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Some problems are easy to fix, especially when it comes to modern cars and SUVs. The Outback from Subaru is a modern vehicle that sometimes requires those easy fixes. Every vehicle is susceptible to a check engine light or two, so don’t fret! There are a few common reasons for the Subaru Outback check engine light to come on; let’s check it out.

One Subaru Outback check engine light cause is the gas cap

This Subaru Outback has some check engine light problems
A Subaru Outback | Subaru

A loose gas cap is a common reason your Subaru Outback check engine light (CEL) might come on. This is an easy fix, and you only need to tighten the gas cap. Most of the time, the light will go off after the gas cap is replaced and tightened.

Modern Subaru Outback vehicles have many sensors around the car to help keep them running their best. These tend to wear with age, and if a sensor starts to malfunction, it can throw a CEL. If a critical sensor goes, Mike Shaw Subaru says, you might notice a decrease in fuel economy or other issues that can impact driveability.

Here are some other common problems that can set off a check engine light on any car, but especially the Subaru Outback.

Ignition systemEmissionsSpark plugsFuel system
O2 SensorLoose gas capBatteryEngine cooling
Common Subaru Outback Check Engine Light Causes

If something is amuck within the electrical system, this can also throw a check engine light. The best way to remedy this situation is to use a scanner to get information. You can pick up an OBD2 scanner online or at a few local shops that will allow you to scan the Outback CEL code for more details. If you don’t have one of these scanners on hand, the local Subaru dealership or a mechanics shop might have one.

The most common Subaru Outback check engine light causes

Inside the Subaru Outback check engine light headquarters
The dashboard of a 2016 Subaru SUV | Matt West/MediaNews Group/Boston Herald via Getty Images

If you notice that your Subaru Outback check engine light is on, the list of potential reasons is long. One of the most common reasons on the Outback is related to the 02 sensors (or oxygen sensor). These sensors are on every modern car, but the Outback seems to be at odds with the system frequently.

If the vehicle is having issues with the oxygen sensor, that means something is off with the exhaust and fuel situation. Most Subaru Outbacks have two sensors, one before the catalytic converter and one behind the cats. If either one senses something is off, it can throw a CEL.

Subaru has issued service bulletins for this in the past, including the 2015-2016 Outback. This bulletin noted that a crack in the exhaust pipe can result in a deterioration of emissions performance. While most vehicles probably had this addressed back when the bulletin was issued, it could have slipped by some owners for one reason or another.

What else can cause a check engine light on the Outback?


The 3 Most Reliable Subaru Outback Model Years Under $10,000

Even though some Subaru Outback check engine light causes might be easily fixable, some require immediate attention. The CEL can come on if the coolant temperature sensor detects that there is something unusual happening. You’ll want to address this immediately, as it can cause the engine to run improperly if it overheats too much.

Sometimes, newer Subaru Outback models will be able to offer clues via a dashboard message. This isn’t the case with older models that might not have a digital dashboard that can display messages. No matter what is causing your check engine light to go off, don’t let a problem linger for too long. What was a simple fix can snowball into a bigger issue before you know it.