Component Tests and General Diagnostics

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

DESCRIPTION

When the ignition 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 ignition 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.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. INSPECT ECM (+B VOLTAGE)

(a) Turn the ignition switch on (IG).

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

Standard voltage:

Text in Illustration

NG -- CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

2. 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:

Check for open

(c) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND)
OK -- Continue to next step.

3. INSPECT ECM (MREL VOLTAGE)

(a) Turn the ignition switch on (IG).

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

Standard voltage:

Text in Illustration

NG -- INSPECT ECM (IGSW VOLTAGE)
OK -- Continue to next step.

4. CHECK FUSE (EFI MAIN AND EFI NO. 2 FUSE)

(a) Remove the EFI MAIN and EFI No. 2 fuse from the engine room relay block.

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

Standard resistance:

Text in Illustration

(c) Reinstall the fuses.

NG -- REPLACE FUSE (EFI MAIN OR EFI NO. 2 FUSE)
OK -- Continue to next step.

5. INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (EFI RELAY)

(a) Inspect the EFI relay Testing and Inspection.

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

6. CHECK HARNESS AND CONNECTOR (EFI RELAY - ECM, EFI RELAY - BODY GROUND)

(a) Remove the engine room junction block 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
Check for short

(d) Reinstall the engine room junction block.

(e) Reconnect the ECM connector.

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

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

(a) Remove the engine room junction block 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
Check for short

(d) Reinstall the engine room junction block assembly.

(e) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI RELAY - ECM)

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI RELAY - EFI MAIN FUSE)

8. INSPECT ECM (IGSW VOLTAGE)

(a) Turn the ignition switch on (IG).

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

Standard voltage:

Text in Illustration

NG -- CHECK HARNESS AND CONNECTOR (ECM - IG2 RELAY)

OK -- REPLACE ECM Components

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

(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:

(d) Reconnect the ECM connector.

(e) Reinstall the IG2 relay.

NG -- CHECK FUSE (IG2 FUSE)
OK -- Continue to next step.

10. INSPECT IG2 RELAY

(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:

(c) Reinstall the IG2 relay.

NG -- REPLACE IG2 RELAY
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) Turn the ignition switch on (IG)

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

Standard voltage:

Text in Illustration

(d) Reinstall the IG2 relay.

NG -- CHECK FUSE (IGN FUSE)
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:

Text in Illustration

C -- CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - MAIN BODY ECU)

B -- CHECK HARNESS AND CONNECTOR (IGNITION SWITCH - IG2 RELAY)

A -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BODY GROUND)

13. CHECK FUSE (IG2 FUSE)

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

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

Standard resistance:

Text in Illustration

(c) Reinstall the IG2 fuse

NG -- REPLACE FUSE (IG2 FUSE)

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BATTERY)

14. CHECK FUSE (IGN FUSE)

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

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

Standard resistance:

Text in Illustration

(c) Reinstall the IGN fuse.

NG -- REPLACE FUSE (IGN FUSE)

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - ECM)

15. CHECK HARNESS AND CONNECTOR (IGNITION SWITCH - IG2 RELAY)

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

(b) Disconnect the ignition switch connector.

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

Standard resistance:

Check for open
Check for short

(d) Reinstall the IG2 relay.

(e) Reconnect the ignition switch connector.

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

16. INSPECT IGNITION SWITCH

(a) Inspect the ignition switch assembly Ignition Switch.

NG -- REPLACE IGNITION SWITCH Components

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

17. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - MAIN BODY ECU)

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

(b) Remove the instrument panel junction block (main body ECU).

(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 IG2 relay.

(e) Reconnect the main body ECU connector.

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

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR