2020 Subaru Forester: sudden loss of power

Filed Sep 10, 2026 · Engine, Transmission · MI

Component/System Defect: Failed Thermo Control Valve (TCV) leading to sudden vehicle power loss / limp mode. Description of Safety Incident: While operating my vehicle at highway speeds late at night, the Thermo Control Valve (TCV) failed catastrophically without warning. The vehicle instantly experienced a massive loss of engine power and entered an aggressive "limp mode," causing a drastic, uncommanded deceleration in active traffic lanes.Due to the sudden reduction in speed and the low-visibility night conditions, a commercial semi-truck traveling directly behind my vehicle was nearly unable to brake in time and narrowly avoided rear-ending us. My family—including an elderly senior and a [XXX] child—was trapped inside the vehicle during this near-miss collision. The vehicle became an immediate hazard on a high-speed highway. The authorized dealership subsequently confirmed a failed Thermo Control Valve (TCV) and replaced the unit under Subaru's extended warranty program. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 17, 2026 · Engine · CO

My 2020 Subaru Forester Sport suffered catastrophic engine failure on 6/19/2026 at 156,322 miles, 15 days and 1,031 miles after a thermo control valve (TCV) repair performed at an authorized Subaru dealer on 6/4/2026. The TCV is a known defect covered under Subaru TSB 09-119-24 (extended coverage to 150,000 miles/15 years). I never received mailed notification of this TSB and therefore did not seek repair within the covered window; Subaru approved the repair as a goodwill exception. While driving on I-70 westbound near Genesee, CO, on a sustained mountain grade with my family in the vehicle, I heard a loud noise. The oil temperature spiked to approximately 280°F, warning lights illuminated, and the vehicle lost all power in highway traffic. Losing propulsion on a steep grade in mountain traffic created a serious risk to my family and surrounding vehicles. Post-failure condition: empty coolant reservoir, coolant-contaminated (milky, green-tinted) oil, and metal debris on the dipstick, consistent with cooling-system failure causing engine seizure. I have timestamped photos. The engine is locked and the vehicle inoperable. The vehicle was towed to the same authorized dealer on 7/9/2026. The dealer's technician confirmed the engine is seized and requires teardown ($3,302.95) for full diagnosis; the dealer states teardown proceeds only on authorization from me or Subaru of America. I opened a case with Subaru of America on 5/26/2026 and formally requested in writing that Subaru authorize the teardown, with a stated deadline. As of 7/17/2026, the dealer confirms Subaru has sent no authorization or any communication during the week the vehicle has been on their lot. My written deadline, follow-up call, and final written notice went unanswered. The vehicle and all components are preserved at the dealer and available for inspection upon request.

Filed Jun 3, 2026 · Engine · OR

Vehicle entered limp mode at highway speed (approximately 70 mph) on [XXX] freeway in Washington State, it felt like I had rear ended a vehicle it shut down so hard. This was due to mis diagnosed inspection and service repair from a local Subaru Dealer. Vehicle lost power rapidly, creating a dangerous safety situation. Root cause traced to TCV/PCV system defects previously documented by authorized Subaru dealers. Previous Subaru authorized dealer replaced a torn PCV hose but did not diagnose the problem causing the tear. The dash warning lights were still illuminated after the diagnostic and repair when vehicle was picked up after service. I have attached a more detailed overview of the dangerous situation. The car finally lost power on the freeway while I was in the fast lane pushing 70 miles an hour. I was in the fast lane and with no power I had to cut across both lanes of traffic and get to the shoulder. I was 45 minutes from my home and it was dark, raining and the Subaru would not start. I called a mobile mechanic I found online who came out to the freeway, roadside, where I was stranded. He worked on the car for a couple of hours in the rain. He got the car to start but it would not stay running. I had the car towed to a friend's house in Vancouver, WA about 6 miles from where it had broken down. The same mobile mechanic came out and changed out one of the oil actuators and cleaned and replaced two of the OCVs then flushed the oil system and put new oil in the car. Cleared all the codes. The car starts, idles and will drive up to about 1500 rpm’s but any more than 1500 rpm’s and it dies. It's in limp mode and will move past those rpm’s. The warning lights and the PCV house splitting must have been signs of something else being wrong. That is the discussion I had with Wilsonville Subaru. They diagnosed the vehicle and let me know the PCV hose was the problem. Car was towed to [XXX] in Vancouver, WA sitting since April 15th, 2026 INFORMATION REDACTED PURSUANT TO THE FREEDOM OF IN

Filed Dec 3, 2024 · Electrical · CA

My car completely lost power. I had driven to the stop light and was waiting when it lost power. It had no power for several minutes and was unresponsive to the ignition or anything else.

Filed Dec 11, 2023 · Electrical · NV

Vehicle continuously suffers a total loss of power (engine shuts off) while driving, creating obvious hazard to the user of the car and other drivers. This continues to happen without warning and often while driving through intersections and other dangerous situations. No warning lights precede these events. We brought the vehicle to the Subaru dealership and, after testing/diagnosing the problem, they informed us the vehicle needs a larger battery (which also requires installation of a larger battery tray) than the one that came equipped with the vehicle from the manufacturer. No aftermarket modifications have been made to the battery or electrical systems and the current battery is the size and type recommended by Subaru in the owner’s manual; the dealership, however, advises that that battery is insufficient and needs to be changed for a larger-sized battery.

Filed Jun 23, 2023 · Engine · NJ

While driving on an Interstate highway the engine suddenly lost power and various warning lights lit up on the dash, including brake, eyesight, RAB. Managed to limp to the shoulder without getting hit and had the car towed to the dealer, who replaced the thermo control valve assembly under warranty.