Outback F4-2.5L (2008)
Technical Service Bulletin # WVU-31
Date: 110322
Campaign - ECM Update, Cold Weather Emissions Function
NUMBER: WVU-31
DATE: March 2011
APPLICABILITY:
2006-10 MY Legacy, Outback,
Forester & Impreza with a
25 Liter N/A engine only
SUBJECT:
Engine Control Module (ECM) Reprogramming
SERVICE PROGRAM BULLETIN
INTRODUCTION
Subaru of America, Inc has determined that vehicles affected by this Service Program require ECM reprogramming
A modification to the Engine Control Module software logic has been developed to improve the performance of the emission control system. This
software change will not adversely affect fuel economy or performance.
This software update is intended to improve vehicle emissions when the vehicle is operated in cold weather and the engine is turned off and restarted
within short periods of time such as in several minute intervals. The A/F sensor contains a heating element which is controlled by the ECM, and which
assists the sensor in reaching an optimum temperature resulting in better accuracy. When the vehicle is operated under the conditions described above
there could be a longer than desired delay in the ECM's turning on the A/F sensor heating element, resulting in higher than desired emissions. This
software enhancement will correct that condition.
Please note the following special information concerning affected vehicles and the availability of ECM reprogramming PAK files.
AFFECTED VEHICLES
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20062010 MY Subaru Legacy Outback, Impreza & Forester with 25 Liter normally aspirated engine only. Models with 6 cylinder or turbo charged
engines are NOT affected.
Affected vehicles are identified in the VIN range chart below. Prior to performing repairs, confirm coverage by using the Vehicle Coverage Inquiry
function at Subarunet.com.
