Subaru Outback battery drains. Causes and fixes

Subaru Outback, the versatile and comfortable crossover SUV, is popular for its reliability. But, like all vehicles, it’s not immune to problems, such as a draining battery.

This issue can have various causes, making it imperative to comprehend the root cause to find a proper resolution. This article delves into the diverse reasons for a draining battery in a Subaru Outback, along with providing fixes for each.

A Weak Alternator

The alternator, accountable for recharging the battery while the engine is running, may be the culprit if weak. When the alternator falls short, it may not recharge the battery completely, causing a drain.

The signs of a weak alternator include flickering lights, slow-moving accessories, and warning lights on the dashboard. To rectify this predicament, you’ll need to replace the alternator.

The cost of replacing the alternator can range from $400 to $600, depending on the model and the labor involved.

Parasitic Load

A parasitic load refers to electrical components that keep consuming power even after the vehicle is turned off. Examples include the radio, clocks, and other electrical devices.

To fix this, you must determine the component causing the drain and disconnect it. In some instances, you may have to install a switch to turn off the device when the vehicle isn’t in use.

Corroded Battery Connections

Battery connections that are corroded can result in a drain. The corrosion can prevent the battery from recharging and can also create resistance in the electrical system, leading to a drain.

To resolve this, you must clean the battery connections and tighten them to secure a connection. This fix is relatively simple and inexpensive and can be done either at home or by a professional.

Malfunctioning Battery

A battery that is failing or has reached the end of its life can be the cause of a drain. This can occur due to various reasons, including age, deep discharging, or exposure to extreme temperatures.

To fix this issue, you’ll need to replace the battery, which can cost anywhere from $100 to $200, depending on the model and the type of battery.

Faulty Starter Motor

The starter motor, responsible for starting the engine, can cause a drain if faulty. If the starter motor is faulty, it may continue to draw power even when the engine isn’t running.

The signs of a faulty starter motor include a clicking sound when turning the key, slow cranking, and grinding noise. To fix this issue, you’ll need to replace the starter motor, which can cost anywhere from $500 to $800, depending on the model and the labor involved.

Leaking Power Steering Fluid

Although rare, a leaking power steering fluid can cause a battery drain. This can occur due to a leak in the power steering pump, hose, or rack and pinion.

To fix this, you must locate the source of the leak and repair or replace the affected component. The cost of fixing this issue is quite high, ranging from $200 to $1,000 or more, depending on the severity of the leak and the labor involved.

Leaving Lights On

Forgetting or leaving the lights on when the vehicle is turned off can cause a drain on the battery. This is a common cause of a draining battery and can be easily remedied by simply turning off the lights before exiting the vehicle.

If it’s left like this for too long a jump-start is required to start the engine.


In conclusion, a draining battery in a Subaru Outback can have a variety of causes, ranging from a weak alternator to leaving the lights on.

Understanding the root cause of the issue is crucial to finding the right solution. By following the fixes outlined in this article, you can prevent battery drain and ensure your Subaru Outback is always ready to go

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