Engine Controls - Engine Speed Stability Unification
NUMBER: 11-107-11DATE: 11/01/11
APPLICABILITY:
2011 MY Forester 2.5L N/A
2011 MY Legacy and Outback 2.5L N/A
SUBJECT:
Program for Unification of Engine Speed Stability
INTRODUCTION
With the release of the October 2011 Subaru Select Monitor III (SSMIII) software update and Flash Write reprogramming software updates, a new logic revision was added for the above listed models. "Improvement of Engine Speed Stability" and "Program for Unification of Engine Speed Stability" is designed to homogenize across all model lines an update previously incorporated in other models. The purpose of this change is to improve the engine speed stability under idling conditions when the transmission gear shift position is changed from "N" to "D". Under normal conditions, when the transmission gear shift position is changed from "N" to "D" the target engine speed is changed just after the transmission clutch is engaged. However, in cases where the catalyst warmed-up signal is input to the ECM during the delay time (i.e timing between gear position signal is changed and transmission clutch is engaged), the target engine speed does not change as desired To improve this condition, the target engine speed calculation procedure has been modified. Though this change affects only automatic transmission models, the ECU of manual transmission models have also changed in order to homogenize the ECU programming logic across all models. This calibration change is designed to have no effect on emissions or fuel economy.
REPAIR PROCEDURE/INFORMATION
This particular logic update does not address any concern that would be noted by the customer. As such, installation of this file in and of itself is not required. Installation of this file should only be necessary when addressing another concern that is outlined within the descriptive comments for the same file. (e.g. 22765A13404 for 2011 Forester 4AT also addresses P0128, so if a qualifying vehicle is presented for this code then this reprogramming should be used, but if the same vehicle is presented with no DTCs then this file does not require installation)
In conjunction with this change the part numbers of ECU's are changed as shown.
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