DTC P0685: Engine Control Module (ECM) Power Control Circuit/Internal Circuit Malfunction: General Description

After the ignition switch is turned off, the engine control module (ECM) 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 ECM power is disconnected by controlling PGM-FI main relay 1 (FI MAIN).

During a normal ECM shut down, the shut down process is executed by the CPU, PGM-FI main relay 1 (FI MAIN) is turned off, and the voltage to the ECM is turned off to shut down the ECM. When the voltage to the ECM is turned off and the ECM shuts down without the normal shut down procedure, a malfunction in the PGM-FI main relay 1 (FI MAIN) control circuit is detected and a DTC is stored.