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Home >> Toyota >> 2018 >> Corolla LE >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Communication Devices >> Can Communication System - (W/O Central Gateway Ecu) - Diagnostics & Circuit Tests (2 Of 2) (Model Code: ZRE172) >> CAN COMMUNICATION SYSTEM (W/O Central Gateway ECU) >> Main Body ECU Communication Stop Mode [08/2013 - ] >> Procedure
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Main Body ECU Communication Stop Mode [08/2013 - ]: Procedure

  1. CHECK FOR OPEN IN CAN BUS LINES (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) BRANCH LINE) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the E31 main body ECU (multiplex network body ECU) connector.
      GTY429248Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Main Body ECU (Multiplex Network Body ECU))
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      E31-14 (CANH) - E31-13 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω

    Result: 

    NG 

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) 

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 
    1. Disconnect the 3C and 3D driver side junction block assembly connectors.
    2. Measure the resistance according to the value(s) in the table below.
      GTY476242Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Driver Side Junction Block Assembly)

      Standard Resistance

      Tester Connection Condition Specified Condition
      3C-9 (GND1) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω
      3D-12 (GND1) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω
    3. Disconnect the 3A driver side junction block assembly connector.
    4. Reconnect the cable to the negative (-) battery terminal.
    5. Measure the voltage according to the value(s) in the table below.
      GTY428934Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Driver Side Junction Block Assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      3A-24 (BECU) - Body ground Always 11 to 14 V

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) 

    Result: 

    OK 

    See step  3

  3. INSPECT DRIVER SIDE JUNCTION BLOCK ASSEMBLY (IG1 NO. 1 RELAY AND ACC RELAY) 
    1. Inspect the IG1 No. 1 relay and ACC relay of the driver side junction block assembly.

      HINT: 

      If the IG signal circuit and ACC signal circuit have no problem, replace the main body ECU (multiplex network body ECU).

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [08/2013 - ] 

    Result: 

    NG 

    REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [08/2013 - ] 

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