DTC P0685 (Flash Code 416) ECM Power Relay Control Circuit/Open (RZ4E-TC)

1. Engine control system check

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) Diagnostic system check-engine controls".

2. Current DTC check

1) Connect the scan tool.

2) Turn OFF the ignition switch for 30 seconds or more.

3) Turn ON the ignition switch.

4) Observe the DTC information with a scan tool. Is a DTC set?

Yes

=>Go to ECM main relay inspection.

No

Go to Intermittent conditions of engine.

Refer to "202.Engine 15D.Symptom(RZ4E-TC) intermittent conditions of engine".

3. ECM main relay inspection

1) Turn OFF the ignition switch for 30 seconds or more.

2) Replace the ECM main relay with a known good relay.

3) Turn ON the ignition switch.

4) Observe the DTC information with a scan tool. Is a DTC set?

Yes

=>Go to Fuse inspection.

No

Replace the ECM main relay.

=>Go to Repair verification.

4. Fuse inspection

1) Inspect for a blown out ECM 40A slow blow fuse. Is the result normal?

Yes

=>Go to ECM ground inspection.

No

Replace the slow blow fuse. If the slow blow fuse blows out again, repair the short to ground in the circuits relating to the ECM 40A slow blow fuse.

=>Go to Repair verification.

5. ECM ground inspection

1) Inspect the ECM ground section for corrosion or improper installation. Is the result normal?

Yes

=>Go to ECM main relay circuit inspection.

No

Repair the ground point as necessary.

=>Go to Repair verification.

6. ECM main relay circuit inspection

1) Inspect for poor connections at the ECM harness connector (pins 2, 5, 21, and 40 of C7). Is the connection status normal?

2) Inspect each relay circuit for an open circuit or high resistance for the following. Is the result normal?

  • Between the ECM (pins 2 and 5 of C7) and the ECM main relay (pin 2 of the Fuse and Relay Box (Engine Compartment) ECM MAIN)
  • Between the ECM (pins 21 and 40 of C7) and the ECM main relay (pin 3 of the Fuse and Relay Box (Engine Compartment) ECM MAIN)
  • Between the ECM 40A slow blow fuse and the ECM main relay (pin 1 of Fuse and Relay Box (Engine Compartment) ECM MAIN)
  • Between the ECM main relay (pin 4 of Fuse and Relay Box (Engine Compartment) ECM MAIN) and the body ground

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

3) Are all of the results normal?

Yes

=>Go to ECM replacement.

No

Repair the circuit or connection as necessary.

=>Go to Repair verification.

7. ECM replacement

Note

  • Perform programming after replacing the ECM.

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM removal".

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM installation".

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM setting".

Procedure completion

=>Go to Repair verification.

8. Repair verification

1) Clear the DTC with a scan tool.

2) Turn OFF the ignition switch for 30 seconds or more.

3) Turn ON the ignition switch.

4) Observe the DTC information with a scan tool.