2020 GMC Acadia Problems

What owners report

Owners of the 2020 GMC Acadia most often describe a thermostat-related cooling problem that brings a "Steering Assist Reduced" warning along with a temperature gauge that sits at cold, the cooling fan running high and the air conditioning quitting, often appearing without much warning in normal driving. Transmission shudder and hard shifting is the other recurring theme, with several owners told they needed a torque converter or transmission replacement. A separate cluster of complaints covers door locks and interior electronics that stop responding, and a smaller group describes the vehicle stalling or losing power.

1. 1
   Engine

   Thermostat sticks open: steering assist, A/C and gauges

   • 32 complaints (30%)
   • median 61,699 mi at 6.5 yrs old (3 state mileage, few)
   • owner-quoted repair $1,550 (median of 6 quotes)
   • filed 2022–2026

   Owners describe a sequence in which the temperature gauge drops to cold and stays there, the cooling fan runs at high speed, the air conditioning blows warm air, and a "Steering Assist Reduced - Drive With Care" message appears, sometimes with increased steering effort. Several say a thermostat-related code was stored and the fix was a thermostat or thermostat housing replacement, while others report that clearing the code restores normal behavior temporarily before it returns. Some owners note that a service bulletin covers this symptom on a later model year but not on their 2020 vehicle. Reported across a wide range of mileage, from vehicles still at low mileage to examples past 60,000 miles, and not tied to weather.

   What to check: On a test drive, watch whether the temperature gauge climbs to normal and check that the A/C blows cold; ask the seller whether a thermostat or thermostat housing has been replaced and whether a thermostat-related code has ever been stored.

   2 excerpts from owner complaints in NHTSA records

   “Failed component was thermostat and I do not have possession of it. Over several months, I would receive infrequent and unrepeatable messages of steering assist reduced and my temp gauge would drop all the way to the cold side. No other recorded codes were being set after frequent trips to Autozone for verification and there were no check engine light warnings. No other signs of vehicle malfunctioning were present either. …”

   NHTSA complaint #11717530, filed 2026-02

   “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. …”

   NHTSA complaint #11758890, filed 2026-08
2. 2
   Transmission and drivetrain

   Transmission shudder and hard or delayed shifting

   • 16 complaints (15%)
   • median 71,000 mi at 5.0 yrs old (4 state mileage, few)
   • filed 2022–2026

   Complaints describe a shudder or vibration while driving, often at steady speeds or light throttle, plus hard downshifts, hesitation when accelerating from a stop and occasional abnormal shifting behavior. Some owners say the dealer confirmed the concern and performed a transmission flush, others were told a torque converter needed replacement, and a few report the symptoms returned afterward. A few complaints mention transmission messages appearing on the driver information display. Mostly reported between roughly 15,000 and 80,000 miles, often beginning with a low-speed or steady-throttle shudder.

   Recall 20V6680002 related service bulletins

   What to check: Drive the vehicle at a steady 40-60 mph and at light acceleration to feel for shudder or vibration, and ask for service records showing whether a transmission flush, torque converter, or transmission work was done.

   2 excerpts from owner complaints in NHTSA records

   “I own a 2020 GMC Acadia that has experienced multiple major mechanical failures within one year. In January 2025, at around 74,000 miles, the transmission failed completely with no warning or clear indication of what was wrong. The vehicle suddenly lost power while driving, creating a safety risk for me and my child. I was quoted around $12,000 for the transmission replacement initially before getting GM involved. …”

   NHTSA complaint #11697288, filed 2025-11

   “The torque converter in the transmission has been vibrating for over a year now. I can imagine it is causing more damage to the rest of the transmission. Now I can feel the shifting starting to get rough, loss of power, and dark transmission fluid. I had the problem confirmed with an independent service center. There have been no warning lamps as of yet. But it's only a matter of time that I will need a torque converter replacement and/or full transmission replacement.”

   NHTSA complaint #11722466, filed 2026-03
3. 3
   Electrical system

   Door locks and interior electronics intermittently stop

   • 20 complaints (19%)
   • median 25,150 mi at 3.7 yrs old (4 state mileage, few)
   • 1 mention a crash, fire or injury
   • filed 2019–2026

   Owners report the power door locks failing to lock or unlock from the interior buttons or the key fob, in some cases leaving occupants unable to open the doors from inside, and several describe being locked out in rain or after a car wash. Others describe blank center displays, cameras and navigation dropping out, and the instrument cluster briefly showing all gauges at zero along with traction control and ABS messages. Dealers in these complaints often could not reproduce or resolve the concern, and in some cases replaced the radio or battery without lasting effect. Reported from as little as a few hundred miles up to around 68,000 miles, with some cases tied to wet weather.

   Recall 22V709000

   What to check: Check that all doors lock and unlock from both the fob and the interior buttons, operate the rear camera and center display, and ask whether any lock, radio, or battery repairs have been attempted.

   2 excerpts from owner complaints in NHTSA records

   “Two days after purchasing a new 2020 Gmc Acadia I get an error on the display sd card removed along with various other error messages. Dealer talks to Gmc tech line and they advise to replace radio. Radio was replaced and errors began same day I picked it up. Dealer is replacing radio again, but unsure if this will fix the issue. The vehicle does not work as intended as when you press the nav button various error messages pop up and navigation does not work.”

   NHTSA complaint #11282399, filed 2019-11, 100 miles

   “When it rains(or car wash) my power locks don't work. I get locked out of my car. My car reset itself in the middle of an intersection(like I turned it off and back on again). One of my gauges is always not working. The sunroof doesn't work right. Water is getting in the electrical area somehow. I've taken it to two chevrolet dealerships, but no help.”

   NHTSA complaint #11646575, filed 2025-03
4. 4
   Fuel system

   Stalling or loss of power while driving

   • 11 complaints (10%)
   • median 32,499 mi at 3.3 yrs old (4 state mileage, few)
   • filed 2020–2026

   Complaints describe the engine losing power or shutting off while driving, in some cases at an intersection, with difficulty restarting and occasional towing. A few owners connect the symptom to a low fuel reading or to the fuel pump recall, and one describes the gauge failing to move after refueling. Others describe a fuel level that dropped faster than expected with no warning before the engine quit. Reported from under 2,000 miles up to around 104,000 miles.

   Recall 20V639000

   What to check: Ask whether the fuel pump recall work was completed for this vehicle, and note on a test drive whether the fuel gauge responds promptly after refueling.

   2 excerpts from owner complaints in NHTSA records

   “Driving along no issues, car says 60 miles to empty no fuel warning light or anything, when car just suddenly loses power, was able to get to side of road. Told me to restart engine, and it wouldnt fire back up. Put a gallon of gas in and it fired back up. Owned car for almost 3 weeks cant believe there was no indication fuel was apparently that low. 60 miles to empty should have been able to finish the 2 miles I had on my drive to work and to get gas.”

   NHTSA complaint #11302521, filed 2020-01, 1,118 miles

   “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. …”

   NHTSA complaint #11746751, filed 2026-06
5. 5
   Brakes

   Parking brake or brakes applying without input

   • 6 complaints (6%)
   • median 4,788 mi at 0.7 yrs old (4 state mileage, few)
   • filed 2019–2026

   Owners describe the parking brake engaging on its own while driving or while parking on an incline, requiring manual release or placing the vehicle in gear to move again. Others report the brake pedal losing hydraulic pressure and sinking toward the floor, accompanied by ABS and stability control warnings, with normal function returning after a restart. Complaints also mention the vehicle slowing or braking when the accelerator was pressed, and dealers in some cases could not determine a cause. Reported from very low mileage up to around 16,000 miles.

   What to check: Test the parking brake on a slope and confirm it releases normally, and ask whether any brake, ABS, or stability-control repairs or software updates have been performed.

   2 excerpts from owner complaints in NHTSA records

   “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. …”

   NHTSA complaint #11763346, filed 2026-09

   “Recently purchased a 2020 Acadia denali. When parking at any incline the parking brake automatically turns on. Dealer is not sure why, but no where in the manual does it state this is normal. To disengage brake vehicle has to be put in gear with foot on brake to turn off. The parking brake should turn off when vehicle is in park with foot on brake but it does not. Dealer is unsure of issue and has an open case with Gmc to investigate.”

   NHTSA complaint #11282398, filed 2019-11, 20 miles

Buying note. A 2020 Acadia with documented service history is worth prioritizing: ask specifically whether the thermostat and thermostat housing, transmission fluid or torque converter, and the fuel pump recall have been addressed. A thorough test drive covering steady-speed cruising, cold-start A/C performance, and every door lock and display is the most useful check before buying.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.