ECM Power Source Circuit

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

DESCRIPTION

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

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

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

(a) Disconnect the B12 ECM connector.

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

Standard resistance:





(c) Reconnect the ECM connector.

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

2. INSPECT ECM (IGSW VOLTAGE)

(a) Disconnect the A10 ECM connector.





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

Standard voltage:





(c) Reconnect the ECM connector.

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

3. CHECK ENGINE ROOM JUNCTION BLOCK (EFI RELAY VOLTAGE)

(a) Remove the engine room junction block from the engine room R/B.





(b) Turn the engine switch on (IG).

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

Standard voltage:





OK -- INSPECT ENGINE ROOM JUNCTION BLOCK (EFI RELAY)
NG -- Continue to next step.

4. INSPECT EFI MAIN FUSE

(a) Remove the EFI MAIN fuse from the engine room R/B.





(b) Measure the EFI MAIN fuse resistance.

Standard resistance:

Below 1 Ohms

(c) Reinstall the EFI MAIN fuse.

NG -- REPLACE EFI MAIN FUSE

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI RELAY - BATTERY)

5. INSPECT ENGINE ROOM JUNCTION BLOCK (EFI RELAY)

(a) Remove the engine room junction block from the engine room R/B.





(b) Measure the resistance between the terminals.

Standard resistance:





(c) Reinstall the engine room junction block.

NG -- REPLACE ENGINE ROOM JUNCTION BLOCK
OK -- Continue to next step.

6. INSPECT EFI NO. 2 FUSE

(a) Remove the EFI No. 2 fuse from the engine room R/B.





(b) Measure the EFI No. 2 fuse resistance.

Standard resistance:

Below 1 Ohms

(c) Reinstall the EFI No. 2 fuse.

NG -- REPLACE EFI NO. 2 FUSE
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (ECM - EFI RELAY)

(a) Disconnect the A10 ECM connector.

(b) Remove the engine room junction block from the engine room R/B.

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

Standard resistance (Check for open):





Standard resistance (Check for short):





(d) Reinstall the engine room junction block.

(e) Reconnect the ECM connector.

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

8. CHECK HARNESS AND CONNECTOR (EFI RELAY - BODY GROUND)

(a) Remove the engine room junction block from the engine room R/B.

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

Standard resistance (Check for open):





(c) Reinstall the engine room junction block.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

9. INSPECT IG2 RELAY

(a) Remove the IG2 relay from the engine room R/B.





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

Standard resistance:





(c) Reinstall the IG2 relay.

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

10. CHECK HARNESS AND CONNECTOR (IG2 RELAY - BODY GROUND)

(a) Remove the IG2 relay from the engine room R/B.

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

Standard resistance:





(c) Reinstall the IG2 relay.

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

11. CHECK HARNESS AND CONNECTOR (IG2 RELAY - BATTERY)

(a) Remove the IG2 relay from the engine room R/B.

(b) Disconnect the negative battery terminal.

(c) Disconnect the positive battery terminal.

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

Standard resistance (Check for open):





Standard resistance (Check for short):





(e) Reinstall the IG2 relay.

(f) Reconnect the positive battery terminal.

(g) Reconnect the negative battery terminal.

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

12. CHECK HARNESS AND CONNECTOR (IG2 RELAY - ECM)

(a) Remove the IG2 relay from the engine room R/B.

(b) Disconnect the 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):





(d) Reconnect the ECM connector.

(e) Reinstall the IG2 relay.

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

13. CHECK HARNESS AND CONNECTOR (IG2 RELAY - MAIN BODY ECU)

(a) Remove the IG2 relay from the engine room R/B.

(b) Disconnect the main body ECU connector.

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

Standard resistance (Check for open):





Standard resistance (Check for short):





(d) Reconnect the main body ECU connector.

(e) Reinstall the IG2 relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START How To Proceed With Troubleshooting