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DTC C1242/42 IG2 Power Source Circuit: Wiring Diagram

Fig 1: IG2 Power Source Circuit Wiring Diagram
G04063878Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. INSPECT FUSE (IGN) 
    1. Remove the IGN fuse from the cowl side junction block RH.
    2. Measure the resistance of the fuse.

    Standard resistance: Below 1 Ω 

    NG : REPLACE FUSE 

    OK : Go To Next Step 

  2. INSPECT BATTERY 
    1. Check the battery voltage.

    Standard voltage: 11 to 14 V 

    Result 

    RESULT REFERENCE

    Result Proceed to
    Battery voltage is OK (when using intelligent tester) A
    Battery voltage is OK (when not using intelligent tester) B
    Battery voltage is abnormal C

    B : Go to step  4

    C : RECHARGE OR REPLACE BATTERY 

    A : Go To Next Step 

  3. DATA LIST (IG VOLTAGE) 
    1. Check the DATA LIST for proper function of the IG voltage.

    Skid control ECU assembly 

    DATA REFERENCE CHART

    Item Measurement Item / Range (Display) Normal Condition Diagnostic Note
    IG VOLTAGE ECU IG power voltage / UNDER or NORMAL or OVER - -

    OK : Display is NORMAL 

    OK : REPLACE SKID CONTROL ECU ASSEMBLY 

    NG : Go To Next Step 

  4. CHECK WIRE HARNESS (SKID CONTROL ECU ASSEMBLY - BATTERY AND BODY GROUND) 
    1. Measure the voltage of the wire harness side connectors.

      Standard voltage 

      Fig 2: Identifying Wire Harness Skid Control ECU Assembly Connector Terminals
      G04063879Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TESTER CONNECTION AND SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      A40-6 (IG1) - A40-17 (GND4) Ignition switch ON 10 to 14 V
      A40-6 (IG1) - A40-8 (GND3) Ignition switch ON 10 to 14 V
      A40-6 (IG1) - A39-6 (GND2) Ignition switch ON 10 to 14 V
      A40-6 (IG1) - A39-31 (GND1) Ignition switch ON 10 to 14 V
      A40-6 (IG1) - Body ground Ignition switch ON 10 to 14 V
    2. Measure the resistance of the wire harness side connectors.

    Standard resistance 

    TESTER CONNECTION AND SPECIFIED CONDITION CHART

    Tester Connection Condition Specified Condition
    A40-17 (GND4) - Body ground Always Below 1 Ω
    A40-8 (GND3) - Body ground Always Below 1 Ω
    A39-6 (GND2) - Body ground Always Below 1 Ω
    A39-31 (GND1) - Body ground Always Below 1 Ω

    NG : REPAIR OR REPLACE HARNESS AND CONNECTOR 

    OK : REPLACE SKID CONTROL ECU ASSEMBLY