Component Tests and General Diagnostics

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 of the ECM.

If the engine switch is turned off, the ECM holds the EFI relay ON for a maximum of 2 seconds to allow for the initial setting of the throttle valve.

When the engine switch is turned on (IG), voltage from the ECM's MREL terminal applies to the engine room junction block (EFI relay). This causes the contacts of the engine room junction block (EFI relay) to close, which supplies power to terminal +B or +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