CAN COMMUNICATION SYSTEM(w/o Toyota Safety Sense) Driving Support ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area

Driving Support ECU

Communication Stop Mode

Either condition is met:


  • "DSS1" is not displayed on "Bus Check"

  • "Driving Support ECU Communication Stop Mode" in "DTC Communication Table" applies.

  • Power source or inside driving support ECU

  • Driving support ECU branch wire or connector

  • Driving support ECU

WIRING DIAGRAM

A01VJ5HE10
*a No. 2 Junction Connector
*b from IG1 NO. 1 Relay
*c ECU-IG NO. 2
*d Driving Support ECU

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 is 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 OPEN IN CAN BUS WIRE (DRIVING SUPPORT ECU BRANCH WIRE)


    1. Disconnect the F121 driving support ECU connector.

    2. A01VFGHE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Driving Support ECU)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F121-39 (CA2H) - F121-17 (CA2L) Ignition switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (DRIVING SUPPORT ECU BRANCH WIRE)

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. A01VIYXE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Driving Support ECU)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F121-30 (B) - Body ground Ignition switch ON 11 to 14 V

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F121-25 (GND) - Body ground Always Below 1Ω
      Result
      Result Proceed to
      NG A
      OK (for LHD) B
      OK (for RHD) C

    A

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    B

    REPLACE DRIVING SUPPORT ECU Click here

    C

    REPLACE DRIVING SUPPORT ECU Click here