might be cpu. All wires from cpu checked with no issue found. When veh stalls if you manipulate the wire veh will start and run with demished power and demished steering control. Rpm go to off mode. Has happened on highway and side road. Very scary with 3 kids in car on highway.... not able to resolve issue. Veh has a little less then 60k

Filed Oct 15, 2026 · Fuel system · OH

exhaust flex pipe is cracked. Causes fumes of gas to be released through the crack. inspected by GMC Repair shop Vibrating noise started, then a few days later the smell of gas, and now yes the Engine light is on. This has been on going for about 3 weeks.

Filed May 6, 2026 · Engine · OK

Bought the acadia in june of 2021, in december of 2022 had to have the radiator replaced due to it leaking. This was found on routine maintenance and was not having any issues whatsoever. I received no alerts on my dash such as a check engine light. Fast Forward to March 2026, I received a message of "steering assist reduced. drive with care." The engine seemed like it was still running despite the car being off. This was happening intermittently and definitely not every time I drove. I made an appointment for the regular oil change and to have this message investigated. Initially they told me it was the temperature regulator, however, they put a new regulator on and tried to re-pressurize the system. The system failed to re-pressurize due to the radiator leaking AGAIN. Of course, there was a 2 year warranty on the radiator after it was replaced initially and now we are about a 1.5 years outside the warranty.

Filed Mar 20, 2026 · Engine · 69,000 miles · NJ

The contact owns a 2021 GMC Acadia. The contact stated that while driving at an undisclosed speed, the check engine warning light illuminated. In addition, the coolant fan was running after the engine was turned off. The vehicle was taken to Auto Zone to be diagnosed due to the check engine warning light being illuminated. The contact was informed that DTC: P1098; was retrieved, which indicated a fault with the coolant control valve. The vehicle was taken to the dealer, where it was confirmed that the coolant control valve had failed. The vehicle remained at the dealer unrepaired. The contact related the failure to the Manufacturer Recall Number: N252508341. However, the VIN was not included in the recall. The manufacturer was made aware of the failure and advised that the VIN was not under recall. The failure mileage was approximately 69,000.

Filed Mar 4, 2026 · Electrical, Engine · OH

Car has had multiple issues with check engine light coming on for the last 2 years and stays on especially during the winter months. The purge pump has failed multiple times. The cooling fan has run after engine shutting off for multiple years now. The thermostat has been failing for the last 6 months. Now yesterday low power protection suddenly turned on driving on the expressway limiting power in the middle of traffic. Was able to get off at exit without accident and get car home. I guess we have to pay out of pocket to get fixed. This is a known issue that GM fails to include every VIN with the 2021 year or certain models and VINS.

Filed Feb 9, 2026 · Engine · 37,000 miles · MO

The contact owns a 2021 GMC Acadia. The contact stated while driving at an undisclosed speed, the check engine warning light illuminated and DTC: P04FB; was displayed. The vehicle was taken to the dealer where it was diagnosed with moisture of the crank case. The vehicle was repaired. The contact stated that the failure was a quick fix and was covered under the warranty. The contact stated that the failure had occurred several times and was covered under warranty. The contact was informed that there was no fix for the failure. The manufacturer was not made aware of the failure. The failure mileage was approximately 37,000.

Filed Jan 21, 2026 · Fuel system · 78,200 miles · MD

The contact owns a 2021 GMC Acadia. The contact stated that while the vehicle was parked, the vehicle started, and the contact exited the vehicle and ran into the house for a while. The contact stated that while reentering the vehicle, the contact noticed that the check engine warning light was illuminated. The contact was employed by an independent mechanic, and the vehicle was driven to the place of employment. The independent mechanic attached the mobile diagnostic tester to the vehicle and retrieved DTC: P023F, which indicated fuel pump secondary circuit failure. The contact was advised that the fuel pump module needed to be replaced. The vehicle was not repaired. The vehicle was not repaired. The contact referenced the federal safety agency Campaign Number: 21V422000 (Fuel System, Gasoline); however, the VIN was not associated. The manufacturer was made aware of the failure but provided no assistance. The contact was advised to contact the federal safety agency Hotline to report the failure. The failure mileage was approximately 78,200.

Filed Jan 8, 2026 · Driver assistance, Transmission · FL

Cars is not keeping track of temperature showing engine is cold after 30 minutes of driving, fan runs for extended periods of time after shutting off, check engine light comes on, steering assist alert comes in screen. All of this happens in a cycle. To stop it the battery has to be unplugged and reconnected resetting the car and everything goes back to being fine for a short period of time.

Filed Nov 19, 2025 · Engine, Fuel system · 36,970 miles · RI

The contact owns a 2021 GMC Acadia. The contact stated that while his wife was driving at an undisclosed speed, the vehicle inadvertently lost motive power. The driver was able to coast to the shoulder of the roadway, where the vehicle failed to restart. The check engine warning light was illuminated. The vehicle was towed to an independent mechanic, who diagnosed a failure with the fuel pump control module. The vehicle was repaired. The manufacturer was notified of the failure but provided no assistance. The failure mileage was 36,970.

Filed Nov 7, 2025 · Fuel system · 35,500 miles · VA

The contact owns a 2021 GMC Acadia. The contact stated while driving 75 MPH, the check engine warning light illuminated. Additionally, the accelerator pedal was depressed, but the vehicle failed to accelerate as intended. The vehicle was driven to the shoulder of the road. The contact stated while attempting to start the vehicle, the vehicle failed to start as intended. The contact stated that the failure had nearly caused the vehicle to be run over by a tractor trailer. The contact's wife and three minor children were also occupying the vehicle during the failure. The contact stated that he and his family could have been killed due to the failure. The vehicle was towed to the dealer, where it was diagnosed with fuel pump power control module failure. The contact was informed that the fuel pump power control module needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and a case was filed. The contact related the failure to an unknown recall; however, the VIN was not included in the recall. The failure mileage was approximately 35,500.

Filed Oct 22, 2025 · Electrical, Steering · MT

While driving, error popped up stating steering assist is reduced; drive with caution. Heat was no longer working. Engine temp was reading cold even though vehicle had been running for half hour and temp outside was 65 F. After vehicle was stopped, engine fan ran very loudly for at least 15 minutes. Took vehicle in to have diagnostics ran, and received error P0128 pointing to faulty engine coolant thermostat and sensor. Also received U0401 indicating insufficient data coming from ECM/PCM. I was told that together with U0401 and P0128 together indicate a communication problem between control modules. Check engine light was never on.

Filed Oct 8, 2025 · Transmission · TX

*Transmission or torque converter. *Vehicle shuddering or shaking at low speeds or when shifting. *Studders while trying to drive fromstop. Can casue accident. *No check engine lights or any warnings prior to failure. *Did not accuse anything when checked by diagnostice tool. *Issue started in Sept but is ongoing