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Home >> Toyota >> 2025 >> Prius XLE >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Can Communication System (HEV) - Circuit Tests (1 Of 3) & Diagnostic Codes >> CAN COMMUNICATION SYSTEM (for HEV Model) >> Check CAN Communication Connection [12/2022 - ] >> Procedure

Check CAN Communication Connection [12/2022 - ]: Procedure

  1. CHECK GTS OPERATION 
    1. Connect the GTS to the DLC3 of another vehicle.
    2. Turn the ignition switch to ON.
    3. Turn the GTS on.
    4. Check that the GTS and ECUs can communicate with the ignition switch ON.

      HINT: 

      • ECUs and sensors are not displayed on the "Communication Bus Check" screen when the GTS cannot communicate with the vehicle.
      • If communication between the GTS and ECUs is not possible, either the GTS or vehicle has a malfunction.
      • If communication between the GTS and ECUs is still not possible even when the GTS is connected to another vehicle, the GTS has a malfunction. Perform the self tests described in the GTS operator's manual. (The GTS may be malfunctioning or its battery may be discharged.)

      Result

      Result Proceed to
      OK (Communication between the GTS and the vehicle is not possible but communication is possible when connected to another vehicle.) A
      NG (Communication is not possible between the GTS and the vehicle, nor between the GTS and another vehicle.) B

    Result: 

    REFER TO GTS OPERATOR'S MANUAL 

    Result: 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (DLC3 POWER SOURCE CIRCUIT) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      K8-16 (BAT) - Body ground Ignition switch off 11 to 14 V
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      K8-4 (CG) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (DLC3 POWER SOURCE CIRCUIT) 

    Result: 

    OK 

    See step  3

  3. CHECK OPEN IN CAN BUS LINES 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      K8-6 (CANH) - K8-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal Below 70 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  4

  4. CHECK SHORT IN CAN BUS LINES 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      K8-6 (CANH) - K8-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 Ω or higher
      K8-6 (CANH) - K8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      K8-14 (CANL) - K8-4 (CG)
      K8-6 (CANH) - K8-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      K8-14 (CANL) - K8-16 (BAT)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 
    1. Disconnect the K78 central gateway ECU (network gateway ECU) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      K78-22 (GND) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω
    3. Reconnect the cable to the negative (-) auxiliary battery terminal.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      K78-1 (BATT) - Body ground Ignition switch off 11 to 14 V
      K78-2 (ACC) - Body ground Ignition switch ACC 11 to 14 V
      K78-19 (IGP) - Body ground Ignition switch ON 11 to 14 V
      K78-20 (IGR) - Body ground Ignition switch ON 11 to 14 V

      Result

      Proceed to 
      OK
      NG

    Result: 

    OK 

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) 

    Refer to REMOVAL [12/2022 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) 

  6. CHECK SHORT IN CAN BUS LINES 
    1. Disconnect the K78 central gateway ECU (network gateway ECU) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      K78-16 (CA6H) - K78-17 (CA6L) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher
      K78-16 (CA6H) - K8-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      K78-17 (CA6L) - K8-4 (CG)
      K78-16 (CA6H) - K8-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      K78-17 (CA6L) - K8-16 (BAT)

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) 

    Refer to REMOVAL [12/2022 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (DLC3 - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) 

  7. CHECK FOR OPEN IN CAN BUS LINES (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - DLC3) 
    1. Disconnect the K78 central gateway ECU (network gateway ECU) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      K78-16 (CA6H) - K8-6 (CANH) Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω
      K78-17 (CA6L) - K8-14 (CANL)

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) 

    Refer to REMOVAL [12/2022 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - DLC3)