GSIC - Global Service Information Center

### ECD SYSTEM > ECM Power Source Circuit

## for Preparation Click here

## DESCRIPTION

When the ignition switch is turned ON, 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 MAIN relay and supplying power to terminal +B of the ECM.

## WIRING DIAGRAM

## INSPECTION PROCEDURE

NOTICE:

  If the ECM is replaced, the new ECM needs initialization (Click here).

1.CHECK ECM TERMINAL VOLTAGE (+B TERMINAL)

1. Turn the ignition switch ON.

1. Measure the voltage of the ECM connectors.

   Standard voltage:

     Tester Connection | Specified Condition
     E5-1 (+B) - E7-7 (E1) | 9 to 14 V

| OK |

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS TABLE

NG |

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

1. Disconnect the E7 ECM connector.

1. Measure the resistance of the wire harness side connector.

   Standard resistance:

     Tester Connection | Specified Condition
     E7-7 (E1) - Body ground | Below 1 Ω

| NG |

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK |

3.CHECK ECM TERMINAL VOLTAGE (IGSW TERMINAL)

1. Turn the ignition switch ON.

1. Measure the voltage of the ECM connectors.

   Standard voltage:

     Tester Connection | Specified Condition
     E5-9 (IGSW) - E7-7 (E1) | 9 to 14 V

| OK |

Go to step 6

NG |

4.INSPECT FUSE (IGN FUSE)

1. Remove the IGN fuse from the instrument panel J/B.

1. Measure the resistance of the fuse.

   Standard resistance:
     Below 1 Ω

| NG |

CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE

OK |

5.INSPECT IGNITION SWITCH ASSEMBLY

1. Disconnect the I9 ignition switch connector.

1. Measure the resistance of the ignition switch.

   Standard resistance:

     Tester Connection | Switch Condition | Specified Condition
     5 (AM2) - 6 (IG2) | LOCK | 10 kΩ or higher
     5 (AM2) - 6 (IG2) | ON | Below 1 Ω

| NG |

REPLACE IGNITION SWITCH ASSEMBLY

OK |

6.CHECK ECM TERMINAL VOLTAGE (MREL TERMINAL)

1. Turn the ignition switch ON.

1. Measure the voltage of the ECM connectors.

   Standard voltage:

     Tester Connection | Specified Condition
     E5-8 (MREL) - E7-7 (E1) | 9 to 14 V

| NG |

REPLACE ECM

OK |

7.INSPECT FUSE (EFI FUSE)

1. Remove the EFI fuse from the engine room J/B.

1. Measure the resistance of the fuse.

   Standard resistance:
     Below 1 Ω

| NG |

CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE

OK |

8.INSPECT INTEGRATION RELAY (MAIN RELAY)

1. Remove the integration relay from the engine room J/B (Click here).

1. Disconnect the 1J integration relay connector.

1. Measure the voltage of the MAIN relay.

   Standard voltage:

     Tester Connection | Condition | Specified Condition
     1J-4 - Body ground | Ignition switch ON | 10 to 14 V

| NG |

REPLACE ECM

OK |

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

1. Disconnect the 1J integration relay connector from the engine room J/B (Click here).

1. Disconnect the E5 ECM connector.

1. Measure the resistance of the wire harness side connectors.

   Standard resistance:

     Tester Connection | Specified Condition
     1J-4 - E5-1 (+B) | Below 1 Ω
     1J-4 or E5-1 (+B) - Body ground | 10 kΩ or higher

| NG |

REPAIR OR REPLACE HARNESS AND CONNECTOR (MAIN RELAY - ECM)

OK |

REPAIR OR REPLACE HARNESS AND CONNECTOR (+B TERMINAL OF ECM - BATTERY POSITIVE TERMINAL)