2.5 Liter N/A engine only. REVISED. 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.
