Subaru Forester battery drain problems

Filed Oct 8, 2026 · Electrical · NY

Experienced parasitic battery drain which disabled the vehicle. The drain is tied to a 30 amp fuse labeled "BACKUP" under the hood of the vehicle. This fuse controls the touchscreen, backup camera, interior lights, key fob and radio. There were no warning lights or trouble codes associated with this issue. The problem was replicated by both a Subaru dealer and an independent shop. Neither could find the immediate problem without further investigation, which would have cost more than $1000. I have not contacted the manufacturer, police or insurance rep. The car will operate with the fuse pulled but the safety features listed above will be disabled.

Filed Jun 17, 2026 · Electrical · NY

Persistent Battery Drain on a 2021 Subaru Forester Limited. Problems began in year 4 of ownership (~17,000 mileage), after Subaru Starlink Subscription services expired. Red (Error) Starlink SOS indicator light was evident, where a normal light would show green. Battery would fully drain after about 3-4 days of inactivity while parked in a commercial garage. After repeated dead batteries, a jump-starter battery pack was used regularly, as well as a wall-outlet battery charger. The problem has not resolved with a new and appropriately specified AGM battery, replaced in December 2025. The only solution is to pull the engine-bay fuse #5, which disables the Data Communication Module (DCM), as well as other features (hands-free microphones and audio system). By pulling the fuse #5 consistently, the problem has ceased, even after a two-week period of no use. This provides irrefutable evidence that the DCM powered by fuse #5 is the source of the battery drain. The only resolution Subaru would offer was to insist on a dedicated diagnostic visit to a dealership, with the associated costs of hundreds of dollars to be borne by me, the customer, without a clear understanding of the costs or remedies to resolve this problem. I feel unsafe driving my vehicle for more than short trips given the risk of stranding or further electrical malfunctions that would impact critical vehicle functions or safety systems.

Filed Jun 3, 2026 · Electrical · FL

2021 Subaru Forester The vehicle has experienced recurring electrical and battery-related issues for several years. The original battery was replaced by the Subaru dealer with a larger-capacity battery because of repeated starting concerns. The replacement provided only temporary improvement. The vehicle continues to experience rough starting on a regular basis, even after installation of a newer aftermarket battery with a higher cold-cranking-amp rating. The current battery is approximately five months old. The most significant safety concern occurs during Auto Start-Stop operation. On multiple occasions, the engine has shut off at a stop as intended, but then failed to restart when attempting to move again. When this occurs, multiple warning lights illuminate on the dashboard and the vehicle is unable to proceed until it is shifted into Park and restarted manually. Because of this issue, I now disable the Auto Start-Stop feature on every drive to avoid a potential failure to restart while in traffic. The issue has been ongoing for years and has occurred with multiple batteries, including the dealer-installed replacement battery and a newer aftermarket battery. The dealer suggested that an aftermarket dash camera could be contributing to battery drain. The dash camera was disconnected, but the problem continued. I am concerned that failure of the vehicle to restart after Auto Start-Stop operation could leave the vehicle disabled in traffic and create a safety hazard. The condition appears to involve the vehicle’s electrical system, battery management system, charging system, Auto Start-Stop system, or a combination of those components. The vehicle is available for inspection upon request.

Filed May 11, 2026 · Electrical · CA

June 2025: I proactively replaced the battery October 2025: Left the car parked for 17 days. Dead battery. Got a jump, drove for 2 hours. May 2026: Left the car parked for 10 days. Dead battery. Got a jump, drove to mechanic who replaced it under warranty. Saw article about Subaru class action lawsuit about this issue, so I'm reporting it. I will visit the Subaru dealer where I purchased to car and ask them about it and Subaru's plans for permanent repair.

Filed Apr 3, 2026 · Electrical · MI

We have replaced the battery twice and likely will need a third battery soon. I have learned that there is a known issue with the DCM trying to connect using 3G. This is causing a parasitic drain on the battery. The vehicle will fail to start. This has occurred many times over the last few years. We have just learned of the problem.

Filed Mar 12, 2026 · Driver assistance · VA

My 2017 Subaru Forester Touring (VIN: [XXX] , 118,200 mi) has a recurring EyeSight failure where the system becomes disabled and will not complete camera registration or calibration. Subaru of Sterling (VA) diagnosed active code B28A0 “Vehicle Model Judgment” and noted that the EyeSight stereo camera would not accept vehicle model registration. The technician documented: “Error for camera adjustment incomplete. When attempting to relearn UI for Eyesight camera, system is not taking vehicle registration; suggests camera replacement and perform recalibration.” This occurred after a confirmed DCM/STARLINK parasitic draw had caused repeated low‑voltage conditions until the dealer reset the DCM to factory mode (per the RO: “No further draw present at this time”), suggesting EyeSight registration may have failed due to prior voltage instability rather than true hardware failure. Subaru's service flow for B28A0 indicates this code can occur when the model write/registration is incomplete, interrupted, or mismatched—not necessarily when a camera has failed. Subaru lists causes such as: CAN communication issues, incorrect model registration, incomplete write due to ignition timing, or power/fuse issues during aiming (EyeSight diagnostic manuals). I am reporting this to the federal safety agency because EyeSight is a safety-critical system that governs adaptive cruise, lane keep assist, and pre-collision braking. My dealer is recommending camera replacement without documenting that Subaru’s required pre‑replacement steps (model registration inspection, CAN/LAN re-scan, voltage and fuse verification, genuine-part verification, etc.) have been completed. I request ODI review because EyeSight should not fail to register unless hardware is defective or a procedural/voltage issue exists. I want this documented in case this represents a broader pattern of EyeSight registration/calibration failures on Forester models using the same stereo camera platform. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Feb 20, 2026 · Airbags, Electrical · NY

The airbag system has a sensor issue and I keep getting warnings from Subaru to get it fixed because it affects the seatbelts. The garage where I take my car says they are unable to get the part needed for the passenger sensor. And, Subaru says they need to replace the whole harness for $6000. Makes me wonder why a safety issue like this one seen in other Subaru’s have been recalled but not my model… Also the start stop feature drains the battery excessively. I have had to replace the battery twice in less than a year. I push the button to stop this feature the minute I get into the car.

Filed Feb 3, 2026 · Electrical · WA

The defect presents itself when the equipped data communications module (DCM) attempts to communicate with 3G cellular networks. As 3G networks within the U.S. are no longer functioning, the call will continuously fail even after the vehicle has been turned off, draining the battery and resulting in a no-start safety risk for drivers but in order to replace the DCM to the 4G it will cost upwards of $2000.

Filed Dec 2, 2025 · Driver assistance, Electrical · MD

Two incidents happened first battery died, we replaced the battery. Then Battery died again, we replaced the alternator on June 5, 2025. Then on Saturday September 13, 2025; all system lights came on at once on the dashboard then the battery died again. Car locks up and is stalled out. Cannot restart car, has to be towed. We replaced the battery cable and cleaned the terminals. Three months later, December 1, 2025; the battery light came on then all system lights came on at once, the battery died again. This happened on Interstate 95, it could easily have caused a crash. Car locks up again and is stalled out again. Cannot restart car again, has to be towed again. Something in the electrical is causing this, we do not know what.

Filed Nov 1, 2025 · Electrical · ID

The defect presents itself when the equipped data communications module (DCM) attempts to communicate with 3G cellular networks. As 3G networks within the U.S. are no longer functioning, the call will continuously fail even after the vehicle has been turned off, draining the battery and resulting in a no-start safety risk for drivers. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)