ECM Power Source Circuit

2GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: ECM Power Source Circuit
- ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, the battery voltage is applied to terminal IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contacts of the integration relay (EFI MAIN relay) and supplying power to both terminal +B and +B2 of the ECM.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT INTEGRATION RELAY (INTEGRATION RELAY - BODY GROUND)

(a) Remove the integration relay from the engine room No. 1 relay block.





(b) Measure the voltage between the terminal of the integration relay and body ground.

Standard voltage:





(c) Reinstall the integration relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY - BATTERY)
OK -- Continue to next step.

2. INSPECT INTEGRATION RELAY (EFI MAIN RELAY)

(a) Inspect the integration relay Integration Relay.

NG -- REPLACE INTEGRATION RELAY
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (+B, +B2 AND MREL CIRCUIT)

(a) Check the harness and connectors between the integration relay and ECM.





(1) Remove the integration relay from the engine room No. 1 relay block.

(2) Disconnect the A9 ECM connector.

(3) Measure the resistance between the wire harness side connectors.

Standard resistance (Check for open):





Standard resistance (Check for short):





(b) Check the harness and connectors between the integration relay and body ground.

(1) Measure the resistance between the wire harness side connector and body ground.

Standard resistance (Check for open):





(c) Reinstall the integration relay.

(d) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

(a) Disconnect the B30 ECM connector.





(b) Measure the resistance.

Standard resistance (Check for open):





(c) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. INSPECT ECM (IGSW VOLTAGE)

(a) Disconnect the B30 and A9 ECM connectors.





(b) Turn the ignition switch to ON.

(c) Measure the voltage between the terminals of the B30 and A9 ECM connectors.

Standard voltage:





(d) Reconnect the ECM connectors.

OK -- REPLACE ECM
NG -- Continue to next step.

6. INSPECT FUSE (IGN AND IG2 FUSE)

(a) Remove the IGN fuse from the main body ECU (instrument panel junction block).





(b) Remove the IG2 fuse from the engine room No. 1 relay block.





(c) Measure the IGN and IG2 fuse resistance.

Standard resistance:

Below 1 Ohms

(d) Reinstall the IGN fuse.

(e) Reinstall the IG2 fuse.

NG -- CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE
OK -- Continue to next step.

7. INSPECT IG2 RELAY





(a) Remove the IG2 relay from the engine room No. 1 relay block.

(b) Measure the resistance.

Standard resistance:





(c) Reinstall the relay.

NG -- REPLACE IG2 RELAY
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (ECM - ENGINE ROOM NO. 1 RELAY BLOCK)





(a) Remove the IG2 relay from the engine room No. 1 relay block.

(b) Disconnect the A9 ECM connector.

(c) Measure the resistance between the wire harness side connectors.

Standard resistance (Check for open):





Standard resistance (Check for short):





(d) Reinstall the IG2 relay.

(e) Reconnect the ECM connector.

Result:





B -- CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK - MAIN BODY ECU)

C -- CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK - IGNITION SWITCH)

A -- REPAIR OR REPLACE HARNESS OR CONNECTOR

9. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK - MAIN BODY ECU)





(a) Remove the IG2 relay from the engine room No. 1 relay block.

(b) Disconnect the E16 instrument panel junction block (main body ECU) connector.

(c) Measure the resistance between the wire harness side connectors.

Standard resistance (Check for open):





Standard resistance (Check for short):





(d) Reinstall the IG2 relay.

(e) Reconnect the instrument panel junction block (main body ECU) connector.

OK -- CHECK SMART KEY SYSTEM How To Proceed With Troubleshooting

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

10. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK - IGNITION SWITCH)





(a) Remove the IG2 relay from the engine room No. 1 relay block.

(b) Disconnect the E3 ignition switch connector.

(c) Measure the resistance between the wire harness side connectors.

Standard resistance (Check for open):





Standard resistance (Check for short):





(d) Reinstall the IG2 relay.

(e) Reconnect the ignition switch connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

11. INSPECT IGNITION SWITCH ASSEMBLY

(a) Inspect the ignition switch Testing and Inspection.

NG -- REPLACE IGNITION SWITCH ASSEMBLY Removal

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH - BATTERY)