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CAN COMMUNICATION SYSTEM(w/ Central Gateway ECU) Check Bus 1 Line for Short to GND

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DTC Code DTC Name
  Check Bus 1 Line for Short to GND
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DESCRIPTION

There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminal 15 (CA5H) of the central gateway ECU and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU and terminal 4 (CG) of the DLC3.

Symptom Trouble Area
No resistance exists between terminal 15 (CA5H) of the central gateway ECU and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU and terminal 4 (CG) of the DLC3.

  • Short to ground in bus 1 main lines

  • Short to ground in bus 1 branch lines

  • Central gateway ECU

  • Forward recognition camera*1

  • Driving support ECU assembly*1

  • Millimeter wave radar sensor assembly*1

  • Blind spot monitor sensor LH*2

  • Hybrid vehicle control ECU assembly

  • No. 4 CAN junction connector

  • No. 5 CAN junction connector

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WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note:

  • Before measuring the resistance of the CAN bus, turn the power switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work (Click here).

  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output (Click here).

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • DTC check procedure: Turn the power switch on (IG), turn the LDA main switch on, turn the blind spot monitor main switch on, wait at least 52 seconds and then drive the vehicle at a speed of 36 km/h (22 mph) or more for 7 seconds or more.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed (Click here).

Tip:

  • Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

  • Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines. When the connectors have been disconnected from the CAN junction connector, 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.

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PROCEDURE


  1. Click here

    CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU)


    1. Disconnect the cable from the negative (-) auxiliary battery terminal.

    2. A0005HBE01

      Disconnect the H201 No. 4 CAN junction connector.

      Tip:

      • 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.

      Table 1. Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 4 CAN Junction Connector)

      		 *b to Central Gateway ECU
    3. A0006P5E02

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H195-15 (CA5H) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      H195-16 (CA5L) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      Table 2. Text in Illustration
      *a

      Component with harness connected

      (Central Gateway ECU)

  2. Click here

    CHECK FOR SHORT TO GND IN CAN BUS LINE (BRANCH LINE)


    1. Reconnect the H201 No. 4 CAN junction connector.

    2. A0006P5E02

      Connect the probes of an electrical tester to terminals 15 (CA5H) and 10 (GND), or between terminals 16 (CA5L) and 10 (GND) of the central gateway ECU.

      Table 3. Text in Illustration
      *a

      Component with harness connected

      (Central Gateway ECU)
    3. A0008A4E05
      A00068ZE08
      A0005CPE03

      While observing the resistance value shown on the tester, disconnect connectors (H203, H205, H204 and U26) from the No. 4 CAN junction connector or No. 5 CAN junction connector one by one until the resistance becomes normal (200 Ω or higher).

      Tip:

      • Disconnect the branch line connectors other than CAN main bus line connector.

      • 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.

      Table 4. Text in Illustration
      *A w/ Lexus Safety System + *B w/ Blind Spot Monitor System
      *1 Forward Recognition Camera *2 Driving Support ECU Assembly
      *3 Millimeter Wave Radar Sensor Assembly *4 Central Gateway ECU
      *5 No. 4 CAN Junction Connector *6 Hybrid Vehicle Control ECU Assembly
      *7 Blind Spot Monitor Sensor LH *8 No. 5 CAN Junction Connector
      Table 5. Text in Illustration
      *a

      Component without harness connected

      (No. 4 CAN Junction Connector)

      		 - -
      Table 6. Wiring Color
      No. 4 CAN Junction Connector Code Color (CANH Side) Color (CANL Side)
      Millimeter wave radar sensor assembly* H204 Y LG
      Central gateway ECU H201 L LG
      No. 5 CAN junction connector H202 G LG
      Forward recognition camera* H203 R LG
      Driving support ECU assembly* H205 B LG

      • *: w/ Lexus Safety System +

      Table 7. Text in Illustration
      *a

      Component without harness connected

      (No. 5 CAN Junction Connector)

      		 - -
      Table 8. Wiring Color
      CAN Junction Connector RH1 Side Code Color (CANH Side) Color (CANL Side)
      Blind spot monitor sensor LH* U26 V LG
      Hybrid vehicle control ECU assembly U28 Y LG
      No. 4 CAN junction connector U25 G LG

      • *: w/ Blind Spot Monitor System

      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 15 (CA5H) and 10 (GND), or the resistance between 16 (CA5L) and 10 (GND) 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. 4 CAN junction connector and No. 5 CAN junction connector.) A
      The resistance between terminals 15 (CA5H) and 10 (GND), or the resistance between 16 (CA5L) and 10 (GND) becomes normal (200 Ω or higher) 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 connector, 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 higher) to confirm that there is a short to GND in the one branch line only.


  3. Click here

    CHECK FOR SHORT TO GND IN CAN BUS LINE (HYBRID VEHICLE CONTROL ECU ASSEMBLY)


    1. Reconnect the all connector of the No. 4 CAN junction connector and No. 5 CAN junction connector.

    2. A0008U0E01

      Disconnect the U28 No. 5 CAN junction connector.

      Tip:

      • 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.

      Table 9. Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 5 CAN Junction Connector)

      		 *b to Hybrid vehicle control ECU assembly
    3. A0006P5E02

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H195-15 (CA5H) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      H195-16 (CA5L) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      Table 10. Text in Illustration
      *a

      Component with harness connected

      (Central Gateway ECU)
      Result
      Symptom Proceed to
      The resistance between terminals 15 (CA5H) and 10 (GND), or the resistance between 16 (CA5L) and 10 (GND) is still below 200 Ω when a connector is disconnected from the No. 5 CAN junction connector. A
      The resistance between terminals 15 (CA5H) and 10 (GND), or the resistance between 16 (CA5L) and 10 (GND) becomes normal (200 kΩ or higher) when a connector is disconnected from the No. 5 CAN junction connector. B

  4. Click here

    CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 4 CAN J/C)


    1. Reconnect the U28 No. 5 CAN junction connector.

    2. A0007GFE01

      Disconnect the H202 No. 4 CAN junction connector.

      Tip:

      • 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.

      Table 11. Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 4 CAN Junction Connector)

      		 *b to No. 5 CAN Junction Connector
    3. A0006P5E02

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H195-15 (CA5H) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      H195-16 (CA5L) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      Table 12. Text in Illustration
      *a

      Component with harness connected

      (Central Gateway ECU)

    • OKClick here
    • NG

      REPLACE NO. 4 CAN JUNCTION CONNECTOR

  5. Click here

    CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 4 CAN J/C - NO. 5 CAN J/C)


    1. Reconnect the H202 No. 4 CAN junction connector.

    2. A0007PKE01

      Disconnect the U25 No. 5 CAN junction connector.

      Tip:

      • 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.

      Table 13. Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 5 CAN Junction Connector)

      		 *b to No. 4 CAN Junction Connector
    3. A0006P5E02

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H195-15 (CA5H) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      H195-16 (CA5L) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      Table 14. Text in Illustration
      *a

      Component with harness connected

      (Central Gateway ECU)

    • OK

      REPLACE NO. 5 CAN JUNCTION CONNECTOR

    • NG

      REPAIR OR REPLACE CAN MAIN BUS LINE (NO. 4 CAN J/C - NO. 5 CAN J/C)

  6. Click here

    CHECK FOR SHORT TO GND IN CAN BUS LINE (ECU, SENSOR)


    1. Reconnect the connector of the branch 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 higher when it was disconnected).

    2. Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the bus line shorted to GND is connected (Click here).

    3. A0006P5E02

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H195-15 (CA5H) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      H195-16 (CA5L) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      Table 15. Text in Illustration
      *a

      Component with harness connected

      (Central Gateway ECU)
      Tip:

      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.


    • OK

      REPLACE CORRESPONDING ECU OR SENSOR

    • NG

      REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINE OR CONNECTOR

  7. Click here

    CHECK FOR SHORT TO GND IN CAN BUS LINE (HYBRID VEHICLE CONTROL ECU ASSEMBLY - NO. 5 CAN J/C)


    1. Reconnect the U28 No. 5 CAN junction connector

    2. Disconnect the H211 Hybrid vehicle control ECU assembly connector.

    3. A0006P5E02

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H195-15 (CA5H) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      H195-16 (CA5L) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      Table 16. Text in Illustration
      *a

      Component with harness connected

      (Central Gateway ECU)

    • OK

      REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY (Click here)

    • NG

      REPAIR OR REPLACE CAN MAIN BUS LINE (HYBRID VEHICLE CONTROL ECU ASSEMBLY)

  8. Click here

    CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU - NO. 4 CAN J/C)


    1. Reconnect the H201 No. 4 CAN junction connector.

    2. A0007OCE02

      Disconnect the H195 central gateway ECU connector.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H195-15 (CA5H) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      H195-16 (CA5L) - H195-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      Table 17. Text in Illustration
      *a

      Front view of wire harness connector

      (to Central Gateway ECU)

    • OK

      REPLACE CENTRAL GATEWAY ECU (Click here)

    • NG

      REPAIR OR REPLACE CAN MAIN BUS LINE (CENTRAL GATEWAY ECU)