If you’re the proud owner if a 2006-2010 four-cylinder Legacy, Outback, Impreza or Forester, there is a new alert you should know about so you can bring in your Subaru for a system update. Subaru has issued bulletin WVU-31 about the Engine Control Module (ECM). Here’s what you need to know about this alert and what to do if your vehicle is affected.

What the WVU-31 bulletin says

Most NA (naturally aspirated) four cylinders in the listed model types and years are affected. A defect prevents the front Air/Fuel sensor from reaching optimal temperature early in the start-up cycle. This issue means the emissions expelled are higher than they should be but does not impact the operation of your Subaru. But since it does affect air quality, it’s important to correct.

The error only affects your vehicle under certain conditions. When you run your Subaru in cold weather or when you turn your engine off and on within a short period, the defect allows higher than expected emissions. When the defect triggers, there may be a delay in the ECM turning on the A/F sensor heating element which leads to higher than targeted emission levels.

Subaru’s fix for this error

Subaru has developed a modification with a software fix that reprograms the Engine Control Module of certain 2.5 liter naturally aspirated four-cylinder engines in Legacy, Impreza, Forester and Outback manufactured between 2006 and 2010. The software modification will improve the emission control system performance.

It’s important to note that this correction will not change the fuel economy or performance of your Subaru. The software tweak will clean up emissions, and no hardware maintenance or repair is required. Also, be aware that if your Subaru is a six-cylinder, turbocharged, Baja or Tribeca model your engine is not affected and does not require service under this bulletin.

How do I get my Subaru serviced under this bulletin?

You can bring your vehicle into any authorized Subaru dealership for the software update. The process should take less than an hour, but you should talk to the dealer shop for scheduling details. This update should be performed free of charge. Subaru mailed out notices about the ECM issue and the software fix, but not all owners have brought their vehicles in for service.

If you purchased your Subaru used, the software fix might have already been done – check your vehicle’s maintenance records either in the hard copy that came with your car or online at Subaru.com using your registered VIN. If you’re concerned about Seattle’s air quality, this is not a maintenance notice to ignore!

Everyday maintenance and repairs for your Subaru

While you need to see an authorized Subaru dealer for the WVU-31 fix, for other repairs and maintenance, you can choose an independent shop. By choosing a trusted independent service center over a dealer shop, you can usually save time, money, and hassle without violating your warranty to keep your Subaru road-ready.

Next time you need an oil change, maintenance or repair on your Subaru, see the experts at Suburb Service. We’re the oldest independent Subaru service center in the Pacific Northwest and have been a Subaru-only shop for more than 25 years.

Click here to schedule an appointment with Suburb Service or call (206) 364-8089 to reach us in Seattle or dial (360) 659-6208 for our Marysville location. We’ll take good care of you and your Subaru.