What 207 owners told NHTSA about the 2021 Subaru Forester Wilderness

My 2021 Subaru Forester has a recurring, worsening defect in the Idle Stop/Start (ISS) system that creates a stalling hazard. When ISS shuts the engine off at a stop, the engine intermittently fails to restart when I try to move again. It cranks progressively slower, warning lights illuminate, a continuous alert sounds, and the vehicle cannot proceed until I shift to Park and restart manually. This has left me immobile in live traffic at lights, stop signs, and mid-turn. The system also attempts to shut down in unfavorable moments, such as mid-turn, or as I am already releasing the brake (meaning it was depressed only lightly or briefly); it then tries to restart while still mid-shutdown, producing a pronounced shake. This is not a battery-charge problem. It has occurred even when the battery tested above its rated cold-cranking amps, and after each failure the engine restarts smoothly by manual start, indicating the starter, engine, and fuel systems function normally. I raised this before 2024, but it was not recorded until May 2024. At that visit the dealer performed the TCM reprogramming in Service Bulletin 16-147-24 (Forester, auto start/stop engine speed drop on restart) plus an ECM update. A later visit added another ECM update. A dealer has now identified yet another TCM reprogramming, quoted for a fee. The failure has persisted across all of these updates. Dealer staff acknowledge repeated customer complaints with these exact symptoms and say there is no known effective fix. Because ISS cannot be permanently disabled through any factory control, I must remember to disable it manually every drive to avoid a restart failure in traffic. The vehicle is available for inspection. This is an ongoing, unresolved safety defect that repeated manufacturer software remedies have failed to correct, and it can leave the vehicle disabled in live traffic.

NHTSA ODI 11748058

The contact owned a 2021 Subaru Forester. The contact stated that while driving at approximately 4 MPH and slowing to park, the vehicle accelerated on its own. The contact stated that the vehicle drove out of the parking lot and crashed into a wall. The contact stated that the air bags deployed and that the vehicle had then shifted into reverse (R) and driven out away from the wall and crashed into a parked vehicle and stopped. The contact stated she was unaware of any warning lights. The contact stated that she had 1 passenger in the front seat and 2 passengers in the rear seat. The contact stated that everyone was shaken and achy, but no cuts or other injuries. The contact stated later that the passengers went on their own to seek medical attention. The contact stated that the passenger front bumper, hood, and wheel well were damaged, and the rear bumper on the passenger side had damage from the crash with the parked vehicle. The contact stated that the other vehicle had minor damage to the right rear quarter panel. The police were called and issued a report. The vehicle was towed to a collision repair shop, but had not been repaired. The vehicle had not been diagnosed for the independent acceleration and reverse failures. The contact stated that her insurance provider had not yet declared the vehicle a total loss. The manufacturer was not informed of the failure. The failure mileage was approximately 30,000.

NHTSA ODI 11723858

On 8/12/15, I had stopped at a stoplight. When the light changed and I attempted to move forward with traffic, the Eyesight Disabled warning came on and my car completely stalled and refused to move. The car prompted me to put it into park, I attempted this and it did not resolve the issue. After this, the car prompted to press the start/stop button. This also did not work. I eventually had to completely turn off the car while in an active lane of traffic and turn it back on. This resolved the issue. In less than 24 hours, I was at the dealership. They have been unable to determine what caused the vehicle to effectively shut off while idling. They are performing a TCM update and do not appear to believe the issue is a safety issue, however again the vehicle stalled in an active lane of traffic during rush hour. It felt like when the car goes into the gas saving mode while idling but this had not happened. It just stopped. This was an extremely unsafe situation to be in a car that can not move or have to try and get it into neutral and get it out of traffic on a busy road, moments after being on the highway. The dealership checked the battery twice and confirmed that it was functioning and I have the video walk through where the confirm the car is in good condition and they could not replicate the issue.

NHTSA ODI 11680508

The Thermo Control Valve failed and the engine overheated in April 2025. The car has only been driven 1,200 miles since then and the engine failed at 65,000 miles likely due to the TCV failure and engine damage.

NHTSA ODI 11674825

At 40936 the valve body needed to be replaced. With such low milage vehicle is having problems.

NHTSA ODI 11633969

Having repeat issues with the windshield cracking. My vehicle has around 32k miles, and I'm already on my 3rd windshield. I've never had this issue with any other vehicle. It's been extremely costly. Also the transmission failed and had to be replaced at 26,000 miles.

NHTSA ODI 11625815

The 2021 Subaru Forester had been functioning normally with no warning lights. About 25 minutes into the drive I had come to a stop light on an upward incline. When the light turned green I moved from the brake to the gas as usual. However the auto-start function on the car failed, causing the engine to stall. A loud clunking sound was heard and the dashboard lit up with multiple lights, although I do no recall which ones were illumined. I attempted to press the gas again and the car did not respond. During this short time my foot was pressing on the gas the car rolled backwards and collided with the vehicle behind me. I continued attempting to press the gas pedal and still no acceleration was made. After parking and restarting the car it has resumed normal function. I have not yet visited the dealership so this issue has not yet been reproduced, nor has the offending system been inspected. I'm summary, the automatic engine start failed at a critical location, putting myself and others in serious danger and ultimately caused a crash.

NHTSA ODI 11571429

Once or twice a day my vehicle hesitates from a light and I have to almost floor it to get it going again.I have brought it to 2 different Subaru dealers 3 times and they say they can't fix the problem.

NHTSA ODI 11569468

Thermo control valve failed at about 42000 miles on 2021 Subaru Forester Premium, on 1/1/24. Owned 3 yrs 1 mo. Car was parked at work. Immediately after car was started up for return commute -- check engine light was on, ADAS systems ("Eyesight") disabled, blue low coolant temperature light on, and no heat through HVAC. Fortunately car driveable, despite safety being compromised with disabling of the safety features (blind spot monitor, rear cross traffic alert) and concern about damaging engine being forced to drive home with check engine light on. Engine failed to warm despite 40+ min highway trip. As this was commute vehicle, forced to take next day off work to have check engine light looked at. The next morning windshield ice had to be manually scraped (no heat). Drove car gingerly to dealership (<10 mins) avoiding freeways, for fear of damaging engine. Unknown if windshield defroster would've worked if started fogging mid-trip (safety concern). Dealership inspected vehicle - diagnosed thermo control valve failure, and replaced part. I was not charged as the car was still covered under powertrain warranty. No warning prior to the failure. Drove normally on the morning drive to work. Dealership replaced TCV with a part that has the same part number, per Subaru's TSB. Given experience of others indicating high failure rates of TCV after 3-4 years, and what I suspect is genuine design defect, I expect replacing the part to only have temporarily reset the clock -- seems certain to fail again. I have no confidence that Subaru has implemented an actual solution. I do not know if the next failure of this powertrain component will happen under warranty, or if it will incur signficant out of pocket costs (well over >$1000 to replace). Furthermore, if TCV fails whilst driving (as could have happened, and has been reported by others elsewhere), this will be a safety hazard with sudden disabling of blind spot monitor / rear cross traffic alert.

NHTSA ODI 11564774

The contact owns a 2021 Subaru Forester. The contact stated while shifting the vehicle into the drive gear, the vehicle accelerated at high speed without any warning and drove into the wall of her garage causing front damage to the vehicle. The contact stated that the vehicle hesitated to turn off. No one was injured. The vehicle was not diagnosed. The dealer was not contacted. The manufacturer was not notified of the failure. The failure mileage was 8,000.

NHTSA ODI 11499550

The contact owns a 2021 Subaru Forester. The contact stated while depressing the brake pedal and attempting to park in the driveway, the vehicle excessively independently accelerated in speed. The brake pedal failed to stop the vehicle and the vehicle was shifted into Park in order to come to a stop. The vehicle caused damage to the door and garage. There were no injuries reported. The vehicle was not diagnosed. The dealer was contacted, and they stated they were not aware of any recalls or complaints for the failure. The manufacturer was not contacted. The failure mileage was 10,000.

NHTSA ODI 11496649

Car was parked on driveway (6 degree slope to rear) Car was placed in park Driver exited car to go into house when she came out car had rolled down the driveway to hit another car parked across street rear facing bot cars had rear damage. The same thing happened to the car one week later when parked in the garage placed in park but started to roll back. Was able to stop it because I was still in the car I use the parking brake now all the time

NHTSA ODI 11485237

On 04/02/2022, several minutes after having filled the gas tank, I was driving at about 35 mph on a two lane road at constant throttle, when the engine suddenly lost power for several seconds before it regained acceleration. There was a pickup truck following me very closely and it swerved around me to avoid hitting me. On 04/13/2022 , several minutes after leaving my driveway, at about 27 mph on a two lane road, the engine again lost power for several seconds before resuming power. In the first case the engine was at operating temp., in the second case it was cold. I will take the vehicle to the Subaru dealer from whom I purchased it in a couple of days to evaluate the problem, which I consider to be serious. In both cases I was so surprised that I didn't look at the tach etc. 12,500 miles.

NHTSA ODI 11462054

The vehicle gets a shudder at different speeds and it feels like it's either the transmission is slipping or its coming from the motor but it NEVER THROWS a Trouble Code so as the dealership says if its not throwing a trouble code they can't diagnose it until it does. So that's why I don't like these vehicles because no one know how to fix it old school by being a real mechanic and going old school to find the issue.

NHTSA ODI 11440297