2020 GMC Acadia

While idling, my vehicle has a strong exhaust smell inside the cabin. Per the GM Dealer, this is due to faulty flex hose.

On multiple occasions the car will suddenly brake or like throw on the parking brake and stop suddenly no warning

I bought the car at the end of October 2025, so it was always cold till last month. Last month the first day it’s warm I get a warning saying my steering assist has been limited with a code saying the thermostat needs replacing as well as the sensor. This is a known issue with these vehicles and now I have to pay $1500 out of pocket to have fixed because my limited warranty expired 2 weeks before it was warm enough to trip the codes. This is ridiculous especially seeing as I am disabled and can’t afford an extra $1500 after spending $7000 for the down payment!

The contact owns a 2020 GMC Acadia. The contact stated that the doors failed to open from outside the vehicle while using the key fob or while attempting to open the doors manually. The contact entered the vehicle from the rear hatch door and discovered that the door lock and unlock buttons were inoperable. The contact pulled the door handle to manually open the door from the inside. The cause of the failure was not yet determined. The manufacturer and local dealer were notified of the failure, but no assistance was provided. The failure mileage was 68,140.

The contact owns a 2020 GMC Acadia. The contact stated that the AC was inoperable. The message “Driving Assist Reduced - Drive with Care” was displayed. The vehicle was taken to the local dealer, where it was diagnosed, and determined that the battery needed to be replaced. The vehicle was not repaired. The vehicle was taken to an independent mechanic who replaced the battery. While driving, the message "Driving Assist Reduced" was displayed. The contact was concerned about driving the vehicle due to the failure of the steering wheel. The contact stated that the failure was related to GM Special Coverage: N252508350. There were four attempts to contact the manufacturer, but there was no response. The failure mileage was approximately 47,000.

My 2020 GMC Acadia slt has a a warning message that pops up on the dash display which reads power steering operating at reduced assistance. Please proceed with extreme caution. At high speeds the wheel kinda pulls and is loose for handling. It also atfff conley buick out by the conley buick sericexx2020 acadias. I don't not54⁴ lower rates of speed becomes extremely hard to maneuver . Almost zero ability to turn the steering wheel. I'm disabled and really can't afford the costly repair. It seems to be a very dangerous problem and well known to compromise ones ability to control the 2020 Acadia danalis. I had my suv ckd out at conley buick the results were power steering module needs to be replaced. When driving down the road the steering becomes dangerously loose especially

Check engine light codes: P01F0; P0128 Engine coolant thermostat opening at a lower temperature than intended. Replace thermostat.

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.

Reduced steering assist came up on screen then as we went a few more miles the tire pressure on right front dropping like crazy for no reason on screen in vehicle stopped looked at tire no issues.

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. Recently, a code was finally set P01F0, so I had something tangible to take into shop as the prior condition was not repeatable. Hoping it was only the coolant temperature sensor, then ultimately learned the thermostat had failed - the much more expensive repair option. Seeing this complaint relatively frequently with the 3.6L engine on NHTSA. Plus, the tech says he has changed at least 100 of these - Acadias, Traverses, Enclaves, etc., any GM product with this engine and poor design/position for the thermostat.

Rear heater line leak detected during evaluation of engine code P01F0 and empty expansion tank was noted. There was never any puddle in my garage prior to the incident, and nothing detected after the fact either. Pictures included demonstrate a leak at the double-crimp near the farthest rear point of the vehicle. The other hose behind the drip photo was also leaking at the crimp under the secondary piece of hose insulation. The design of the system requires replacement of the entire heater line assembly (4 pipes, associated hoses and fittings) traversing the entire length of the vehicle. I was told this is a dealer-only part.

My front camera that detects the front collision and helps with adaptive cruise control just went dark. I thought maybe it would reset after turning engine off and restarting it, but it didn’t help. Not sure what happened.

The "Steering Assist is Reduced" warning came on the same time the engine thermostat display stopped working. Then the check engine light came on the same time the AC stopped working. At first I thought maybe it was just the battery, so I had that changed out. But the "Steering Assist" warning continued and the engine thermostat display was still stuck on "Cold" no matter what (note: the oil temp display still worked fine). Looking in to the problem, apparently a defective Engine Thermostat is a pretty common issue with this vehicle. Why isn't there already a recall on this? The risk of engine overheating is HUGE and dangerous. I called GMC and they want to charge and arm and a leg to fix it (the car has 47000 miles so is just out of warranty). I don't want to wait until there is an accident to have something done about this.

The contact owns a 2020 GMC Acadia. While the vehicle was at the dealer for maintenance, the contact was informed that the radiator was leaking and needed to be replaced. In addition, the contact was advised that there was coolant intrusion. The contact stated that it was not specified if the coolant intrusion had gone into the engine. No warning lights were illuminated. The vehicle was not repaired due to the cost. The contact was informed that the fueling system needed cleaning service, as well as the brake fluid and transmission fluid needed to be serviced. The vehicle was taken to several independent mechanics, and no leaks were found with the radiator. The manufacturer was not made aware of the failure. The failure mileage was approximately 62,000. The VIN was not available.

1. Shift to Park failure, P0700/P187e internal sensor, causing me to have to get a rebuilt transmission. 10/2025 2. Transmission shudder/hard-shifting ongoing 2022-2025 3. Coolant/thermostat issues. Steering Assist Reduced" message, fans stay on HIGH, no AC, engine temp on ZERO ongoing since 2024 3. Start/Stop button failure multiple times (replaced 3 times) 4. Rack and pinion/steering gear (would not return/ got stuck while turning) got new rack and pinion 2023 5. Water pump leaking, replaced 4/2024 6. Since 2023, have had ongoing “Timing OVER ADVANCED”, warning issues since 2023. This is TOO MUCH for a New car!!! I’ve owned MANY cars and NEVER had this many issues!!! There appears to be multiple design flaws with this model and similar models!

Car keeps throwing Poo14 code for VVt sensor, I’ve replaced the sensors and checked wiring on the side of the road and no damage found, went online and read multiple complaints and recalls on the same issue I’m having with my car. I enter my vin and no recalls have been found. I have a 2020 gmc Acadia Denali 3.6l v6. As well and the rear view camera cutting in and out multiple times anlmost causing an wreck. and a system update didn’t fix the issue.

Thermostat

Vehicle will shutter or buck at variable speeds like, 35-38 mph, 40-45 mph and so on. if I take my foot of the gas and reapply it will shutter buck again at almost any speed. I took it to a mechanic and there are no codes, no check engine light. Shop recommended changing the transmission fluid so we did. Car still responds the same way, shutters and bucks when reapplying fuel pedal or slow acceleration.

I'm not sure of the exact sequence of events here, but there are multiple exhaust leaks. One is a crack somewhere in the catalytic converter that is now leaking exhaust from the back of the engine into the passenger compartment. The other leak is at the point of a bracket which fastens the two front exhaust pipes together. At the time we first noticed an exhaust leak sound upon cold start, there were are around 58,000 miles on the car. Now a month later there are still less than 60,000 miles on the car. The dealership originally estimated repair costs to replace the catalytic converter and two front pipes at $3,200. When I had another service garage look at the problem, they asked why the GMC dealer wasn't willing to replace the catalytic converter under the 80,000 mile / 8 year warranty. When I raised this with the dealership, they said this was a "gray area" becasue they believe what happened was that the exhaust bracket at the front pipes failed first, which then caused the catalytic converter to crack. Ultimately, they indicated they would be willing to pay parts and labor related to the catalytic converter (approx $2,000) if we paid the other $1,200 to cover the front pipes. What I don't understand is why, when both Chevrolet and Buick have extended their front pipe warranties on comparable model years of the Chevy Traverse and Buick Enclave, which use the exact same part numbers for the catalytic converters and pipes to 150,000 miles/15 years, why GMC has not offered the same special coverage on the Acadia. Regardless of which cracked first, the front pipe bracket or the catalytic converter, there is likely an engine vibration/movement issue that casues the cracks, giving rise to exhaust venting into the passenger compartment. Since we have yet to be able to schedule the repair (catalytic converter was on back order), we can now only drive the vehicle with the windows down to lessen the exhaust smell. The Acadia deserves a Special Coverage Advisory on this.

Valve body car would not go in park