2021 Subaru Forester problems

Filed Nov 1, 2026 · Electrical, Engine · TX

When coming to a stop, the auto start/stop system shuts the engine off and it fails to restart. All dashboard warning lights illuminate. The vehicle must be shifted to Park and restarted manually with the start button. The component that failed is the auto start/stop system; the exact cause is UNKNOWN. The vehicle is available for inspection upon request. This put safety at risk because the vehicle was left immobile in live traffic at stops until it could be restarted. There were no warning lamps or symptoms before the failure; the warning lights come on when the failure occurs. The vehicle was inspected by Gillman Subaru Southwest on October 229, 2026, and the dealer stated the battery performance was bad and in critical condition.

Filed Oct 28, 2026 · Engine · CO

Component Failed & Inspection Availability: The vehicle suffered a sudden, catastrophic mechanical engine block failure at 74,000 miles. The dealership teardown confirmed a failed/spun lifter bearing and a fractured connecting rod cap, requiring a complete engine replacement. This sudden oil pressure failure/blockage occurred while the engine oil pan was verified completely full. This sudden mechanical failure is directly consistent with severe localized thermal breakdown from a failing Thermo Control Valve (TCV)—a component subject to Subaru Warranty Extension WMM23—or loose factory RTV silicone debris clogging the oil galleries. The failed components, including the engine block, rod cap, and TCV, have been retained by the owner and are fully available for inspection upon request. Safety Risk: The engine failed catastrophically and seized instantaneously while driving at highway speeds, causing a sudden and total loss of motive power. This created an immediate hazard as the vehicle rapidly decelerated in active traffic without warning, blinding drivers behind me and stripping the vehicle of power steering assist. This forced a dangerous maneuver to navigate the disabled vehicle through highway traffic to the shoulder, significantly risking a severe rear-end collision. Dealer Confirmation & Inspection Status: The problem and point of failure were officially confirmed and documented via a physical engine teardown conducted by a certified Subaru dealership service center. Subaru of America Corporate Advocacy was notified under Case Number 260818-1500487 but denied coverage. The components have not been inspected by the police or insurance representatives, but they remain preserved as physical evidence. Warning Lamps & Symptoms: There were no warning lamps, check engine lights, low-oil indicators, or abnormal electronic codes prior to the instantaneous mechanical failure. The vehicle had been professionally serviced and oil-changed just 3,800 miles prior to the breakdo

Filed Oct 28, 2026 · Transmission · 66,902 miles · GA

The contact owns a 2021 Subaru Forester. The contact stated that while driving and accelerating from a stop, the vehicle started bucking and hesitating. The vehicle was taken to the local dealer to be diagnosed, and it was determined that the transmission control valve body was inoperable and needed to be replaced. The transmission control valve body was replaced and the vehicle was repaired. The manufacturer was notified of the failure and informed the contact that the repair was not covered under an extended warranty associated with the failure. The failure mileage was 66,902.

Filed Oct 25, 2026 · Electrical, Engine · RI

I was stopped at a red light. When the light changed to green I put my foot on the gas and the car totally stalled out. There were no lights, fans or radio on just total silence. I tried to restart the car putting it is park and depressing the brake while pushing the start button and nothing. It didn't even try to turn over. silent, dead. I tried several times with no luck. I got out of the car to signal to the bus and row of cars behind me to pass me. I got back into the car and tried to start it again and this time it started. I drove immediately to the mechanic near my house. They couldn't see what was going on without me leaving the car next week. The battery had been replaced 6 months ago. This was a busy intersection and I was worried about getting out of the car but I had no choice.

Filed Oct 21, 2026 · Body · CT

There’s two brackets that are at the top of the tailgate, and also at the top of the body where they meet to match up, The bracket on the right sits flush, the bracket on the left since indented about a 1/4” give or take. Because it’s painted by the factory, there’s no cracks around the bracket and the paint, meaning it happened at the factory. I’ve looked at other cars that are in that same model year bracket between 2018 and 2025, and they’re all variations of the Subaru Forrester. Didn’t matter if a sport or limited any of that. They all have the same indented left hand bracket that is causing mold on the interior of the car, some worse than others, and I spoke to the people that own the cars, the ones that are parked in a garage or car covered, they have less mold, the people that parked their cars outside have more mold. But they all have the same bracket on the left-hand side that is screwed up. I’m attaching photos to show the amount of mold damage we have taken, and so much more.

Filed Oct 11, 2026 · TX · 1 injury

Driver side rear window spontaneously failed while driving on the highway. Passenger experienced cuts due to glass fragments

Filed Oct 5, 2026 · Transmission · SC

The transmission very suddenly (perfectly fine one day, bad the next) developed a severe transmission slip. Like getting rear ended feeling transmission slip. Dealership quotes the CVT control valve body.

Filed Oct 3, 2026 · Engine, Fuel system · CA

On two separate occasions, less than one year apart after Subaru Service replaced my battery with a “larger” battery without my knowledge my vehicle suffered sudden, catastrophic electrical failure while moving in active highway traffic, causing an immediate loss of propulsion and creating a life-threatening safety hazard. This has happened two times the second time less than a year after the “larger” battery replacement. This car has less than 50,000 miles on it and has a perfect service record all done at AutoNation Subaru Carlsbad. We refuse to drive this car, even though it has been serviced and a new battery has, yet again, been installed. We have no faith in this car and are not willing to put ourselves in a life-threatening situation again. We also do not feel comfortable selling this car, even though we have received many above market offers. We do not feel that we can sell this car in good conscience to an unknowing next victim. It is unsafe to drive and can lose power at any moment while driving without any explanation given from Subaru. The first battery failure occurred prematurely in August 2025. Asked repeatedly why a car battery would fail while driving? Could not get a straight answer except that someone finally said it could possibly be from the auto stop start system The new larger battery failed less than one year later in August 2026, so it didn’t even last a year and it was larger. The service department at AutoNation Carlsbad told me my car passed all the test and I have nothing to worry about. This goes against any common sense. How could this happen 2 times where no issue has been disclosed. Both situations were extremely traumatic and dangerous and I feel lucky that I was able to come out of it. I’m not sure the next time would be the same. We are not able to drive this car because common sense tells us there is a bigger issue going on. So far we’ve communicated with Subaru of America and were denied California Lemon law without reason.

Filed Jul 7, 2026 · Electrical · 22,500 miles · MA

The contact owns a 2021 Subaru Forester. The contact stated that while trying to roll up vehicle windows from driver sits and passenger sit they would roll up to 3/4th all the way up and they would roll back down after. The contact stated this was a recurring event. The dealer was aware of failure and diagnosed issue needing repairs for window regulator and run channels for driver and passengers side. Manufacturer was made aware of failure and let contact know it was outside of warranty. The failure mileage was approximately 22,500.

Filed Jul 2, 2026 · Electrical, Engine · WI

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.