ECM Power Source Circuit

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

DESCRIPTION

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

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
* After turning ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work Service Precautions.
* Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

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

(a) Disconnect the ECM connector.

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

Standard Resistance:





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

2. INSPECT ECM (IGSW VOLTAGE)

(a) Disconnect the ECM connector.





(b) Turn the ignition switch to ON.

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

Standard Voltage:





Result





Text in Illustration





B -- INSPECT IG2 RELAY

C -- INSPECT IGNITION SWITCH ASSEMBLY
A -- Continue to next step.

3. INSPECT ECM (MREL VOLTAGE)

(a) Remove the EFI MAIN relay.





(b) Turn the ignition switch to ON.

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

Standard Voltage:





Text in Illustration





NG -- CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY TERMINAL - ECM)
OK -- Continue to next step.

4. INSPECT EFI MAIN RELAY

(a) Inspect the EFI MAIN relay Testing and Inspection.

NG -- REPLACE EFI MAIN RELAY
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY)

(a) Remove the EFI MAIN relay from the engine room relay block.

(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):





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN RELAY - ECM)
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (BATTERY - EFI MAIN RELAY)

(a) Remove the EFI MAIN relay from the engine room relay block.

(b) Disconnect the cable from the negative (-) battery terminal.

(c) Disconnect the cable from 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):





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

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

(a) Remove the EFI MAIN relay 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 -- REPAIR OR REPLACE HARNESS OR CONNECTOR

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

8. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY TERMINAL - ECM)

(a) Disconnect the ECM connector.

(b) Remove the EFI MAIN relay from the engine room relay block.

(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 (EFI MAIN RELAY - ECM)

OK -- REPLACE ECM Removal

9. INSPECT IG2 RELAY

(a) Inspect the IG2 relay Testing and Inspection.

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

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

(a) Remove the IG2 relay from the engine room relay block.

(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):





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

11. CHECK HARNESS AND CONNECTOR (IG2 RELAY POWER SOURCE)

(a) Remove the IG2 relay from the engine room relay block.





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

Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BATTERY)
OK -- Continue to next step.

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

(a) Remove the IG2 relay 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 -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

13. CHECK HARNESS AND CONNECTOR (IG2 RELAY - POWER MANAGEMENT CONTROL ECU)

(a) Disconnect the power management control ECU connector.

(b) Remove the IG2 relay from the engine room relay block.

(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 -- GO TO SMART KEY SYSTEM Problem Symptoms Table

14. INSPECT IGNITION SWITCH ASSEMBLY

(a) Inspect the ignition switch Assembly Testing and Inspection.

NG -- REPLACE IGNITION SWITCH ASSEMBLY Removal
OK -- Continue to next step.

15. CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - ECM)

(a) Disconnect the ignition switch assembly connector.

(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):





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

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