Defects in the Subaru's Electrical System Constantly Drain the Underpowered Batteries

Posted on
Scott McCracken
Overhead view of the battery inside a Subaru engine

You're going to need a bigger boat battery

Too many Subaru owners are finding their cars with dead batteries and unable to start. The batteries aren't defective, but just lack the capacity to handle the draw from the car's electrical systems, particularly while the vehicle is turned off.

Some say their batteries will drain every few days, forcing owners to constantly jump their own vehicles or install trickle chargers at home.

The Batteries CAN Not Handle the Load

The batteries are draining due to issues with the vehicle's controller area network (CAN). A CAN system helps all the electrical units, microcontrollers, sensors, and actuators communicate with each other.

The system is adequately powered while the vehicle is running, but should enter a sleep mode when the vehicle is turned off. But according to multiple class-action lawsuits, the system either doesn't have a proper sleep mode or has software errors that prevent it from properly conserving power.

Instead, the system continues to draw power from the battery which is known as a parasitic drain. By the time an owner gets back to their car, there's not enough power to crank the engine.

Subaru has allegedly known about this issue since 2014.

Replacement batteries are nice, but don't solve the problem

To their credit, Subaru has offered to replace some dead batteries under warranty.

But the batteries aren't defective, they just don't have the necessary capacity and aren't designed to continually be drained down to low volumes of power. As the parasitic drain continues, the batteries lifespan is shortened. And there's only so many times it can be jumped before it just gives out altogether.

So replacing the OEM battery with another that has the same cold cranking amps, reserve capacity, and amperage hours, just won't work in the long term.

Subaru vehicles with drained battery problems

The following vehicles have all had complaints about drained batteries, although the Ascent and Outback appear to have the most issues overall.

  • 2019-2020 Ascent
  • 2015-2020 Forester
  • 2015-2020 Legacy
  • 2015-2020 Outback
  • 2015-2020 WRX

Lawsuits Regarding This Problem

Lawsuits about this problem have already been filed in court. Many times these are class-action suits that look to cover a group of owners in a particular area. Click on the lawsuit for more information and to see if you're eligible to receive any potential settlements.

  • Partially dismissed

    Tomasian, et al., v. Subaru of America, Inc.

    1. Partially dismissed

      After being consolidated with another lawsuit, the case was partially dismissed because some of the plaintiffs do not allege their vehicles continued to have problems once Subaru made repairs.

    2. Case Filed

      Subaru dead battery problems have caused a lawsuit that alleges 2016-2020 Subaru Outback and 2019-2020 Subaru Ascent SUVs are equipped with batteries that drain and die.

    Class Vehicles
    • 2019-2020 Ascent
    • 2016-2020 Outback
    New Jersey
  • Partially dismissed

    Dalen, et al., v. Subaru of America, Inc., et al.

    1. Partially dismissed

      After being consolidated with another lawsuit, the case was partially dismissed because some of the plaintiffs do not allege their vehicles continued to have problems once Subaru made repairs.

    2. Case Filed

      A class-action lawsuit was filed because of battery problems in certain Subaru vehicles because the automaker's decision to install batteries with insufficient capacity to power the vehicle's electrical components when turned off.

    Class Vehicles
    • 2016-2019 Outbacks
    • 2020 Ascent
    New Jersey

Generations Where This Problem Has Been Reported

This problem has popped up in the following Subaru generations.

Most years within a generation share the same parts and manufacturing process. You can also expect them to share the same problems. So while it may not be a problem in every year yet, it's worth looking out for.

What Owners Say About This Problem

Twice my 2020 Subaru Ascent's battery has been dead. It has been driven every day for at least 20-30 minutes. Nothing was left on, or open. There is obviously an elecrical issue draining the battery.

2020 Ascent Owner

This is the third time I have had to deal with a dead battery for the car. I don't drive it often, and the car runs absolutely fine when the battery is actually working, but the battery dies on its own which leads me to believe that it's somehow draining on its own. There has got to be a recall about this soon.

2018 Outback Owner

The battery has drained down twice in the same week. Car is only 6 months old. Nothing plugged in. Very annoying. I had Subaru Roadside Assistance tow it 45 miles to nearest dealer. We will see what happens. Clearly a defect in the 2019 Subaru Outback.

2019 Outback Owner

OK, Now What?

Maybe you've experienced this problem. Maybe you're concerned you will soon. Whatever the reason, here's a handful of things you can do to make sure it gets the attention it deserves.

  1. File Your Complaint is a free site dedicated to uncovering problem trends and informing owners about potential issues with their cars. Major class action law firms use this data when researching cases.

    Add a Complaint
  2. Notify CAS

    The Center for Auto Safety (CAS) is a pro-consumer organization that researches auto safety issues & often compels the US government to do the right thing through lobbying & lawsuits.

    Notify The CAS
  3. Report a Safety Concern

    The National Highway Traffic Safety Administration (NHTSA) is the US agency with the authority to conduct vehicle defect investigations & force recalls. Their focus is on safety-related issues.

    Report to NHTSA