DTC P0685: Powertrain Control Module (PCM) Power Control Circuit/Internal Circuit Malfunction: General Description

After the ignition switch is turned to LOCK (0) or the engine start/stop button is pressed to select the OFF mode, the powertrain control module (PCM) does not shut down immediately. After finishing a predetermined process according to the request of each device and system, the power supply is automatically disconnected (self shut-down function). The PCM power is disconnected by controlling PGM-FI main relay 1. During a normal PCM shut down, the shut down process is executed by the CPU, PGM-FI main relay 1 is turned off, and the voltage to the PCM is turned off to shut down the PCM. When the voltage to the PCM is turned off and the PCM shuts down without the normal shut down procedure, the PCM detects a malfunction in the PGM-FI main relay 1 control circuit and stores a DTC.