2021 Subaru Outback: battery drain or dead battery

Filed Oct 14, 2026 · Electrical · FL

Battery died multiple times. A DMC module went bad.

Filed Aug 26, 2026 · Electrical · VA

Vehicle's Auto Start-Stop system shut the engine off while stopped at a red light in [XXX], in rainy conditions in late XXX at approximately 29,000 miles. When the brake was released after the light turned green, the engine did not restart, leaving it stopped in the travel lane in live traffic. The driver had to use a portable jump starter to get it running again. This was not isolated — repeated failure-to-start incidents in prior weeks had already prompted carrying a portable jump starter in the vehicle. At the time we believed this was a failing 12V battery. The original battery was replaced XXX with a new aftermarket AGM battery. Despite that replacement, the vehicle has continued to have multiple complete battery drain if left parked for multiple days (but less than a week), indicating the restart failures were likely caused by an underlying parasitic electrical draw rather than a simple worn-out battery. Subaru's own Technical Service Bulletin 07-199-21R, "Measurement of Dark Current (Standby Current Draw)," describes this exact failure pattern (batteries/vehicles going dead over time due to standby current traced to the VDC module and/or Power Rear Gate control module) for this model and model-year range. A pending federal class-action lawsuit, [XXX] v. Subaru of America, Inc., Case No. XXX (D.N.J., filed XXX), alleges an electrical-system defect preventing one or more control modules from entering a proper low-power sleep state, causing parasitic battery drain, and specifically names 2021-2022 Outback vehicles. We are concerned this defect can cause the Auto Start-Stop system to fail to restart the engine at a stop in live traffic, creating a real risk of being rear-ended or blocking an intersection, as happened in the incident described above. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jun 15, 2026 · DE

First battery drain in car. Bought a new battery and it drained again for the second time. Called Suburu to ask about a parasitic drain from the DCM and they said it was likely that and told me to call Suburu America. Did that but they wanted me to take it to a Suburu dealer to get the problem verified. I don’t have the $ to do that. I notice there is a class action in court right now for this exact problem.

Filed Sep 16, 2024 · Electrical · UT

Battery keeps draining if car isn't driven for a few days battery is drained to point of it being dead, cannot get into car, will not start, leaves you stranded. This is the fourth time this year, dealer checks it out tells me nothing is wrong. I have read many problems with parasitic battery drain with subaru's even that the alternator is programed not to fully charge the battery to save gas. getting tired of the issue to the point where I am thinking of selling the car and finding something that will not leave me stranded. This time when I checked the battery voltage it was 5.80 volts and .29 amps.

Filed Aug 31, 2024 · Electrical · OH

Parasitic Draw on battery: Original battery was dead after sitting 5 days; Bought new AMG and it has also died after 4 days sitting.

Filed Aug 29, 2024 · Electrical · UT

Battery drains quickly and renders the car inoperable. Possibly due to Controller Area Network (CAN) not entering sleep mode when vehicle is not being used resulting in a parasitic battery drain.

Filed Aug 12, 2024 · WA

2021 Subaru Outback Limited | ~13000 miles | Component: Battery | Car suddenly stopped and ALL warning lights started flashing at a busy traffic signal, while I was waiting to take a left turn (lucky to have escaped safely from that situation). I had to turn the car off and restart it. 2 days later, the car would not start at all. Tried jumping it multiple time in vain. Had to tow the car to the nearest Subaru service center. Technician ran a diagnostic and concluded that the battery was not holding any charge at all and it was deemed faulty. Reading many posts on reddit and other forums of many Subaru owners facing the same issue from older (2015) to newer models. Many of them also complained of Parasitic drain on the battery due to faulty DCM on Starlink. Note: there was no warning lights/messages or any other symptom before this. This was a Subaru certified pre-owned car that went through a 152 point inspection in 2023.

Filed Jun 2, 2023 · Electrical · OK

Car would not start this morning. It’s driven every day, so it had not been sitting. Last service was 3/23 (today is 6/2/23), and the battery passed dealership inspection with no issues. Roadside serviceman stated this was the fourth “relatively new” Subaru he’d had to jump this week. Jumping the battery fixed the issue (for now), but the Subaru dealership, themselves, advised submitting a claim for potential “parasitic battery drain.” However, the current class action suit only covers 2015-2020 Subarus, and mine is a 2021 Outback.

Filed Jan 11, 2023 · Electrical · MI

Battery of the vehicle continues to drain itself at seemingly random times. All sources that could possibly drain the battery while vehicle is not running have been turned off (dome light, tailgate light, exterior lights set to minimum time, etc...). Several times, this drainage has resulted in the car having to be jumped, so driver can get home. Car has been taken to dealer. Dealer indicates battery is fine. Took home, a few days later, battery is dead. Car does seem to struggle to turn over at times when trying to start. Lately this has been noticed while driving the car, and it engine was restarting while shutting down at stoplight (shutdown as part of limiting emmissions); had to turn the automatic shut-down feature off. Contacted local dealer again, was told that nothing can be done if battery is tested and it tests fine. We have resorted to carrying a recharging pack with the car to ensure that our kids don't get stranded with a dead battery.

Filed Jul 14, 2022 · Electrical · NM

Battery is draining for no apparent reason. As stated in several class action law suits, defects in these vehicles ( Subaru Outback 2015-2020) cause the batteries to drain, replacement batteries also drain. The Subaru Outback battery drains because of the Controller area network (CAN). When the vehicle is shut off, the CAN system should enter sleep mode so only a limited amount of electrical current is used. However, Subaru software errors prevent the CAN from entering sleep mode when vehicle is turned off. This software error will drain the original battery and every replacement battery installed in an Outback. Once the battery is drained, I am stranded. Reference law suits Daley v. Subaru and Tomasian v. Subaru. Subaru needs to fix all Subarus that are affected by this battery drainage issue. I have been experiencing this problem since we bought the car. First time, I thought I left something on, subsequent drainage issues I know that nothing has been left on. I now keep a trickle charge unit on the battery while in the garage at all times.

Filed May 16, 2022 · Electrical · OH

vehicle about 14 months old, I purchased new Tried to start vehicle battery dead, no lights or other acc. had been left on. two weeks later battery would not start car, I jump started car according to directions in owners manual. After jump start several check engine lights came on, cruise control did not work. lane control and "EYESIGHT" failure warning light was on. Subaru dealer replaced battery under warranty

Filed Feb 21, 2022 · CA

The battery does not hold a charge. I have had to have AAA charge my battery on 10 occasions in the fourteen months since I purchased this vehicle. I also have had to have the battery jumped by friends to start the car. The battery was replaced by the dealership in early September 2021, claiming it was a deflected battery and I should have no more battery problems. The replaced battery has not held a charge either. There is no warning, just a dead battery. i have been informed by Subaru that the cause of a dead battery is because the car is not driven every day. I am retired and have no need to drive every day. However, when I have been able to start the car and use it frequently the battery still dies. The car is not safe to drive when the battery is unreliable.