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

DESCRIPTION

Detection Item Symptom Trouble Area
Skid Control ECU Communication Stop Mode

Either condition is met:


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

    Click here

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

    Click here


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

A004FKGE02

CAUTION / NOTICE / HINT

Note


  • Before measuring the resistance of the CAN bus, turn the ignition 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 ignition 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 notices before proceeding with work Click here.

  • 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 Click here.

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

  • DTC check procedure: Turn the ignition switch to ON (IG), turn the cruise control system on using the cruise control main switch (ON/OFF switch), wait at least 60 seconds, and then drive the vehicle at a speed of 20 km/h (12 mph) or more.

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

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 DTC (BRAKE CONTROL SYSTEM)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Chassis / ABS/VSC/TRC / Trouble Codes.

      OK
      DTC C1241 is not output.

    NG

    GO TO DIAGNOSIS PROCEDURES INDICATED BY OUTPUT DTC Click here

    OK

  2. CHECK FOR OPEN IN CAN BUS LINES (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY BRANCH LINE)


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

    2. A004FZ3E01
      Text in Illustration
      *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
      A29-37 (CA1H) - A29-38 (CA1L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    A

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Click here

    C

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY)