CAN COMMUNICATION SYSTEM(w/o Toyota Safety Sense) Brake Actuator (Skid Control ECU) Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Brake Actuator (Skid Control ECU) Communication Stop Mode

Either condition is met:


  • "Skid Control (ABS/VSC/TRAC)" is not displayed on "Bus Check".

  • "Brake Actuator (Skid Control ECU) Communication Stop Mode" in "DTC Combination Table" applies.


  • 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

A01VF81E04
A01VF81E05

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. SYSTEM CHECK


    1. Check the vehicle specifications.

      Result
      Result Proceed to
      for TMC Made A
      for TMMF Made B

    B
    A
  2. CHECK FOR OPEN IN CAN BUS WIRE (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) BRANCH WIRE)


    1. A01VJ9OE02
      Text in Illustration
      *A except LHD with CVT
      *B for LHD with CVT
      *a

      Front view of wire harness connector

      (to skid control ECU (brake actuator assembly))

      Disconnect the A54*1 or A56*2 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

      A54-25 (CANH) - A54-14 (CANL)*1

      A56-25 (CANH) - A56-14 (CANL)*2

      Ignition switch off 54 to 69 Ω

      *1 : except LHD with CVT

      *2 : for LHD with CVT


    NG
    OK
  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

    A01VKPSE01
    Text in Illustration
    *A except LHD with CVT
    *B for 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

      A54-12 (+BS) - Body ground*1

      A56-12 (+BS) - Body ground*2

      Always 11 to 14 V

      A54-24 (BM) - Body ground*1

      A56-24 (BM) - Body ground*2

      Always 11 to 14 V

      A54-34 (IG1) - Body ground*1

      A56-34 (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

      A54-1 (GND1) - Body ground*1

      A56-1 (GND1) - Body ground*2

      Always Below 1 Ω

      A54-13 (GND2) - Body ground*1

      A56-13 (GND2) - Body ground*2

      Always Below 1 Ω

      *1 : except LHD with CVT

      *2 : for LHD with CVT

      Result
      Result Proceed to
      NG A
      OK (for LHD) B
      OK (for RHD) C

    A
    B
    C
  4. CHECK FOR OPEN IN CAN BUS WIRE (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) BRANCH WIRE)


    1. A01VDLGE01
      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 A78*1 or A79*2 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
    OK
  5. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

    A01VKA6E01
    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

      A79-20 (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
      NG A
      OK (for LHD) B
      OK (for RHD) C

    A
    B
    C