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Home >> Toyota >> 2008 >> Tacoma Base, 2D Pickup, 4WD >> Repair and Diagnosis >> Engine Performance >> Engine Control System (2TR-FE) >> SFI System >> ECM Power Source Circuit >> Inspection Procedure
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Inspection Procedure

  1. INSPECT ECM (+B VOLTAGE) 
    1. Turn the ignition switch to ON.
    2. Measure the voltage between the terminals of the ECM connectors.

      Standard Voltage 

      VOLTAGE SPECIFICATION

      Tester Connections Specified Conditions
      +B (E8-1) - E1 (E4-3) 9 to 14 V
      Fig 1: Identifying E4 And E8 ECM Connector
      G05198368Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

    NG: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the negative battery cable.
    2. Disconnect the E4 ECM connector.
      3. Fig 2: Identifying E4 ECM Connector
      G05677306Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check the resistance.

      Standard Resistance 

      RESISTANCE SPECIFICATION

      Tester Connections Specified Conditions
      E1 (E4-3) - Body ground Below 1 Ω
    4. Reconnect the ECM connector.
    5. Reconnect the negative battery cable.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  3. INSPECT ECM (IGSW VOLTAGE) 
    1. Turn the ignition switch to ON.
    2. Measure the voltage between the terminals of the ECM connectors.

      Standard Voltage 

      VOLTAGE SPECIFICATION

      Tester Connections Specified Conditions
      IGSW (E8-9) - E1 (E4-3) 9 to 14 V
      Fig 3: Identifying E4 And E8 ECM Connector
      G05198370Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK:  Go to step  6

    NG: Go to next step 

  4. CHECK FUSE (AM2 AND IGN) 
    1. Check the AM2 fuse.
      1. Remove the AM2 fuse from the engine room R/B.
      2. Check the AM2 fuse resistance.

        Standard Resistance: Below 1 Ω 

      3. Reinstall the AM2 fuse.
        4. Fig 4: Identifying AM2 Fuse And IGN Fuse
        G05677308Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check the IGN fuse.
      1. Remove the IGN fuse from the driver side J/B.
      2. Check the IGN fuse resistance.

        Standard Resistance: Below 1 Ω 

      3. Reinstall the IGN fuse.

    NG: CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE 

    OK: Go to next step 

  5. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY 
    1. Disconnect the I7 ignition switch connector.
      2. Fig 5: Identifying I7 Ignition Switch Connector
      G05198237Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check the resistance.

      Standard Resistance 

      RESISTANCE SPECIFICATION

      Ignition Switch Positions Tester Connections Specified Conditions
      LOCK All Terminals 10 kΩ or higher
      ACC 2 - 4 Below 1 Ω
      ON 1 - 4, 2 - 4, 5 - 6 Below 1 Ω
      START 1 - 4, 3 - 4, 5 - 6, 5 - 7 Below 1 Ω
    3. Reconnect the ignition switch connector.

    NG: REPLACE IGNITION OR STARTER SWITCH ASSEMBLY 

    OK: CHECK AND REPAIR HARNESS AND CONNECTOR (BATTERY - IGNITION SWITCH, IGNITION SWITCH - ECM) 

  6. INSPECT ECM (MREL VOLTAGE) 
    1. Turn the ignition switch to ON.
    2. Measure the voltage between the terminals of the ECM connectors.

      Standard Voltage 

      VOLTAGE SPECIFICATION

      Tester Connections Specified Conditions
      MREL (E8-8) - E1 (E4-3) 9 to 14 V
      Fig 6: Identifying E4 And E8 ECM Connector
      G05198373Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE ECM 

    OK: Go to next step 

  7. CHECK FUSE (EFI) 
    1. Remove the EFI fuse from the engine room R/B.
    2. Check the EFI fuse resistance.

      Standard Resistance: Below 1 Ω 

    3. Reinstall the EFI fuse.

    NG: CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE 

    Fig 7: Identifying EFI Fuse
    G05198228Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step 

  8. INSPECT EFI RELAY 
    1. Remove the EFI relay from the engine room R/B.
    2. Check the EFI relay resistance.

      Standard Resistance 

      RESISTANCE SPECIFICATION

      Tester Connections Specified Conditions
      3 - 5 10 kΩ or higher
      3 - 5 Below 1 Ω
      (when battery voltage applied to terminals 1 and 2)
    3. Reinstall the EFI relay.
      4. Fig 8: Identifying EFI Relay Terminals
      G05198087Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE EFI RELAY 

    OK: Go to next step 

  9. CHECK HARNESS AND CONNECTOR (EFI RELAY - ECM, EFI RELAY - BODY GROUND) 
    1. Check the harness and connector between the EFI relay and ECM.
      1. Remove the EFI relay from the engine room R/B.
      2. Disconnect the E8 ECM connector.
      3. Check the resistance.

        Standard Resistance (Check for open) 

        RESISTANCE SPECIFICATION

        Tester Connections Specified Conditions
        Engine room R/B (EFI relay terminal 1) - MREL (E8-8) Below 1 Ω
        Engine room R/B (EFI relay terminal 3) - +B (E8-1) Below 1 Ω

        Standard Resistance (Check for short) 

        RESISTANCE SPECIFICATION

        Tester Connections Specified Conditions
        Engine room R/B (EFI relay terminal 1) or MREL (E8-8) - Body ground 10 kΩ or higher
        Engine room R/B (EFI relay terminal 3) or +B (E8-1) - Body ground 10 kΩ or higher
      4. Reconnect the ECM connector.
      5. Reinstall the EFI relay.
        Fig 9: Identifying EFI Relay And ECM Connector
        G05677313Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check the harness and connector between the EFI relay and body ground.
      1. Remove the EFI relay from the engine room R/B.
      2. Check the resistance.

        Standard Resistance (Check for open): 

        RESISTANCE SPECIFICATION

        Tester Connections Specified Conditions
        Engine room R/B (EFI relay terminal 2) - Body ground Below 1 Ω
      3. Reinstall the EFI relay.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: CHECK AND REPLACE HARNESS AND CONNECTOR (TERMINAL 5 OF EFI RELAY - BATTERY POSITIVE TERMINAL) 

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