2020 GMC Acadia Complaints

STEERING — Filed 10/04/2026

Thermostat housing failed. Got the message of "Steering Assist Is Reduced – Drive With Care". Have seen this numerous times in message boards. Has been reproduced. Safety is put at risk with the steering assist reduced. Mine happened on an highway.

STEERING,ENGINE — Filed 09/24/2026

Engine thermostat not functioning properly, therefore the display stayed on cold and would not show temp. It also cause the fan to run fast to cool engine. The AC would not cool and reduce power steering assist error message comes on. This is a known problem by GM and there is a recall for this issue on many of these vehicles, other GMC and Cadillac vehicles. Our vehicle should be added to the recall list!

ENGINE — Filed 01/01/2025

Engine thermostat not functioning properly, opening too early and not allowing engine to operate at proper engine temperature. Check engine light comes on, reduce power steering assist error message comes on, engine temperature gauge reads cold when vehicle has been running for an extended period of time. This is a known problem by GM and there is a recall for this issue on many of these vehicles, other GMC and Cadillac vehicles. Our vehicle should be added to the recall list.

POWER TRAIN,ENGINE — Filed 09/21/2026

2020 GMC Acadia bucks/hesitates when I take off or slow down and speed back up. Mechanic looked at it can see engine is having random misfires. We have tried plugs, transmission fluid, looked at everything we could think of. The condition improves if I put into AWD but still exists and worsens for a period of time after it shifts back into FWD mode. My mechanic has done a lot of research and found that one possible issue was a stretched timing chain but since it is out of warranty I just couldn't afford to have them tear it down it is an enormous job to see if that was the issue. It also lines up with other known issues like the auto stop issues and possibly a fuel pump issue. I have seen many people complaining online about this particular issue but not many on here and no recalls on my vehicle regarding the known issues

BACK OVER PREVENTION — Filed 09/19/2025

The rear camera does not operate 100% of the time. This has happened multiple times over the year.

ELECTRICAL SYSTEM — Filed 09/18/2024

Receive error message about Power steering that shuts off AC and Temperature gauges. Happens constantly when vehicle is driven on freeway. Requires the battery to be disconnected and it resets until the next time.

SERVICE BRAKES — Filed 09/07/2026

While driving my 2020 GMC Acadia SLT AWD Turbo with my young daughters in the vehicle, the brake pedal suddenly and sporadically lost all hydraulic pressure and sank nearly all the way to the floorboard. The vehicle would only gradually roll to a slow stop. Simultaneously, the dashboard illuminated with ABS and Service ESC notifications. After turning the vehicle completely off and restarting it, the braking system temporarily reverted to normal function before randomly failing again on a subsequent drive. The vehicle was brought to a local brake shop where it was dangerously misdiagnosed, and it is currently at a GMC dealership for an emergency teardown. Previously, without any warning, the vehicle would also experience a brake failure upon backing out of my garage. Once the brake was immediately pressed again, it would work. This intermittent loss of total stopping power constitutes a severe, life-threatening manufacturing defect.

ENGINE — Filed 08/21/2026

Engine coolant thermostat failed open. Resulting in reduced steering capabilities, and no AC.

STEERING,UNKNOWN OR OTHER,ENGINE — Filed 08/13/2026

Received a power steering reduced notice when starting the car, noticed shortly after driving the temperature gauge had not moved from its resting position. A few trips later it still had not moved and the check engine light came on. Mechanic looked at it said it may be a sensor quoted $1k to fix. A few days later it randomly started working and the light went off so I did not have it fixed. About 4 months later the same code displayed on the dash with the same issues. This time I noticed the ac would not work either it only blew out hot air. Also the fan under the hood turns on as soon as the car is started. Been about 3 days and it started working again out of nowhere.

STEERING,ELECTRICAL SYSTEM,ENGINE — Filed 04/09/2026

[Symptom & Safety Hazard] While driving my 2020 GMC Acadia 3.6L V6, the Driver Information Center displayed the warning: "Steering Assist Reduced, Drive With Care" (SARDWC). Steering effort increased abruptly, the engine temperature gauge dropped to cold/zero, and the HVAC system lost air-conditioning function. The warning and reduction in steering assist presented a safety hazard and increased the risk of a crash. [Diagnostic Findings] Vehicle diagnostics identified DTC P0128 - Engine Coolant Temperature Below Thermostat Regulating Temperature. A GMC Certified Dealer technician diagnosed a failed engine coolant thermostat housing assembly. [Manufacturer Information] GM documentation links DTC P0128 and invalid engine coolant temperature signals to the "SARDWC" condition. GM Bulletin 17-NA-158 states the “SARDWC” condition is caused by an invalid coolant temperature signal and the steering module relies on coolant temperature information for steering-assist compensation. GM bulletin PIT5967 directs technicians to diagnose and repair DTC P0128 when the warning message is present. In Oct 2025, GM issued N252508350 for 2021 Acadia vehicles equipped with the 3.6L LGX engine due to an engine coolant thermostat condition. My 2020 Acadia is part of the same generation vehicle platform and is equipped with the same 3.6L LGX engine. It experienced the same thermostat-related failure symptoms, including DTC P0128 and the "SARDWC” warning. [Reason for Complaint] I am filing this complaint because a thermostat-related cooling-system failure resulted in a steering-assist warning and reduction in steering assist while the vehicle was being driven. Moreover, GM issued N252508350 for 2021 Acadia vehicles equipped with the 3.6L LGX engine due to the same engine coolant thermostat condition, yet similarly affected 2020 Acadia vehicles are not included. NHTSA should investigate whether additional 2020 vehicles are experiencing the same failure sequence and resulting safety risk.

STEERING — Filed 02/01/2026

"Steering Assist Is Reduced – Drive With Care" warning appeared while the vehicle is in motion. This may require increased steering effort and could affect a driver's ability to respond to changing traffic conditions. Any steering-related warning that appears unexpectedly while driving deserves serious attention. P0128 code was shown. The cause was a faulty thermostat housing assembly and needed to be repaired. This is an extremely common issue in this vehicle across many years and needs to be investigated.

STEERING — Filed 04/22/2026

Steering assist reduced is the warning. The AC will no longer work and the fan runs constantly. From what I’ve read, it is a popular problem for Acadia owners and the thermostat and sensor has to be replaced. We have not been able to replace ours yet because of the cost.

POWER TRAIN,UNKNOWN OR OTHER,FUEL/PROPULSION SYSTEM — Filed 03/01/2026

I believe my car should be included in this recall. I've had the dealer check and they say it's nothing wrong with my car. 2020 GMC Acadia Fuel Pump Recall GMC has announced that 2781 vehicles have been affected by a Fuel Pump recall. General Motors LLC (GM) is recalling certain 2020 Buick Enclave, Cadillac XT5, Cadillac XT6, Chevrolet Traverse, and GMC Acadia vehicles. The fuel pump's jet nozzle may have a plastic burr remaining from the manufacturing process, possibly causing a blocked nozzle and an insufficient fuel supply to the engine. Insufficient fuel supply can result in an engine stall without warning, increasing the risk of a crash. 2020 GMC Acadia Recall Fuel Pump GM will notify owners, and dealers will replace the fuel pump module. The recall began November 16, 2020. Owners may contact GMC customer service at 1-888-988-7267, Buick Customer service at 1-866-608-8080, Chevrolet customer service at 1-800-222-1020 or Cadillac customer service at 1-800-458-8006. GM's number for this recall is N202314760.

POWER TRAIN,ENGINE — Filed 06/22/2026

Thermostat and cooling sensor went out on my car. GMC issued a special coverage bulletin for 2021 Acadia since it's a widespread issue but not the 2020 (mine) which is also a widespread issue looking online. The repair is over $1000 and should be covered!

ELECTRICAL SYSTEM,ENGINE — Filed 04/01/2026

Thermostat issue causing check engine light as well as steering assist to be turned off. Fan constantly runs. Reset code and immediately is fine again for anywhere from a day to weeks but then happens again. Car is just out of warranty but seems to be common occurrence as there is a service bulletin for the 2021 model

ELECTRICAL SYSTEM,EXTERIOR LIGHTING,FORWARD COLLISION AVOIDANCE — Filed 05/01/2026

Back up camera randomly stops working (black screen-completely gone, or blue screen). Dash will randomly dim on its own and does not go back to normal unless car is shut off and turned back on. adaptive cruise control will disengage for no apparent reason. stabilitrak will flash on screen but no other indicators or reasons; nothing happens with car. Occasionally the blind spot mirror lights will not light up when vehicle is present.

ENGINE — Filed 04/15/2026

Coolant temperature sensor failed - it is still in the engine. the fan stays on high all the time. And the AC does not want to turn on. The car is extremely hot to drive in during the summer months. I have to transport persons who are seniors and in their mid 80s. It is not safe to drive this car in the summer. I can't tell if its over heating or what is happening. The coolant temperature gauge does not work. The dealer said my car is out of warranty and that the AC will not start until the sensor is replaced. I said that it has less than 50,000 miles. They will not help me. The vehicle has not been inspected anyone other than the service mechanic. The engine light start coming on about a month ago. I drove first to an autoparts store to see if they could help. this is the first time I learned that it could be a bad sensor.

ENGINE — Filed 05/15/2025

A common issue in GMC vehicles (particularly 2017–2020 Acadias) is a "Steering Assist Reduced" warning message triggered by a failed engine coolant thermostat that gets stuck open. This causes the engine to run too cold (P0128 code), causing the computer to reduce steering assist (which is dangerous) and run fans on high, also the air conditioner fails. I have seen many complaints about this and it seems to be a manufacturers problem. GMC put out a repair bulletin for the 2021 models with this issue. It's time to address these other years.

ELECTRICAL SYSTEM — Filed 10/01/2025

My backup camera does not work when engaged in reverse, causes the radio to turn off and on.

STEERING,FUEL SYSTEM, GASOLINE,ENGINE — Filed 04/14/2026

The contact owns a 2020 GMC Acadia. The contact stated that while driving the vehicle, it stalled after initially adding fuel. Even though the reading indicated there was 1/8 of a tank of fuel. The fuel gauge failed to move. The thermostat was stuck open. The electric steering was not working properly. The engine light was illuminated. The traction control was turned off. The contact stated that the failure was related to NHTSA Campaign Number: 20V639000 (Fuel System, Gasoline). The contact stated that he was a master mechanic. The contact called the local dealer, but the vehicle was not diagnosed or repaired. The contact called two other local dealers, Tadd Jenkins Chevy 409 Farnsworth Way, Rigby, ID 83442, and Smith Chevrolet. Address: 3477 Pioneer Dr Suite 200, Idaho Falls, ID 83402. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 61,699.

ELECTRICAL SYSTEM — Filed 02/20/2026

My infotainment screen just has lines on it. I am the second owner of this vehicle. It just stopped working on day and has not come back. I cannot use my back up camera system now either. I have read where this has been an issue with the 2020 model and a possible crimping in the wiring system. I am wondering if this is the issue here. The car has been in no accidents under my ownership.

ELECTRICAL SYSTEM,FORWARD COLLISION AVOIDANCE — Filed 04/16/2023

I bought my car [XXX] it had 7 miles. I loved my car. Then in January 2021 things just went crazy. It started with park light on. My forward brake assist warning didn’t work, my back up camera in and out . My braking and stability were on and off. Then weird codes like. Engine at half power, unable to shift soon and speed control out. Then if I hit a bump message went away and speed control back on. I’ve taken care into another GMC dealer because dealer I bought my car at , closed up and took off!! Took it to closet dealer. Not long after repairs same issues started! So many different problems all at once! I have been treated horribly during these issues by dealership and extended warranty company. Dealer had my car for 3 weeks ! They couldn’t figure out the problem. I sat there for 4 hrs sent me home told to come back for 9 mile test! Why in 4 hrs that wasn’t done. So again the unable to shift message back on! I get in my car it starts but won’t shift ! Dealer charged me 250 to tow to shop! When they said I’d be fine ! I had more issues again and again! I’ve been driving over 40 yrs no accidents. I bumped into someone during a huge traffic jam in Ohio! Braking didn’t work no warning even . I should speak to a lawyer and could explain more to a person on filing these complaints. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

STRUCTURE,VISIBILITY/WIPER — Filed 12/20/2022

Rear view camera stopped working as I was backing up and ran into a pole damaged my right rear wheel well and panel.

AIR BAGS,SEATS — Filed 08/07/2021

The contact owns a 2020 GMC Acadia. The contact stated that she was rear-ended by another vehicle at a high rate of speed while attempting to make a left turn. As a result, the front passenger seat fractured. The air bags failed to deploy upon impact; the contact hit her head and was knocked unconscious during the incident. The contact was taken to the hospital by ambulance and was treated for a hematoma on her forehead above her right eye. Her husband, who was driving the vehicle, was later treated for muscle pain in his back. A police report was filed at the scene. The vehicle was towed from the scene to an independent mechanic where it remained in their possession. The dealer nor the manufacturer had to be notified of the failure. The contact stated that the vehicle sustained significant damage; however, it had yet to be examined or deemed a loss. The vehicle had yet to be repaired. The failure mileage was approximately 10,000.

AIR BAGS,STRUCTURE,VEHICLE SPEED CONTROL — Filed 06/01/2021

The ACADIA 2020 while in slow motion approaching my private condominium parking spot, accelerated autonomously and then slammed into the cement wall. Airbags deployed, no warning of collision, seriously damaged both car and cement wall. No bodily injuries. I researched the possible cause coded P2138 which involves the drive by wire sensors which connect the throttle pedal and the CPU that controls the mechanical throttle gas system. That might be the cause of the autonomous acceleration like explained about the P2138 sensors issues.