Global Powertrain Engine Controller (GPEC) Powetrain Control Module (PCM) Flash Process Failure: "Negative Response 0x12 - 'Sub Function Not Supported / Invalid Format' Received from Security Request Download Request"

VEHICLES: 2007+ vehicles equipped with Global Powertrain Engine Controller (GPEC) ECU: GPEC ISSUE: Flashing a GPEC PCM may result in an error message of “negative response 0x12 - 'Sub...