2020 Subaru Forester: adaptive cruise control problems

Filed Oct 26, 2026 · Driver assistance, Engine · FL

On XXX, while driving my 2020 Subaru Forester Sport (VIN [XXX]) at approximately 35 mph on [XXX], the check engine light came on and EyeSight, adaptive cruise control, and pre-collision braking were disabled / other warning lights appeared / engine temperature issues. A diagnostic scan showed code [P2682 / P26A3 / P26A5], and the Thermo Control Valve (TCV) was found to be defective. Mileage at failure: 33,297. Subaru has acknowledged this defect in Technical Service Bulletin 09-119-24, which extends warranty coverage for the TCV on 2019–2021 Foresters to 15 years/150,000 miles. However, Subaru of America denied coverage and goodwill (case XXX) because the vehicle was originally sold in [XXX] through Subaru’s independent distributor, Trebol Motors, before I moved to [XXX] in XXX. This failure disables key safety systems without warning and should be addressed through a safety recall that covers all affected vehicles, including those sold in U.S. territories. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Apr 4, 2025 · Acceleration, Driver assistance · SC · crash

I was on cruise control, and it randomly decided to go 81 MPH instead of 50 mph i set it to, it did not respond when I tried to turn off the cruise control, and I ended up crashing into a semi, I survived but my [XXX] daughter died. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Dec 3, 2024 · Driver assistance, Engine · NJ

"Check Engine" light along with "Eye Sight" appeared suddenly on Nov. 22, 2024. All safety systems along with cruise control became inoperable. Took car to Subaru dealer and it was confirmed to be the catalytic converter. My VIN is covered under extended warranty, but I was never notified of this. Plus, now repairs are of an emergency nature. Also, I do a lot of driving including on the NJ Turnpike, I-95, etc., and while I am awaiting car to be repaired, I have no safety features to rely on--which was one of the reasons I bought a Subaru. They will not pay for a courtesy car loan. Another issue is the Thermo Control Valve. I was notified that I have an extended warranty for this, but part has to FAIL before Subaru will make repairs. Once again this becomes an emergency repair situation instead of a proactive one.

Filed Nov 9, 2024 · Engine · LA

DEFECTIVE THERMOSTATIC CONTROL VALVE- This part NEEDS to be recalled. Manufacturer has extended the warranty on the part, so it was free to replace. Otherwise, it's a $1600 part. I'm thankful they covered the price, but upset that this KNOWN issue is preventable and they've been letting people continue to be put in danger for four years now?! Incident 1) I was driving 45 mph on a busy street when the car bucked & All engine lights turned on (not helpful to pinpoint a problem) EyeSight turned off (when I needed it most.) The car was worse than dead. I was desperate to get to the shoulder, so I slammed on the emergency lights. Horrified, I realized turning the wheel did almost nothing. I had to lean on the steering wheel to get to the shoulder. When I applied gas it would choppily accelerate, so instead i let the car coast. Since i had no gas, i was stuck in the middle of a side road. I put it in park and turned it off. Someone started walking up from the bad neighborhood, wanted me to get out so he could push the car. I said no, but It took a few minutes to talk him into leaving through the glass of my window. But, this time when i started it up the dash warning lights were off Incident 2) between Oct& Nov 2024 Intermittently all the dash lights turned on, no cruise control or Eyesight. Resolved on its own. No engine trouble acompanied these. Incident 3) Nov 5th, 2024. I started my car, warmed it up, and drove for about 3 minute's when all the dashlights lit up, Eyesight failed, and the whole engine acted like it was on choppy seas. This was at night in a rural area and I was barely able to guide the car to the right shoulder because the accelerator was not working at all. Ended up slashing up my tire and ruining my rim on the shoulder of the road since the car was barely maneuverable. I could have been killed or in an accident - where is the recall on this part?? Mileage at total failure : 46,434

Filed Jun 24, 2024 · Driver assistance, Electrical · NY

Within one month the same thing happened. I turn on the car and the eyesight warning light is on (eyesight feature disabled), flashing "S" drive is on, "break" light is on, and check engine light is on. Due to this cruise control isn't working. My plan was to take it to a mechanic/dealership that Monday. By Monday morning, after about 15 minutes of driving, all warning signs disappeared. This exact thing happened a few weeks later (this morning). I started googling issues and seems like this is an issue for many customers and is just a malfunctioning Thermo Control Valve, no actual problem. What do I do about this? This is much less important - but also seems like a quality issue, at drivers side, the seat cover is starting to crack, looking like this is car is over 10 years old, we've had it for less than 4 years and this shouldn't be happening on a car of this caliber. Photos attached

Filed Mar 20, 2024 · Transmission · WA

The thermo control valve failed causing the coolant to run at full and not allowing the engine to reach proper temperature and the heating system to not provide heat, also it caused multiple safety systems to turn off including eye sight, emergency braking, rear auto brake, lane keeping, adaptive cruise control, traction control. the failure of this unit is a known issue to Subaru per their own service bulletin 09-80-21, while mine was not covered by Subaru's own warranty due to the mileage this vehicle is less than 5 years old, the repair costs will be $2000.00+ as quoted by the dealer.

Filed Feb 8, 2024 · Driver assistance, Engine · CA

The thermal control valve stopped working. The car has <50K miles on it. The error also results in many/all of the safety systems being deactivated (no adaptive cruise control, no lane centering, no rear braking, etc.)

Filed Nov 30, 2023 · Transmission · VA

The Thermo Control Valve failed at 33,945 miles. Because of this, the heater, Eye Sight, Cruise Control, Lane Assist, and Collision Brake did not work. The engine was then only running at "Sport" mode. It did not regulate the heat to the oil and could've caused sludge. The problem was confirmed by a Subaru Dealer Service Shop. I only noticed this problem when the blue thermometer light came on the dash board. Usually I wait about 5 min and once the car is warmed up the light goes away. This time the blue thermometer warning light did not turn off and stayed on for the remainder of the trip. When the car was restarted on the same day the engine check light came on. Eye Sight, Lane assist and Collision assist lights were on.

Filed Nov 8, 2023 · Brakes, Electrical · NY

The thermo control valve malfunctioned causing the check engine light to come on which shut down all the safety features in the vehicle including the front eye sight camera, blind spot warning, the rear automatic braking, lane departure warning, adaptive cruise control, and lane keeping assistance.

Filed Sep 19, 2023 · Driver assistance, Engine · GA

The thermo control valve malfunctioned causing the check engine light to come on which shut down all the safety features in the vehicle including the front eye sight camera, blind spot warning, the rear automatic braking, lane departure warning, adaptive cruise control, and lane keeping assistance. The check engine computer readout diagnostic trouble code was P26A5 "Engine Coolant Bypass Valve "A" Position Sensor Circuit Range/Performance". The vehicle was taken to a Subaru dealer who found the thermo valve performance was out of spec. This vehicle has not been recalled although the manufacturer replaced the part in 2021 vehicles acknowledging the valve was faulty. Because of the mileage on my vehicle, it was not covered under the warranty although many have been replaced under the manufacturer's warranty due to the failure of this valve under the 60,000 mile warranty. I believe this should be a recall item for others who experience this issue.

Filed Aug 30, 2023 · Transmission · MO

The thermo control valve malfunctioned causing the check engine light to come on which shut down all the safety features in the vehicle including the front eye sight camera, blind spot warning, the rear automatic braking, lane departure warning, adaptive cruise control, and lane keeping assistance. The check engine computer readout diagnostic trouble code was P26A5 "Engine Coolant Bypass Valve "A" Position Sensor Circuit Range/Performance". The vehicle was taken to a Subaru dealer who found the thermo valve performance was out of spec. The valve was replaced. This vehicle has not been recalled although the manufacturer replaced the part in 2021 vehicles acknowledging the valve was faulty. Because of the mileage on my vehicle, it was not covered under the warranty although many have been replaced under the manufacturer's warranty due to the failure of this valve under the 60,000 mile warranty. Through a "Goodwill gesture" Subaru replaced the part in my car at no cost. I believe this should be a recall item for others who experience this issue.

Filed Mar 23, 2023 · Engine, Seats · 47,000 miles · OH

The contact owns a 2020 Subaru Forester. The contact stated while driving 35-38 MPH in cold weather, the temperature gauge indicated that the vehicle temperature was cold. The check engine warning light was illuminated. Additionally, the Forward Collision Avoidance system, the Lane Keep Assist, the Auto START/STOP feature, the cruise control mode, and other unknown features no longer operable messages were displayed. Additionally, the vehicle shifted into Sport (S) mode. The contact was able to drive to her residence. The vehicle was taken to the dealer, where it was diagnosed that the thermal control valve needed to be replaced. The contact stated that there was an inch-long slice like cut in the front passenger's seat. The vehicle was not repaired. The manufacturer was notified of the failure via mail. The failure mileage was approximately 47,000.