CAN COMMUNICATION SYSTEM(w/o Toyota Safety Sense) Main Body ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Main Body ECU Communication Stop Mode

Either condition is met:


  • "Main Body" is not displayed on "Bus Check".

  • "Main Body ECU Communication Stop Mode" in "DTC Combination Table" applies.

  • Power source or inside main body ECU (multiplex network body ECU)

  • Main body ECU (multiplex network body ECU) branch wire or connector

  • Main body ECU (multiplex network body ECU)

WIRING DIAGRAM

A01VLT9E02

CAUTION / NOTICE / HINT

Note


  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

  • Turn the ignition switch off before measuring the resistances between CAN bus main wires and between CAN bus branch wires.

  • Turn the ignition switch off before inspecting CAN bus wires for a ground short.

  • After the ignition switch is turned off, check that the key reminder warning system are not operating.

  • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

Tech Tips


  • Operating the ignition switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE


  1. CHECK FOR OPEN IN CAN BUS WIRE (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) BRANCH WIRE)

    A01VFUGE02
    Text in Illustration
    *a

    Front view of wire harness connector

    (to Main Body ECU (Multiplex Network Body ECU))

    1. Disconnect the F76 main body ECU (multiplex network body ECU) connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F76-14 (CANH) - F76-13 (CANL) Ignition switch off 54 to 69 Ω

    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. Remove the main body ECU (multiplex network body ECU) Click here.

      A01VI2OE01
      Text in Illustration
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 - -

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      MB-11 (GND1) - Body ground Always Below 1 Ω

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      MB-30 (BECU) - Body ground Always 11 to 14 V
      MB-32 (IG) - Body ground Ignition switch ON 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  3. CHECK INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    A01VLRDE01
    Text in Illustration
    *a

    Component without harness connected

    (Instrument Panel Junction Block Assembly)

    		 - -

    1. Disconnect the 3A, 3B and 3C instrument panel junction block assembly connectors.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      MB-11 (GND1) - 3B-8 Always Below 1 Ω
      MB-30 (BECU) - 3C-21 Always Below 1 Ω
      MB-32 (IG) - 3A-40 Always Below 1 Ω
      MB-11 (GND1) or 3B-8 - Body ground Always 10 kΩ or higher
      MB-30 (BECU) or 3C-21 - Body ground Always 10 kΩ or higher
      MB-32 (IG) or 3A-40 - Body ground Always 10 kΩ or higher

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here