CAN COMMUNICATION SYSTEM(w/ Toyota Safety Sense) ABS and Traction Actuator (Skid Control ECU) Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
ABS and Traction Actuator (Skid Control ECU) Communication Stop Mode

Either condition is met:


  • Communication stop for "Skid Control (ABS/VSC/TRC)" is indicated on the "Communication Bus Check" screen of the GTS.

    Click here

  • Communication system DTCs (DTCs that start with U) that correspond to "ABS and Traction Actuator (Skid Control ECU) Communication Stop Mode" in "DTC Combination Table" are output.

    Click here


  • Power source or inside skid control ECU (brake actuator assembly)

  • Skid control ECU (brake actuator assembly) branch wire or connector

  • Skid control ECU (brake actuator assembly)

WIRING DIAGRAM

B004755E05

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 OPEN IN CAN BUS WIRE (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) BRANCH WIRE)


    1. B00470AE01
      Text in Illustration
      *A for LHD with CVT and RHD
      *B except LHD with CVT
      *a

      Front view of wire harness connector

      (to skid control ECU (brake actuator assembly))

      Disconnect the skid control ECU (brake actuator assembly) connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition

      A78-23 (CANH) - A78-21 (CANL)*1

      A79-23 (CANH) - A79-21 (CANL)*2

      		 Ignition switch off 54 to 69 Ω

      *1: for LHD with CVT and RHD

      *2: except LHD with CVT


    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) BRANCH WIRE)

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

    B0046AME01
    Text in Illustration
    *A for LHD with CVT and RHD
    *B except LHD with CVT
    *a

    Front view of wire harness connector

    (to skid control ECU (brake actuator assembly))

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition

      A78-1 (+BS) - Body ground*1

      A79-1 (+BS) - Body ground*2

      		 Always 11 to 14 V

      A78-14 (+BM) - Body ground*1

      A79-14 (+BM) - Body ground*2

      		 Always 11 to 14 V

      A78-20 (IG1) - Body ground*1

      A78-20 (IG1) - Body ground*2

      		 Ignition switch ON 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition

      A78-13 (GND1) - Body ground*1

      A79-13 (GND1) - Body ground*2

      		 Always Below 1 Ω

      A78-26 (GND2) - Body ground*1

      A79-26 (GND2) - Body ground*2

      		 Always Below 1 Ω

      *1: for LHD with CVT and RHD

      *2: except LHD with CVT

      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG (w/o Stop and Start System) C
      NG (except IG1 circuit) (w/ Stop and Start System)
      NG (for IG1 circuit) (w/ Stop and Start System) D

    A

    REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) Click here

    B

    REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    D

    GO TO STOP AND START SYSTEM (FOR BACKUP BOOST CONVERTER CIRCUIT) Click here