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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 resistances 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 TO B+ IN CAN BUS WIRE 
    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) - J21-16 (BAT) Cable from negative battery terminal disconnected 6 kΩ or higher
      J21-14 (CANL) - J21-16 (BAT) Cable from negative battery terminal disconnected 6 kΩ or higher
      4. Fig 2: Identifying J21 Connector Terminal
      G05754114Courtesy 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 TO B+ IN CAN BUS WIRE 
    1. Disconnect connectors from the CAN LH junction connector or CAN RH 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 CAN LH junction connector and CAN RH junction connector

    2. Using an ohmmeter, measure the resistance between terminals 6 (CANH) and 16 (BAT), and between terminals 14 (CANL) and 16 (BAT) of the DLC3 each time a connector is disconnected.
      Fig 3: Identifying J21 Connector Terminal
      G05754188Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 4: CAN Communication System Diagram
      G05754118Courtesy 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 to B+ in 2 or more CAN bus lines.

      Result 

      DTC RESULT REFERENCE

      Symptom Proceed to
      The resistance between terminals 6 (CANH) and 16 (BAT), or the resistance between 14 (CANL) and 16 (BAT) is still below 1 MΩ when all the specified connectors are disconnected from the CAN junction connector. (There is a short to B+ in the CAN main bus lines between the CAN LH junction connector and CAN RH junction connector.) A
      The resistance between terminals 6 (CANH) and 16 (BAT), or the resistance between 14 (CANL) and 16 (BAT) becomes normal (1 MΩ or more) when a connector is disconnected from the CAN junction connector. (There is a short to B+ in one of the areas that relate to one or more of the disconnected bus lines.) B
    3. When there is a short to B+ 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 connector, except for the one that was disconnected last (the bus line that is shorted to B+) Check that the resistance shown on the tester is normal (1 MΩ or more) to confirm that there is a short to B+ in the one bus 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

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

    B: Go to Next Step 

  4. RECONNECT CONNECTOR 
    1. Reconnect the connector of the bus line that is shorted to B+ to the CAN junction connector (the connector that caused the bus line resistance to change to 1 MΩ or more when it was disconnected)
  5. CHECK FOR SHORT TO B+ IN CAN BUS WIRE 
    1. Disconnect the connector that includes terminals CANH and CANL from the ECU (or sensor) to which the bus line shorted to B+ 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) - J21-16 (BAT) Cable from negative battery terminal disconnected 6 kΩ or higher
      J21-14 (CANL) - J21-16 (BAT) Cable from negative battery terminal disconnected 6 kΩ or higher
      Fig 7: Identifying J21 Connector Terminal
      G05754114Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT

      If the resistance changes to 1 MΩ or higher 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 BUS LINE OR CONNECTOR 

    OK: REPLACE CORRESPONDING ECU OR SENSOR 

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