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Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
  • Turn the engine switch off before measuring the resistance of CAN bus main wires and CAN bus branch wires.
  • After the engine switch is turned off, check that the key reminder warning system and light reminder warning system are not in operation.
  • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the engine switch, any other switches, or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

HINT:

Operating the engine switch, any switches, or any doors triggers related ECU and sensor communication with the CAN. This communication will cause the resistance value to change.

  1. CHECK FOR SHORT IN CAN BUS WIRES (DLC3 BRANCH LINE) 
    1. Turn the engine switch off
    2. Disconnect the DLC3 branch line connector (J8) from the CAN LH junction connector B side (w/o earth terminal).
      NOTE:
      • Before disconnecting the connector, make a note of where it is connected.
      • Reconnect the connector to its original position.
        Fig 1: Identifying J8 Connector Terminal
        G05754167Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below

      Standard Resistance 

      RESISTANCE REFERENCE

      Tester Connection Condition Specified Value
      J21-6(CANH) - J21-14 (CANL) Engine switch off 1 MΩ or higher
      4. Fig 2: Identifying J21 Connector Terminal
      G05754112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE DLC3 BRANCH WIRE OR CONNECTOR 

    OK: Go to Next Step 

  2. RECONNECT CONNECTOR 
    1. Reconnect the DLC3 branch line connector (J8) to the CAN LH junction connector B side (w/o earth terminal).
  3. CHECK FOR SHORT IN CAN BUS WIRES (BRANCH LINE) 
    1. Connect the probes of an ohmmeter to terminals 6 (CANH) and 14 (CANL) of the DLC3.
    2. While observing the resistance value shown on the tester, disconnect connectors J1, J3, J4, J5, J9, J82 and J83 from the CAN LH junction connector or CAN RH junction connector one by one until the resistance becomes normal (between 54 and 69 Ω)

      HINT:

      Disconnect the branch line connectors other than those of the DLC3

      Fig 3: Identifying J21 Connector Terminal
      G05754112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 4: CAN RH Junction Connector Diagram
      G05754170Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 5: CAN LH Junction Connector Diagram
      G05754115Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Wiring Color 

      WIRING COLOR SPECIFICATION

      CAN LH Junction Connector A Side (w/ Earth Terminal) Code Color (CANH Side) Color (CANL Side)
      Steering angle sensor J1 P W
      ECM J2 B W
      Seat belt control ECU J3 V W
      Center airbag sensor J4 R W

      Wiring Color 

      WIRING COLOR SPECIFICATION

      CAN LH Junction Connector B Side (w/o Earth Terminal) Code Color (CANH Side) Color (CANL Side)
      Yaw rate sensor J5 P W
      CAN main bus line (bus line connecting CAN LH junction connector and CAN RH junction connector) J7 B W
      DLC3 J8 G W
      Distance control ECU J9 GR W
      Fig 6: CAN RH Junction Connector Diagram
      G05754116Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Wiring Color 

      WIRING COLOR SPECIFICATION

      CAN RH Junction Connector A Side (w/ Earth Terminal) Code Color (CANH Side) Color (CANL Side)
      CAN main bus line (bus line connecting CAN RH junction connector and CAN LH junction connector) J81 B W
      Power steering ECU J82 P W
      Skid control ECU J83 R W

      Wiring Color 

      WIRING COLOR SPECIFICATION

      CAN RH Junction Connector B Side (w/o Earth Terminal) Code Color (CANH Side) Color (CANL Side)
      Gateway ECU J84 B W
      NOTE: Do not reconnect the disconnected connectors until this inspection is complete because there may be a short in 2 or more branch lines.

      Result 

      DTC RESULT REFERENCE

      Symptom Proceed to
      The resistance is still below 54 Ω when all the specified connectors are disconnected (There are no shorts in the branch lines.) A
      The resistance becomes normal (between 54 and 69 Ω) when a connector is disconnected. (There is a short in one or more of the branch lines.) B
    3. When there is a short in one or more of the branch lines:
      1. Reconnect all of the connectors to the CAN junction connector, except for the one that was disconnected last (the short-circuited bus line). Check that the resistance shown on the tester is normal (between 54 and 69 Ω) to confirm that there is a short in the one branch line only

        HINT

        • The connectors connected to the CAN junction connector can be distinguished according to the color of the communication bus lines and the shape of the connectors
        • Reconnecting the connectors to non-specified positions on the CAN junction connector does not affect system operation However, it is preferred to reconnect the connectors to their specified positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier

    B: Go to step  9

    A: Go to Next Step 

  4. CHECK FOR SHORT IN CAN BUS WIRES (GATEWAY ECU MAIN BUS LINE) 
    1. Disconnect the gateway ECU main bus line connector (J84) from the CAN RH junction connector B side (w/o earth terminal)
      NOTE:
      • Before disconnecting the connector, make a note of where it is connected.
      • Reconnect the connector to its original position.
        Fig 7: Identifying J84 Connector Terminal
        G05754160Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      RESISTANCE REFERENCE

      Tester Connection Condition Specified Value
      J21-6(CANH) - J21-14 (CANL) Engine switch off 108 to 132 Ω
      Fig 8: Identifying J21 Connector Terminal
      G05754112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Result 

      DTC RESULT REFERENCE

      Symptom Proceed to
      The resistance is still below 54 Ω when the gateway ECU connector is disconnected. (There are no shorts in the gateway ECU main bus lines.) A
      The resistance falls within the specified range (between 108 and 132 Ω) (either of the terminating resistances is normal) when the gateway ECU connector is disconnected. (There is a short in the gateway ECU main bus lines.) B

    B: Go to step  11

    A: Go to Next Step 

  5. CHECK FOR SHORT IN CAN BUS WIRES (ECM MAIN BUS LINE) 
    1. Disconnect the ECM main bus line connector (J2) from the CAN LH junction connector A side (w/ earth terminal)
      NOTE:
      • Before disconnecting the connector, make a note of where it is connected.
      • Reconnect the connector to its original position.
        Fig 9: Identifying J2 Connector Terminal
        G05754164Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      RESISTANCE REFERENCE

      Tester Connection Condition Specified Value
      J21-6(CANH) - J21-14 (CANL) Engine switch off 1 MΩ or higher

      HINT.

      Measure the resistance with the gateway ECU main bus line connector (J84) disconnected

      Fig 10: Identifying J21 Connector Terminal
      G05754112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Result 

      DTC RESULT REFERENCE

      Symptom Proceed to
      The resistance is still below 1 MΩ when the ECM connector is disconnected. (There are no shorts in the ECM main bus lines.) A
      The resistance becomes 1 MΩ or more when the ECM connector is disconnected. (There is a short in the ECM main bus lines.) B

    B: Go to step  13

    A: Go to Next Step 

  6. CHECK CAN LH JUNCTION CONNECTOR 
    1. Disconnect the CAN main bus line connector (J7) from the CAN LH junction connector B side (w/o earth terminal)
      NOTE:
      • Before disconnecting the connector, make a note of where it is connected.
      • Reconnect the connector to its original position.
        Fig 11: Identifying J7 Connector Terminal
        G05754177Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below

      Standard Resistance 

      RESISTANCE REFERENCE

      Tester Connection Condition Specified Value
      J21-6(CANH) - J21-14 (CANL) Engine switch off 1 MΩ or higher
      3. Fig 12: Identifying J21 Connector Terminal
      G05754112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE CAN LH JUNCTION CONNECTOR 

    OK: Go to Next Step 

  7. RECONNECT CONNECTOR 
    1. Reconnect the CAN main bus line connector (J7) to the CAN LH junction connector B side (w/o earth terminal).
  8. CHECK CAN RH JUNCTION CONNECTOR 
    1. Disconnect the CAN main bus line connector (J81) from the CAN RH junction connector A side (w/ earth terminal)
      NOTE:
      • Before disconnecting the connector, make a note of where it is connected.
      • Reconnect the connector to its original position.
        Fig 13: Identifying J81 Connector Terminal
        G05754179Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below

      Standard Resistance 

      RESISTANCE REFERENCE

      Tester Connection Condition Specified Value
      J21-6(CANH) - J21-14 (CANL) Engine switch off 1 MΩ or higher
      3. Fig 14: Identifying J21 Connector Terminal
      G05754112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: REPLACE CAN RH JUNCTION CONNECTOR 

    NG: REPAIR OR REPLACE CAN BUS MAIN WIRE (CAN LH JUNCTION CONNECTOR - CAN RH JUNCTION CONNECTOR) 

  9. RECONNECT CONNECTOR 
    1. Reconnect the connector for the short-circuited branch line to the CAN junction connector (the connector that caused the bus line resistance to become normal (between 54 and 69 Ω) when it was disconnected)
  10. CHECK FOR SHORT IN CAN BUS WIRES 
    1. Disconnect the connector that includes terminals CANH and CANL from the ECU (or sensor) to which the short-circuited branch line is connected (See TERMINALS OF ECU  ).
    2. Measure the resistance according to the value(s) in the table below

      Standard Resistance 

      RESISTANCE REFERENCE

      Tester Connection Condition Specified Value
      J21-6(CANH) - J21-14 (CANL) Engine switch off 1 MΩ or higher
      Fig 15: Identifying J21 Connector Terminal
      G05754112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      If the resistance becomes normal (between 54 and 69 Ω) when the connector is disconnected from the ECU (or sensor), there may be a short in the ECU (or sensor)

    NG: REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH WIRE OR CONNECTOR 

    OK: REPLACE CORRESPONDING ECU OR SENSOR 

  11. RECONNECT CONNECTOR 
    1. Reconnect the gateway ECU main bus line connector (J84) to the CAN RH junction connector B side (w/o earth terminal).
  12. CHECK FOR SHORT IN CAN BUS WIRES (GATEWAY ECU) 
    1. Disconnect the gateway ECU connector (J76)
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      RESISTANCE REFERENCE

      Tester Connection Condition Specified Value
      J21-6(CANH) - J21-14 (CANL) Engine switch off 108 to 132 Ω
      Fig 16: Identifying J21 Connector Terminal
      G05754112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT

      If the resistance becomes normal (between 108 to 132 Ω) when the connector is disconnected, there may be a short in the gateway ECU.

    NG: REPAIR OR REPLACE CAN BUS MAIN WIRE (GATEWAY ECU MAIN BUS LINE) 

    OK: REPLACE GATEWAY ECU  (See NETWORK GATEWAY ECU  )

  13. RECONNECT CONNECTOR 
    1. Reconnect the ECM main bus line connector (J2) to the CAN LH junction connector A side (w/ earth terminal)
  14. CHECK FOR SHORT IN CAN BUS WIRES (ECM) 
    1. Disconnect the ECM connector (A6)
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      RESISTANCE REFERENCE

      Tester Connection Condition Specified Value
      J21-6(CANH) - J21-14 (CANL) Engine switch off 1 MΩ or higher
      Fig 17: Identifying J21 Connector Terminal
      G05754112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT

      • Measure the resistance with the gateway ECU main bus line connector (J84) disconnected
      • If the resistance changes to 1 MΩ or more when the connector is disconnected, there may be a short in the ECM

    NG: REPAIR OR REPLACE CAN BUS MAIN WIRE (ECM MAIN BUS LINE) 

    OK: REPLACE ECM  (See REMOVAL )

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