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Home >> Toyota >> 2015 >> Avalon Hybrid Limited >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Can Communication System (W/O Central Gateway Ecu) - Diagnostics & Circuit Tests - (Hybrid) >> CAN COMMUNICATION SYSTEM (w/o Central Gateway ECU) >> Circuit Tests >> Check CAN Bus Line for Short to GND [10/2015 - ] >> Procedure

Check CAN Bus Line for Short to GND [10/2015 - ]: Procedure

  1. CHECK FOR SHORT TO GND IN CAN BUS LINE (DLC3 BRANCH LINE) 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal.
    2. Disconnect the D75 DLC3 branch line connector.
      GTY571911Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Rear view of wire harness connector
      (to No. 1 CAN Junction Connector)
      *b to DLC3
      NOTE:
      • Before disconnecting the connector, make a note of where it is connected.
      • Reconnect the connector to its original position.
    3. Measure the resistance according to the value(s) in the table below.
      GTY608220Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      D28-6 (CANH) - D28-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      D28-14 (CANL) - D28-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      TEXT IN ILLUSTRATION

      *1 DLC3

    Result: 

    NG 

    REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3 

    Result: 

    OK 

    See step  2

  2. CHECK FOR SHORT TO GND IN CAN BUS LINE 
    1. Reconnect the D75 DLC3 branch line connector.
    2. Disconnect the connectors from the No. 1 CAN junction connector and No. 2 CAN junction connector one at a time.

      HINT: 

      Disconnect the ECU and sensor connectors other than the DLC3 branch lines and CAN main bus lines between the No. 1 CAN junction connector and No. 2 CAN junction connector.

      GTY608220Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 DLC3
    3. Using an ohmmeter, measure the resistance between terminals 6 (CANH) and 4 (CG), and between terminals 14 (CANL) and 4 (CG) of the DLC3 each time a connector is disconnected.
      GTY586149Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3 *2 Skid Control ECU (Brake Booster with Master Cylinder Assembly)
      *3 Steering Sensor *4 Tire Pressure Warning ECU and Receiver
      *5 Main Body ECU (Multiplex Network Body ECU) *6 Combination Meter Assembly
      *7 Hybrid Vehicle Control ECU Assembly *8 Power Steering ECU Assembly
      *9 Airbag ECU Assembly *10 Certification ECU (Smart Key ECU Assembly)
      *11 ECM *12 Air Conditioning Amplifier Assembly
      *13 Navigation ECU Sub-assembly (for Navigation Receiver Type)
      Radio and Display Receiver Assembly (for Radio and Display Type)      		 *14 No. 1 CAN Junction Connector
      *15 No. 2 CAN Junction Connector - -
      GTY609483Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (No. 1 CAN Junction Connector)      		 - -
      WIRING COLOR

      No. 1 CAN Junction Connector Side Code Color (CANH Side) Color (CANL Side)
      CAN main bus line (bus line connecting No. 1 CAN junction connector and No. 2 CAN junction connector) D72 B W
      Combination meter assembly D73 R W
      Main body ECU (Multiplex network body ECU) D74 P W
      DLC3 D75 L W
      Steering sensor D76 V W
      Hybrid vehicle control ECU assembly D114 G W
      Skid control ECU (Brake booster with master cylinder assembly) D115 Y W
      Tire Pressure Warning ECU and Receiver D130 SB W
      GTY577743Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (No. 2 CAN Junction Connector)      		 - -
      WIRING COLOR

      No. 2 CAN Junction Connector Side Code Color (CANH Side) Color (CANL Side)
      • Navigation ECU sub-assembly*1
      • Radio and display receiver assembly*2
      		 D84 R W
      CAN main bus line (bus line connecting No. 1 CAN junction connector and No. 2 CAN junction connector) D78 B W
      Air conditioning amplifier assembly D79 BR W
      ECM D81 P W
      Certification ECU (Smart key ECU assembly) D83 L W
      Airbag ECU assembly D113 LG W
      Power steering ECU assembly D112 G W
      • *1: for Navigation receiver type
      • *2: for Radio and display type
      NOTE:

      Do not reconnect the disconnected connectors until this inspection is complete because there may be a short to GND in 2 or more CAN bus lines.

      Result

      Symptom Proceed to
      The resistance between terminals 6 (CANH) and 4 (CG), or the resistance between 14 (CANL) and 4 (CG) is still below 200 Ω when all the specified connectors are disconnected from the CAN junction connector. (There is a short to GND in the CAN main bus lines between the No. 1 CAN junction connector and No. 2 CAN junction connector.) A
      The resistance between terminals 6 (CANH) and 4 (CG), or the resistance between 14 (CANL) and 4 (CG) becomes normal (200 Ω or more) when a connector is disconnected from the CAN junction connector. (There is a short to GND in one of the areas that relate to the disconnected bus lines.) B
    4. When there is a short to GND in one or more of the bus lines that connect to an ECU (or sensor):
      1. Reconnect all of the connectors to the CAN junction connectors, except for the one that was disconnected last (the bus line that is shorted to GND). Check that the resistance shown on the tester is normal (200 Ω or more) to confirm that there is a short to GND in the one branch line only.

        HINT: 

        • Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
        • Reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
    5. When there is no short to GND in any of the bus lines that connect to the ECUs and sensors:
      1. With all the specified connectors for ECUs and sensors disconnected, proceed with the inspection of the CAN bus main lines between the No. 1 CAN junction connector and No. 2 CAN junction connector.

    Result: 

    B 

    See step  5

    Result: 

    A 

    See step  3

  3. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 1 CAN JUNCTION CONNECTOR) 
    1. Disconnect the D72 CAN main bus line connector.
      GTY563429Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Rear view of wire harness connector
      (to No. 1 CAN Junction Connector)
      *b to No. 2 CAN Junction Connector
      NOTE:
      • Before disconnecting the connector, make a note of where it is connected.
      • Reconnect the connector to its original position.
    2. Measure the resistance according to the value(s) in the table below.
      GTY608220Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      D28-6 (CANH) - D28-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      D28-14 (CANL) - D28-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      TEXT IN ILLUSTRATION

      *1 DLC3

    Result: 

    NG 

    REPLACE NO. 1 CAN JUNCTION CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 1 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR) 
    1. Reconnect the D72 CAN main bus line connector.
    2. Disconnect the D78 CAN main bus line connector.
      GTY561338Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Rear view of wire harness connector
      (to No. 2 CAN Junction Connector)
      *b to No. 1 CAN Junction Connector
      NOTE:
      • Before disconnecting the connector, make a note of where it is connected.
      • Reconnect the connector to its original position.
    3. Measure the resistance according to the value(s) in the table below.
      GTY608220Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      D28-6 (CANH) - D28-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      D28-14 (CANL) - D28-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      TEXT IN ILLUSTRATION

      *1 DLC3

    Result: 

    OK 

    REPLACE NO. 2 CAN JUNCTION CONNECTOR 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN BUS LINE (NO. 1 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR) 

  5. CHECK FOR SHORT TO GND IN CAN BUS LINE (ECU, SENSOR) 
    1. Reconnect the connector of the bus line that is shorted to GND to the CAN junction connector (the connector that caused the bus line resistance to change to 200 Ω or more when it was disconnected).
    2. Disconnect the connector that includes the DLC3 connected CAN lines (such as CANH and CANL) from the ECU (or sensor) to which the bus line shorted to GND is connected (Refer to TERMINALS OF ECU [10/2015 - ] ).
      GTY608220Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D28-6 (CANH) - D28-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      D28-14 (CANL) - D28-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      TEXT IN ILLUSTRATION

      *1 DLC3

      HINT: 

      If the resistance changes to 200 Ω or higher when the connector is disconnected from the ECU (or sensor), there may be a short in the ECU (or sensor).

    Result: 

    OK 

    REPLACE CORRESPONDING ECU OR SENSOR 

    Result: 

    NG 

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BUS LINE OR CONNECTOR 

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