Component Tests and General Diagnostics

1NZ-FXE ENGINE CONTROL SYSTEM: SFI SYSTEM: ECM Power Source Circuit

ECM Power Source Circuit

DESCRIPTION

The power source circuit of the hybrid system differs from the conventional power source circuit in the method in which the battery voltage is supplied to IGSW terminal of the ECM. The hybrid system has adopted one relay to serve as the power switch, which is controlled by the power source control ECU.
When the HV system is turned ON, the power source control ECU actuates the IG2 relay, which applies the battery voltage to IGSW terminal of the ECM. This causes the MREL terminal to transmit a signal to the EFI M relay. Then, the current that passes through the contact points of the EFI M relay (which is actuated by the MREL signal) flows to the +B terminal of the ECM.
When the power switch is turned OFF, the ECM keeps the EFI M relay ON for a maximum of 2 seconds, in order to initialize the throttle valve.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK ECM (+B VOLTAGE)




(a) Turn the power switch ON (IG).
(b) Measure the voltage between the specified terminals of the E5 and E7 ECM connectors.
Standard voltage:






OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS TABLE
NG -- Continue to next step.

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




(a) Disconnect the E5 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
OK -- Continue to next step.

3. CHECK ECM (IGSW VOLTAGE)




(a) Turn the power switch ON (IG).
(b) Measure the voltage between the specified terminals of the E5 and E6 ECM connectors.
Standard voltage:






OK -- CHECK ECM (MREL VOLTAGE)
NG -- Continue to next step.

4. INSPECT FUSE (IGN FUSE)




(a) Remove the IGN fuse from the driver side junction block.
(b) Measure the resistance of the IGN fuse.
Standard resistance:
Below 1 Ohms
(c) Reinstall the IGN fuse.
NG -- CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE
OK -- Continue to next step.

5. INSPECT INTEGRATION RELAY (IG2 RELAY)




(a) Remove the integration relay from the engine room relay block.
(b) Inspect the IG2 relay.
Standard resistance:





(c) Reinstall the integration relay.
NG -- REPLACE INTEGRATION RELAY
OK -- Continue to next step.

6. INSPECT FUSE (AM2 FUSE)




(a) Remove the AM2 fuse from the engine room relay block.
(b) Measure the resistance of the AM2 fuse.
Standard resistance:
Below 1 Ohms
(c) Reinstall the AM2 fuse.
NG -- CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE
OK -- CHECK AND REPAIR HARNESS AND CONNECTOR (BATTERY - IG2 RELAY, IG2 RELAY - ECM)
7. CHECK ECM (MREL VOLTAGE)




(a) Turn the power switch ON (IG).
(b) Measure the voltage between the specified terminals of the E5 and E7 ECM connectors.
Standard voltage:






NG -- REPLACE ECM
OK -- Continue to next step.

8. INSPECT FUSE (EFI FUSE)




(a) Remove the EFI fuse from the engine room relay block.
(b) Measure the resistance of the EFI fuse.
Standard resistance:
Below 1 Ohms
(c) Reinstall the EFI fuse.
NG -- CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE
OK -- Continue to next step.

9. INSPECT INTEGRATION RELAY (EFI M RELAY)




(a) Remove the integration relay from the engine room relay block.
(b) Inspect the EFI M relay.
Standard resistance:





(c) Reinstall the integration relay.
NG -- REPLACE INTEGRATION RELAY
OK -- Continue to next step.

10. CHECK HARNESS AND CONNECTOR (EFI M RELAY - ECM, EFI M RELAY - BODY GROUND)
(a) Check the harness and connectors between the EFI M relay and ECM connector.





(1) Remove the integration relay from the engine room relay block.





(2) Disconnect the E7 ECM connector.
(3) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):






(4) Reinstall the integration relay.
(5) Reconnect the ECM connector.
(b) Check the harness and the connectors between the EFI M relay and the body ground.
(1) Remove the integration relay from the engine room relay block.
(2) Measure the resistance between the wire harness side connector and body ground.
Standard resistance (Check for open):






(3) Reinstall the integration relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK AND REPAIR HARNESS AND CONNECTOR (TERMINAL +B OF ECM - BATTERY POSITIVE TERMINAL)