2021 Subaru Forester engine 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 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 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 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.

Filed Apr 17, 2026 · Engine, Fuel system · VA · fire

While driving this car on April 4, 2026 at around 6PM, I experienced the distinct smell of gasoline. I had driven for about 5 minutes on our way to a local restaurant that is approximately an 8 minute drive from our residence. My wife said that she had just filled the gas tank that afternoon. After arriving at the restaurant, I checked the gas cap to ensure it was tightly sealed. I also checked to ensure no fuel was leaking from the car. After finishing dinner, we I drove the car back to my residence and once again, 5 minutes into the drive, I smelled gasoline. After we arrived home, I check the vehicle exterior for leaks and found no liquids under the car. The following day, April 5, 2026 at approximately 1115 AM, having once again found no liquids or gasoline under my car, I drove the car to my local repair shop; an 8 minute drive. About 5 minutes into the drive, I smelled gasoline again. I parked the car at the repair shop, but while adjusting the parking to fit better between the painted lines, I saw and heard a large puff of smoke from the hood area. I immediately put the car into Park, shut off the engine and ran from the car. After exiting, I saw that the car ignited with visible fire under the engine compartment. I called 911 to request fire department help. No damage to any structures or other cars occurred. Q1 Above: No the car is totaled and unavailable for inspection as far as I know. Q2 Above: I had to run from a burning car. Q3 Above: No. Q4 Above: Yes, the car was inspected by my insurance company, USAA. Q5 Above: No, there were no warning lights or any indictor that there was trouble. I would like to note that the car was brought in to my Subaru dealership service station (Hyman Brothers in Midlothian, VA) for a heater element safety recall several months ago.

Filed Apr 2, 2026 · Engine · WA

While driving the car, the engine stops completely. After a few seconds, it can be restarted. It does this several times a week at random intervals. It's very dangerous since it usually happens when we're driving in traffic. The dealer checked it out in July but couldn't find anything wrong. Even though it's a serious safety problem, they said to keep driving it until it does it every time the car is driven or until the car won't run. When this happens, all the dashboard warning lights come on and the word "Eyesight" is displayed with a diagonal line through it. A warning buzzer also sounds. This started last summer with very infrequent occurrences and is now several times a week.

Filed Apr 1, 2026 · Electrical, Engine · TN

Automatic start/stop fails to turn car on - intermittent. Taken it to Subaru detailer miltiple times and paid for services to correct the issue, but the issue persists. Fist time - replaced the battery in July 2025. 2nd time, went on a ride along for 1 hour, issue did not happen, replaced spark plugs, issue persists. 3rd time, updated TCM software, issue still persists. Subaru of America is aware of the issue and have not gotten a resolution either.

Filed Mar 12, 2026 · Engine, Transmission · 30,000 miles · IL · crash · 4 injuries

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.

Filed Feb 1, 2026 · Electrical, Engine · TX

Car drains battery. 45,000 miles and has had 3 batteries and have been told it needs another. Dealer says start stop switch, requires a battery of 750 CCA and not the Subaru recommend battery. Car will die in traffic and driver seat adjusts to different positions by itself. Told that these problems will never stop unless I get a higher rated battery than required.