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ECM Communication Stop Mode: Procedure

  1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL 
    1. Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and the branch wire.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

      NOTE:

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected. Refer to INITIALIZATION

    NEXT: Go to next step 

  2. CHECK FOR OPEN IN CAN BUS WIRE (ECM MAIN WIRE) 
    1. Turn the ignition switch off.
    2. Disconnect the E77 ECM connector.
      Fig 1: Checking CAN Bus Wire (ECM Main Wire)
      GTY309275Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      E77-32 (CANH) - E77-31 (CANL) Ignition switch off 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to ECM)

    NG → REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CAN-H, CAN-L) 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (ECM - BATTERY AND BODY GROUND) 
    1. Connect the cable to the negative (-) battery terminal.
      NOTE:

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected. Refer to INITIALIZATION .

    2. Disconnect the E77, E78 and B50 ECM connectors.
      Fig 2: ECM Connector Terminal Identification
      GTY309782Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      B50-14 (E01) - Body ground Always Below 1 Ω
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      E77-21 (IGSW) - Body ground Ignition switch ON 11 to 14 V
      E78-22 (+B) - Body ground Ignition switch ON 11 to 14 V
      E78-23 (+B2) - Body ground Ignition switch ON 11 to 14 V
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to ECM)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   4 

  4. REPLACE ECM. Refer to  REMOVAL 
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