Component Tests and General Diagnostics

1GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: ECM Power Source Circuit
- ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned ON, the battery voltage is applied to the 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 relay) and supplying power to either terminal +B or +B2 of the ECM.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (BATTERY - INTEGRATION RELAY)





(a) Remove the integration relay from the engine room junction block Testing and Inspection.

(b) Measure the voltage according to the value(s) in the table below.

Standard voltage:





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

2. INSPECT INTEGRATION RELAY (EFI RELAY AND IG2 RELAY)





(a) Remove the integration relay from the engine room relay block Testing and Inspection.

(b) Inspect the EFI NO. 1 fuse and the IG2 MAIN fuse.

(1) Remove the EFI NO. 1 fuse and IG2 MAIN fuse from the integration relay.

(2) Measure the resistance according to the value(s) in the table below.

Standard resistance:





(c) Inspect the EFI relay and the IG2 relay.

(1) Measure the resistance according to the value(s) in the table below.

Standard resistance:





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

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





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

(1) Remove the integration relay from the engine room junction block Testing and Inspection.

(2) Disconnect the A24 ECM connector.

(3) Measure the resistance according to the value(s) in the table below.

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 according to the value(s) in the table below.

Standard resistance (Check for open):





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

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





(a) Disconnect the D74 ECM connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard resistance (Check for open):





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

5. INSPECT ECM (IGSW VOLTAGE)





(a) Disconnect the D74 and A24 ECM connectors.

(b) Measure the voltage according to the value(s) in the table below.

Standard voltage:





NG -- INSPECT FUSE (IGN)

OK -- REPLACE ECM Removal

6. INSPECT FUSE (IGN)





(a) Remove the IGN fuse from the engine room relay block.

(b) Measure the resistance according to the value(s) in the table below.

Standard resistance (Check for open):





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

7. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM, INTEGRATION RELAY - BODY GROUND)





(a) Remove the integration relay from the engine room junction block Testing and Inspection.

(b) Disconnect the A24 ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard resistance (Check for open):





Standard resistance (Check for short):





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

8. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - IGNITION SWITCH ASSEMBLY)





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

(1) Remove the integration relay from the engine room junction block Testing and Inspection.

(2) Disconnect the J9 ignition switch connector.

(3) Measure the resistance according to the value(s) in the table below.

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 according to the value(s) in the table below.

Standard resistance (Check for open):





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

9. INSPECT IGNITION SWITCH ASSEMBLY

(a) Disconnect the J9 ignition switch connector.





(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NG -- REPLACE IGNITION SWITCH ASSEMBLY Removal

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR