CAN COMMUNICATION SYSTEM Skid Control ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Skid Control ECU Communication Stop Mode

Any of the following conditions are met:


  • Communication stop for "Skid Control (ABS/VSC/TRAC)" is indicated on "Communication Bus Check".

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

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  • Brake booster with master cylinder assembly (skid control ECU) CAN branch wire or connector

  • Power source circuit of brake booster with master cylinder assembly (skid control ECU)

  • Brake booster with master cylinder assembly (skid control ECU) ground circuit

  • Brake booster with master cylinder assembly (skid control ECU)

WIRING DIAGRAM

B002I92C02

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Note


  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

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  • Before measuring the resistance of the CAN bus, turn the power switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notice before proceeding with work.

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  • Some parts must be initialized and set when replacing or removing and installing parts.

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

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

    DTC check procedure: Turn the power switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.

  • After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

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Tech Tips


  • Operating the power switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

  • 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 (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] BRANCH WIRE)


    1. Disconnect the cable from the negative (-) auxiliary battery terminal.

    2. B002IX7C16
      *a

      Front view of wire harness connector

      (to Brake Booster with Master Cylinder Assembly [Skid Control ECU])

      Disconnect the brake booster with master cylinder assembly (skid control ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A57-37 (CA1H) - A57-38 (CA1L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. B002IX7C73
      *a

      Front view of wire harness connector

      (to Brake Booster with Master Cylinder Assembly [Skid Control ECU])

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A57-28 (GND) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω
      A57-27 (GND2) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω
      A57-26 (GND3) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω
      A57-25 (GND4) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω
      A57-24 (GND5) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω
      A57-23 (GND6) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω

    2. Reconnect the cable to the negative (-) auxiliary battery terminal.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A57-15 (BS) - Body ground Power switch off 11 to 14 V
      A57-14 (BI) - Body ground Power switch off 11 to 14 V
      A57-16 (IG1) - Body ground Power switch on (IG) 11 to 14 V
      Power switch off Below 1 V
      A57-12 (IG2) - Body ground Power switch on (IG) 11 to 14 V
      Power switch off Below 1 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) for RHD: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)