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Diagnosis System

WARNING: This page is about a different car, the 2008 Toyota Yaris. However, it is still accessible from the selected car via links, so may be relevant.
  1. BUS CHECK 
    1. Select "CAN Bus Check" from the "System Select" screen on the Techstream.

      HINT:

      If any properly connected ECUs or sensors are not displayed, there is a communication stop in the system (See HOW TO PROCEED WITH TROUBLESHOOTING  ).

      Display the "Communication Bus Check" screen for approximately 1 minute and check for ECUs and sensors that are not indicated on the screen.

  2. CHECK INSTALLED SYSTEMS (ECUS AND SENSORS) THAT ADOPT CAN COMMUNICATION 
    1. Systems (ECUs and sensors) that adopt CAN communication vary depending on the vehicle's optional settings. Check which systems (ECUs, sensors) are installed on the vehicle.
      ECU/SENSOR NAME REFERENCE CHART

      ECU/Sensor name Check method
      Brake actuator (Skid control ECU) Vehicle with ABS
      Power steering ECU Installed on all vehicles
      ECM Installed on all vehicles
      Center airbag sensor assembly Installed on all vehicles
      Air conditioning amplifier Vehicle with air conditioning or PTC heater
      Combination meter ECU Installed on all vehicles
      Main body ECU Installed on all vehicles
  3. DTC TABLE BY ECU 

    HINT:

    • In the CAN communication system, CAN communication system DTCs output by the ECU can be displayed by using a Techstream.
    • If CAN communication system DTCs are output, trouble cannot be determined solely from the DTCs. Perform troubleshooting according to "HOW TO PROCEED WITH TROUBLESHOOTING " .
    1. BRAKE ACTUATOR (SKID CONTROL ECU)

      HINT:

      DTC communication uses the CAN communication system.

      DTC CHART

      DTC No. Detection Item
      U0073/94 Control Module Communication Bus OFF
    2. POWER STEERING ECU

      HINT:

      DTC communication uses the SIL Line.

      DTC CHART

      DTC No. Detection Item
      U0073*(2) Control Module Communication Bus OFF
      U0100*(1) Lost Communication with ECM
      U0105*(2) Lost Communication with ECM
      U0121*(1), *(3) Lost Communication with Anti-lock Brake System (ABS) Control Module
      U0129*(1), *(3) Lost Communication with Brake System Control Module
      (1) For Hatchback only.

      (2) For Sedan only.

      (3) For vehicle with ABS only.
    3. COMBINATION METER ASSEMBLY

      HINT:

      DTC communication uses the CAN communication system.

      DTC CHART

      DTC No. Detection Item
      U0100 Lost Communication with ECM/PCM "A"
      U0129(1) Lost Communication with Brake System Control Module
      (1) For vehicle with ABS only.
    4. AIR CONDITIONING AMPLIFIER

      HINT:

      DTC communication uses the CAN communication system.

      DTC CHART

      DTC No. Detection Item
      B1499/99 Multiplex Communication Circuit
    5. MAIN BODY ECU

      HINT:

      • The main body ECU is connected to the CAN communication system but CAN communication DTCs are not output.
      • If "Main Body" is not displayed on the "Communication Bus Check" screen on the Techstream, proceed to "MAIN BODY ECU COMMUNICATION STOP MODE ."
    6. CENTER AIRBAG SENSOR ASSEMBLY

      HINT:

      • The center airbag sensor assembly is connected to the CAN communication system but CAN communication DTCs are not output.
      • If "SRS Airbag" is not displayed on the "Communication Bus Check" screen on the Techstream, proceed to "CENTER AIRBAG SENSOR COMMUNICATION STOP MODE. "
    7. ECM

      HINT:

      • The ECM is connected to the CAN communication system but CAN communication DTCs are not output.
      • If "Engine" is not displayed on the "Communication Bus Check" screen on the techstream, proceed to "ECM COMMUNICATION STOP MODE. "
  4. DTC COMBINATION TABLE 
    DTC CHART

    DTC Trouble Mode
    Output from Output DTC Brake Actuator (Skid Control ECU) Communication Stop Mode Power Steering ECU Communication Stop Mode ECM Communication Stop Mode Center Airbag Sensor Communication Stop Mode Air Conditioning Amplifier Communication Stop Mode Combination Meter ECU Communication Stop Mode Main Body ECU Communication Stop Mode
    Brake Actuator (Skid Control ECU) U0073/94 ◦*1 X X X X X X
    Power Steering ECU U0073*4 X ◦ X X X X X
    U0100*3
    U0105*4    		 X ◦ ◦ X X X X
    U0129*3
    U0121*4    		 ◦ ◦ X X X X X
    Combination Meter ECU U0100 X X ◦ X X X X
    U0129 ◦ X X X X X X
    Air Conditioning Amplifier B1499/99 X X ◦*2 X X ◦*2 X
    No DTC X X X ◦ ◦ X ◦

    HINT:

    • ◦: It is necessary to check for the trouble mode.
    • X: Not output
    • *1: The brake actuator (skid control ECU) detects U0073/94 when DTC communication fails in succession. However, this DTC may not be output when the CAN communication system malfunctions.
    • *2: This DTC is output when communication failures from the ECM and the combination meter ECU occur.
    • *3: For Hatchback only.
    • *4: For Sedan only.
    1. Perform troubleshooting according to the combination of DTCs output.

      HINT:

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