ECM Power Source Circuit

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

DESCRIPTION

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

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
* Inspect the fuses for circuits related to this system before performing the following inspection procedure.
* 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.

PROCEDURE

1. INSPECT INTEGRATION RELAY (POWER SOURCE VOLTAGE)





(a) Remove the integration relay.

(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 (INTEGRATION RELAY - BATTERY)
OK -- Continue to next step.

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





(a) Remove the integration relay.

(b) Inspect the relay

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

Standard Resistance:





Text in Illustration





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

3. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM)

(a) Remove the integration relay.

(b) Disconnect the ECM connector.

(c) 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.

4. 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.

5. INSPECT ECM (IGSW TERMINAL VOLTAGE)





(a) Disconnect the ECM connectors.

(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 -- REPLACE ECM Removal
A -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (ECM - INTEGRATION RELAY)

(a) Remove the integration relay.

(b) Disconnect the ECM connector.

(c) 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.

7. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - IGNITION SWITCH - BODY GROUND)

(a) Remove the integration relay.

(b) Disconnect the ignition switch assembly connector.

(c) 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.

8. INSPECT IGNITION SWITCH ASSEMBLY





(a) Remove the ignition switch assembly.

Text in Illustration





(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 (IGNITION SWITCH - BATTERY)