2021 Subaru Ascent: adaptive cruise control problems

Filed Oct 31, 2026 · Driver assistance · ID · crash · 1 injury

2021 Subaru Ascent was involved in a serious collision with highway maintenance equipment near [XXX]. The vehicle's EyeSight Driver Assist Technology, specifically Adaptive Cruise Control and Pre-Collision Braking, is suspected of failing to respond appropriately to slower-moving equipment directly ahead. At the time of the collision, Adaptive Cruise Control was actively engaged and controlling vehicle speed. Lane Centering, Lane Departure Warning, and Lane Keep Assist were also enabled. The vehicle was traveling within its designated lane when it approached a highway maintenance truck equipped with a rear-mounted crash attenuator. The maintenance truck appeared to be moving slowly in the same lane. Despite Adaptive Cruise Control controlling vehicle speed, the Subaru did not adequately slow to avoid the collision. The driver reported no effective forward collision warning or automatic emergency braking intervention. Whether the system detected the equipment or attempted braking is UNKNOWN. The impact caused extensive front-end damage and airbag deployment. The driver was pregnant, and two children, ages [XXX] and [XXX], were passengers. All occupants and the unborn child were placed at significant risk of serious injury. Whether any EyeSight warnings, fault messages, or diagnostic trouble codes were present before impact is UNKNOWN. The suspected malfunction has not been reproduced or confirmed by a dealership or independent service center. A manufacturer engineering inspection has not been confirmed. Photographs document the accident scene and vehicle damage. The extent of police or insurance technical inspections and the vehicle's current availability for inspection are UNKNOWN. An investigation is requested into Adaptive Cruise Control, forward object detection, and Pre-Collision Braking, including preservation and review of available electronic collision data to establish why the systems did not prevent or effectively mitigate the collision. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (F

Filed Nov 30, 2022 · Acceleration, Driver assistance · MO

Adaptive Cruise Control, Automatic Emergency Braking, Forward Collision Warning, Lane Departure Warning, Lane Keeping Assistance, Eye Sight, RAB, some ! Symbol, and check engine light are all on and not working. You know everything that makes a Subaru. This is not the first or even second time. We are on the fourth instance of this happening. We live 2+ hrs away from the closest dealers. The first few times it occurred, we called to make a appointment. Each time was always a few weeks out and the issue would clear a day or two before. This last time has been going on for 6 weeks. We both work full time and have a very sick kid so making a appointment is hard. This last time I asked if I can drop in just for a scan due to being in town for an appointment. Was met with we are backed up with way to many repairs. Also it would not be fair to any other people. It is most likely your gas cap. I have made sure the cap is tight as it can get every time from the first time it occurred. So all safety features on the Subaru Ascent just stop working if the cap is not tight. Not only is this a major safety issue their QA is asleep at the wheel. Known issue, just check the forums.

Filed May 14, 2021 · Driver assistance, Steering · 140 miles · CA

Lane assist with cruise control over corrects. On multiple occasions while on the freeway using cruise control the lane assist pulled me into the other lane into other vehicles. I have almost hit other vehicles. The pull is too strong and crosses lanes. If not fixed by subaru, accidents will occur.

Filed Apr 18, 2021 · Driver assistance · 1,500 miles · CA

Lane assist with cruise control over corrects. On multiple occasions while on the freeway using cruise control the lane assist pulled me into the other lane into other vehicles. I have almost hit two other vehicles. The pull is too strong and crosses lanes. I have to keep it off. Forward collision does not engage.

Filed Mar 17, 2021 · Driver assistance · 5,000 miles · WA

The lane assist feature (only an option when using adaptive cruise control; not the same as lane centering when not using the adaptive cruise control [the basics lane centering works just fine]) seems overly aggressive. Each time I have used lane assist with cruise control, it jerks the car very abruptly at times, almost to the extent of sending it into another lane if I do not intervene. I no longer feel safe using lane assist, so I turn it off when using cruise control. I am very concerned it's going to cause and accident. This has happened at least 5 times now while driving on the freeway (every time I have attempted to use lane assist).