Subaru of America, Inc. (SOA) is initiating a service program for certain 2017-2019 MY Impreza vehicles, and certain 2018-2019 MY Crosstrek vehicles. This service program involves installation of reprogramming files to optimize the ECM. Subaru has determined that due to an engine programming issue, the affected vehicles may stall when coming to a stop or driving at a low speed (under 15 MPH) when the air conditioning is operating at maximum capacity. Under certain hot weather conditions, when the vehicle?s air conditioning is running at full capacity, the engine programming may not account for the additional load placed on the engine when slowing down or coming to a stop. In some cases, this could cause the engine to stall requiring the driver to immediately restart the vehicle.