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Check CAN Bus Lines for Short Circuit [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FOR SHORT IN CAN BUS LINES (DLC3 BRANCH LINE) 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal.
    2. Disconnect the H119 DLC3 branch line connector.
      GTY415855Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to CAN Junction Connector LH1)
      *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.
      GTY398578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      H29-6 (CANH) - H29-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 DLC3

    NG → REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3 

    OK: Go to next step 

  2. CHECK FOR SHORT IN CAN BUS LINES (BRANCH LINE) 
    1. Reconnect the H119 DLC3 branch line connector.
    2. Connect the probes of an ohmmeter to terminals 6 (CANH) and 14 (CANL) of the DLC3.
      GTY398578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 DLC3
    3. While observing the resistance value shown on the tester, disconnect connectors (H118, H120, H121, H123, H124, H127, H128, H130, H131 and H132) from the CAN junction connector LH1 or CAN junction connector RH1 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.

      GTY407368Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *A w/ Intuitive Parking Assist System *B w/ Navigation System
      *C w/ Audio and Visual System (w/ Multi-display with Parking Assist Monitor System) *D w/ Audio and Visual System (w/ Multi-display without Parking Assist Monitor System)
      *1 Clearance Warning ECU Assembly *2 ECM
      *3 Air Conditioning Amplifier Assembly *4 Airbag Sensor Assembly
      *5 Certification ECU (Smart Key ECU Assembly) *6 Power Steering ECU with Motor Assembly
      *7 Multi-media Module Receiver Assembly *8 Radio Receiver Assembly
      *9 Combination Meter Assembly *10 Power Management Control ECU
      *11 DLC3 *12 Brake Booster with Master Cylinder Assembly (Skid Control ECU)
      *13 Steering Sensor *14 Main Body ECU (Multiplex Network Body ECU)
      *15 CAN Junction Connector RH1 *16 CAN Junction Connector LH1
      GTY414807Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a Component without harness connected
      (CAN Junction Connector LH1)      		 - -
      WIRING COLOR

      CAN Junction Connector LH1 Side Code Color (CANH Side) Color (CANL Side)
      CAN main bus line (bus line connecting CAN junction connector LH1 and CAN junction connector RH1) H116 R W
      Combination meter assembly H117 G W
      Main body ECU (Multiplex network body ECU) H118 V W
      DLC3 H119 L W
      Steering sensor H120 P W
      Power management control ECU H130 B W
      Brake booster with master cylinder assembly (Skid control ECU) H131 BE W
      GTY398971Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a Component without harness connected
      (CAN Junction Connector RH1)      		 - -
      WIRING COLOR

      CAN Junction Connector RH1 Side Code Color (CANH Side) Color (CANL Side)
      Power steering ECU with motor assembly H121 B W
      CAN main bus line (bus line connecting CAN junction connector LH1 and CAN junction connector RH1) H122 R W
      Air conditioning amplifier assembly H123 G W
      Airbag sensor assembly H124 Y W
      ECM H125 L W
      Certification ECU (Smart key ECU assembly) H127 V W
      • Multi-media module receiver assembly*1*2
      • Radio receiver assembly*3
      		 H128 BE W
      Clearance warning ECU assembly*4 H132 P W
      • *1: w/ Navigation system
      • *2: w/ Audio and visual system (w/ Multi-display with parking assist monitor system)
      • *3: w/ Audio and visual system (w/ Multi-display without parking assist monitor system)
      • *4: w/ Intuitive parking assist system
      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

      Symptom Proceed to
      The resistance is still below 54 Ω when all the specified connectors are disconnected. (There are no shorts between a pair of branch lines.) A
      The resistance becomes normal (between 54 and 69 Ω) when a connector is disconnected. (There is a short between one or more pairs of branch lines.) B
    4. When there is a short in one or more of the branch lines:
      1. Reconnect all of the connectors to the CAN junction connectors, 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: 

        • 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.

    B → See step   7 

    A: Go to next step 

  3. CHECK FOR SHORT IN CAN BUS LINES (COMBINATION METER ASSEMBLY MAIN BUS LINE) 
    1. Disconnect the H117 combination meter assembly main bus line connector.
      GTY410889Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to CAN Junction Connector LH1)
      *b to Combination Meter Assembly
      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.
      GTY398578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      H29-6 (CANH) - H29-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *1 DLC3

      Result

      Symptom Proceed to
      The resistance is still below 54 Ω when the combination meter assembly connector is disconnected. (There are no shorts in the combination meter assembly or between its main bus lines.) A
      The resistance falls within the specified range (between 108 and 132 Ω) (the other terminating resistor is normal) when the combination meter assembly connector is disconnected. (There is a short in the combination meter assembly or between its main bus lines.) B

    B → See step   8 

    A: Go to next step 

  4. CHECK FOR SHORT IN CAN BUS LINES (ECM MAIN BUS LINE) 
    1. Disconnect the H125 ECM main bus line connector.
      GTY404118Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to CAN Junction Connector RH1)
      *b to ECM
      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.
      GTY398578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      H29-6 (CANH) - H29-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 DLC3

      HINT: 

      Measure the resistance with the combination meter assembly main bus line connector (I94) disconnected.

      Result

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

    B → See step   9 

    A: Go to next step 

  5. CHECK FOR SHORT IN CAN BUS LINES (CAN J/C LH1) 
    1. Disconnect the H116 CAN main bus line connector.
      GTY396145Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to CAN Junction Connector LH1)
      *b to CAN Junction Connector RH1
      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.
      GTY398578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      H29-6 (CANH) - H29-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 DLC3

    NG → REPLACE CAN JUNCTION CONNECTOR LH1 

    OK: Go to next step 

  6. CHECK FOR SHORT IN CAN BUS LINES (CAN J/C LH1 - CAN J/C RH1) 
    1. Reconnect the H116 CAN main bus line connector.
    2. Disconnect the H122 CAN main bus line connector.
      GTY400319Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to CAN Junction Connector RH1)
      *b to CAN Junction Connector LH1
      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.
      GTY398578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      H29-6 (CANH) - H29-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 DLC3

    NG → REPAIR OR REPLACE CAN MAIN BUS LINES (CAN J/C LH1 - CAN J/C RH1) 

    OK → REPLACE CAN JUNCTION CONNECTOR RH1 

  7. CHECK FOR SHORT IN CAN BUS LINES (ECU, SENSOR) 
    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).
    2. Disconnect the connector that includes the DLC3 connected CAN lines (such as CANH and CANL) from the ECU (or sensor) to which the short-circuited branch line is connected. Refer to TERMINALS OF ECU [08/2013 - ] .
    3. Measure the resistance according to the value(s) in the table below.
      GTY398578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      H29-6 (CANH) - H29-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω
      TEXT IN ILLUSTRATION

      *1 DLC3

      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 LINES OR CONNECTOR 

    OK → REPLACE CORRESPONDING ECU OR SENSOR 

  8. CHECK FOR SHORT IN CAN BUS LINES (COMBINATION METER ASSEMBLY) 
    1. Reconnect the H117 combination meter assembly main bus line connector.
    2. Disconnect the H14 combination meter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.
      GTY398578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      H29-6 (CANH) - H29-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      TEXT IN ILLUSTRATION

      *1 DLC3

      HINT: 

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

    NG → REPAIR OR REPLACE CAN MAIN BUS LINES (COMBINATION METER ASSEMBLY MAIN LINES) 

    OK → See step   10 

  9. CHECK FOR SHORT IN CAN BUS LINES (ECM) 
    1. Reconnect the H125 ECM main bus line connector.
    2. Disconnect the A22 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.
      GTY398578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      H29-6 (CANH) - H29-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 DLC3

      HINT: 

      • Measure the resistance with the combination meter assembly main bus line connector (H117) 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 MAIN BUS LINES (ECM MAIN LINES) 

    OK → See step   11 

  10. REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [08/2013 - ] 
  11. REPLACE ECM. Refer to  REMOVAL [08/2013 - ] 
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