DTC P0685: ECM/PCM Power Relay Control Circuit/Open [11/2021 - ]: Procedure

1. Check the connecting condition of ECM connector.

   Is the ECM connector correctly connected?

   Result	Proceed to
   Yes	A
   No (Connect the ECM connector correctly.)	B

Result: 

B 

CONNECT THE ECM CONNECTOR CORRECTLY 

Result: 

A 

See step  2

1. Turn the ignition switch to OFF.
2. Remove the EFI MAIN relay.
3. Disconnect the connector from ECM.
4. Measure the resistance between the ECM connector and engine ground.

   Connector & terminal

   A5-12 (SSHUT) - Engine ground

   Is the resistance 1 MΩ or more?

   Result	Proceed to
   Yes	A
   No (Repair the short circuit to ground in harness between ECM connector and No. 1 engine room relay block and No. 1 junction block assembly (EFI MAIN relay).)	B

Result: 

B 

REPAIR HARNESS OR CONNECTOR 

Result: 

A 

See step  3

1. Turn the ignition switch to ON.
2. Measure the voltage between ECM connector and engine ground.

   Connector & terminal

   A5-67 (VBEC1) - Engine ground

   A5-68 (VBEC2) - Engine ground

   Is the voltage 10 V or higher?

   Result	Proceed to
   Yes (Repair the short circuit to power supply in harness between ECM connector and No. 1 engine room relay block and No. 1 junction block assembly (EFI MAIN relay).)	A
   No	B

Result: 

A 

REPAIR HARNESS OR CONNECTOR 

Result: 

B 

See step  4

1. Turn the ignition switch to OFF.
2. Check the EFI MAIN relay.

   Refer to PROCEDURE - Step 1

   Is the check result OK?

   Result	Proceed to
   Yes (Repair the poor contact of ECM connector.)	A
   No (Replace the EFI MAIN relay.)	B

Result: 

A 

REPAIR CONNECTOR 

Result: 

B 

REPLACE EFI MAIN RELAY