2020 GMC Acadia Owner Complaints

[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.

NHTSA ID

11749841

Incident

Apr 9, 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.

NHTSA ID

11748973

Incident

Feb 1, 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.

NHTSA ID

11748881

Incident

Apr 22, 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.

NHTSA ID

11746751

Incident

Mar 1, 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!

NHTSA ID

11745760

Incident

Jun 22, 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

NHTSA ID

11741177

Incident

Apr 1, 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.

NHTSA ID

11738492

Incident

May 1, 2026

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.

NHTSA ID

11736917

Incident

May 15, 2025

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.

NHTSA ID

11736892

Incident

Apr 15, 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.

NHTSA ID

11734889

Incident

Apr 14, 2026

Mileage

61,699 mi

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

NHTSA ID

11734822

Incident

Oct 1, 2025

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.

NHTSA ID

11732081

Incident

Feb 20, 2026

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!

NHTSA ID

11731342

Incident

Mar 9, 2026

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

NHTSA ID

11729759

Incident

Mar 21, 2026

Thermostat

NHTSA ID

11729140

Incident

Aug 3, 2025

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.

NHTSA ID

11724868

Incident

Mar 6, 2026

Mileage

47,000 mi

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

NHTSA ID

11724282

Incident

Mar 14, 2026

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

NHTSA ID

11724079

Incident

Feb 23, 2026

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.

NHTSA ID

11722524

Incident

Mar 6, 2026

Mileage

68,140 mi

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 ID

11722466

Incident

May 2, 2025

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

NHTSA ID

11722457

Incident

Feb 23, 2026

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.

NHTSA ID

11718069

Incident

Feb 14, 2026

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.

NHTSA ID

11717537

Incident

Jan 31, 2026

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.

NHTSA ID

11717530

Incident

Jan 31, 2026

After heavy rain or a carwash, the door locks and lift gate don't work from key fob. And the vehicle says no remote detected and has trouble starting. After a day or two they start working again. It caused U0422 (invalid data received from body control module). On forums it says it can be water leaking into the vehicle and shorting out the BMC from either the HVAC drain or a weatherstrip somewhere. Now my rear passenger door locks don't work at all. Dealer wants to replace the actuators but can't find the root cause of the problem. Issue has been going on for over a year now.

NHTSA ID

11714468

Incident

Oct 1, 2024