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Power Steering ECU Communication Stop Mode: Procedure

  1. CHECK CAN BUS WIRE FOR DISCONNECTION (POWER STEERING ECU BRANCH WIRE) 
    1. Turn the power switch off.
    2. Disconnect the power steering ECU connector.
      Fig 1: Identifying Power Steering ECU Connector Terminals
      GTY231114Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front view of wire harness connector
      (to Power Steering ECU)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      L54-1 (CANH) - L54-7 (CANL) Power switch off 54 to 69 Ω

    NG → REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (POWER STEERING ECU BRANCH WIRE) 

    OK: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL) 
    1. Turn the power switch on (IG).
    2. Measure the voltage according to the value(s) in the table below.
      Fig 2: Identifying Power Steering ECU Connector Terminals
      GTY229094Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      L54-6 (IG) - Body ground Power switch on (IG) 11 to 14 V
      Callouts For Fig. 66

      *1 Front view of wire harness connector
      (to Power Steering ECU)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (GROUND TERMINAL) 
    1. Turn the power switch off.
    2. Disconnect the power steering ECU connector.
      Fig 3: Identifying Power Steering ECU Connector Terminals
      GTY213701Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Front view of wire harness connector
      (to Power Steering ECU)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A27-2 (PGND) - Body ground Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT) 

    OK → See step   4 

  4. REPLACE POWER STEERING ECU. Refer to  REMOVAL