CAN COMMUNICATION SYSTEM(w/o Central Gateway ECU), Diagnostic DTC:U1002

DTC Code DTC Name
U1002 Lost Communication with Gateway Module (Power Management1)

DESCRIPTION


DTC No. DTC Detection Condition Trouble Area
U1002 Power management control ECU cannot receive signals from all ECUs that have been memorized as those connected to sub bus 11.

  • Open or short in sub bus 11 main line or connector

  • Open or short in sub bus 11 branch line or connector

  • Power management control ECU

  • Driving support ECU assembly

  • Seat belt control ECU

  • Parking assist ECU

  • CAN No. 4 junction connector

Tech Tips

This diagnosis procedure is for when DTC U1002 is output by the power management control ECU (GTS display: PM1 Gateway).

WIRING DIAGRAM

A005E0FE07

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, 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), wait at least 20 seconds, and then drive the vehicle at a speed of 50 km/h (31 mph) or more at least 1.72 seconds.

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

Tech Tips


  • 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 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.

PROCEDURE


  1. CHECK SUB BUS 11


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

    2. A0059TBE03
      Text in Illustration
      *a

      Component with harness connected

      (Power Management Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Result
      L5-34 (CA2H) - L5-35 (CA2L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω

      Below 54 Ω:

      Short circuit between bus lines

      70 Ω or higher:

      Open circuit in a main bus line
      L5-34 (CA2H) - L5-6 (E1) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      Below 200 Ω:

      CANH ground short
      L5-35 (CA2L) - L5-6 (E1) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      Below 200 Ω:

      CANL ground short

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

      Standard Resistance
      Tester Connection Condition Specified Condition Result
      L5-34 (CA2H) - L5-1 (AM22) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANH +B short
      L5-35 (CA2L) - L5-1 (AM22) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANL +B short

      Tech Tips

      When the value is as specified, clear and recheck for DTCs. When no DTCs are output, check for malfunctions such as damage or improper connection of the relevant connectors.

      Result
      Result Proceed to
      OK A
      Open circuit in CAN main bus line B
      Short circuit between bus lines C

      • Ground short

      • +B short

      		 D

    A

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    C

    CHECK FOR SHORT IN SUB BUS 11 LINES (POWER MANAGEMENT CONTROL ECU) Click here

    D

    CHECK FOR SHORT IN SUB BUS 11 BUS LINE (POWER MANAGEMENT CONTROL ECU) Click here

    B

  2. CHECK FOR OPEN IN SUB BUS 11 MAIN LINES (POWER MANAGEMENT CONTROL ECU - CAN NO. 4 J/C)


    1. A005CD8E03
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Disconnect the power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L5-34 (CA2H) - L5-35 (CA2L) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    NG

  3. CHECK FOR OPEN IN SUB BUS 11 MAIN LINES (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)


    1. Reconnect the power management control ECU connector.

    2. A005DZYE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to CAN No. 4 Junction Connector)
      *b Junction Connector A Side
      *c Wiring Color: B
      *d Wiring Color: W

      Disconnect the power management control ECU main line connector from the CAN No. 4 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L100-1 (CANH) - L100-2 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Power management control ECU

      Note


      • Before disconnecting the connector, make a note of where it is connected.

      • Reconnect the connector to its original position.


    OK

    REPLACE CAN NO. 4 JUNCTION CONNECTOR

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)

  4. CHECK FOR SHORT IN SUB BUS 11 LINES (POWER MANAGEMENT CONTROL ECU)


    1. A005ATVE03
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Disconnect the power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L5-34 (CA2H) - L5-35 (CA2L) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    NG

  5. CHECK FOR SHORT IN SUB BUS 11 LINES (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)


    1. Reconnect the power management control ECU connector.

    2. A005DZYE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to CAN No. 4 Junction Connector)
      *b Junction Connector A Side
      *c Wiring Color: B
      *d Wiring Color: W

      Disconnect the power management control ECU main line connector from the CAN No. 4 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L100-1 (CANH) - L100-2 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Power management control ECU

      Note


      • Before disconnecting the connector, make a note of where it is connected.

      • Reconnect the connector to its original position.


    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)

    OK

  6. CHECK FOR SHORT IN SUB BUS 11 LINES (CAN NO. 4 J/C)


    1. Reconnect the power management control ECU main line connector to the CAN No. 4 junction connector.

    2. A005DPXE02
      Text in Illustration
      *a

      Component with harness connector

      (Power Management Control ECU)

      Connect the probes of an ohmmeter to terminals 34 (CA2H) and 35 (CA2L) of the power management control ECU.

    3. While observing the resistance value shown on the ohmmeter, disconnect branch line connectors (except L100) from the CAN No. 4 junction connector until the resistance becomes normal (between 54 and 69 Ω).

      A005DL3E02
      Text in Illustration
      *1 CAN No. 4 Junction Connector - -
      *a Junction Connector A Side *b Junction Connector B Side
      *c Earth Terminal *d

      Front view of wire harness connector

      (to CAN No. 4 Junction Connector)
      Junction Connector A Side
      Terminal No. (Symbol) Wiring Color Connected to
      L99-1 (CANH) B Parking assist ECU
      L99-2 (CANL) L
      L100-1 (CANH) B

      Power management control ECU

      (for Sub bus 11)
      L100-2 (CANL) W
      Junction Connector B Side
      Terminal No. (Symbol) Wiring Color Connected to
      L96-1 (GND) W-B Body ground
      L97-1 (CANH) B Seat belt control ECU
      L97-2 (CANL) G
      L98-1 (CANH) B Driving support ECU assembly
      L98-2 (CANL) R

      Tech Tips


      • 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.

        Result
        Result Proceed to

        The resistance is still below 54 Ω when all the specified connectors are disconnected.

        (There is no short 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

    A

    REPLACE CAN NO. 4 JUNCTION CONNECTOR

    B

  7. CHECK FOR SHORT IN SUB BUS 11 LINES (ECUS)


    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 terminals CANH and CANL from the ECU to which the short-circuited branch line is connected.

    3. A005E83E03
      Text in Illustration
      *a

      Component with harness connector

      (Power Management Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L5-34 (CA2H) - L5-35 (CA2L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω

      Tech Tips

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


    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINE OR CONNECTOR

  8. CHECK FOR SHORT IN SUB BUS 11 BUS LINE (POWER MANAGEMENT CONTROL ECU)


    1. A005B8AE03
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Disconnect the power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Purpose
      L5-34 (CA2H) - L5-6 (E1) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Inspection for CANH ground short
      L5-35 (CA2L) - L5-6 (E1) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Inspection for CANL ground short
      L5-34 (CA2H) - L5-1 (AM22) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Inspection for CANH +B short
      L5-35 (CA2L) - L5-1 (AM22) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Inspection for CANL +B short

      Tech Tips

      It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sub Bus 11 inspection.

      Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sub Bus 11 inspection.


    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    NG

  9. CHECK FOR SHORT IN SUB BUS 11 LINE (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)


    1. A005DZYE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to CAN No. 4 Junction Connector)
      *b Junction Connector A Side
      *c Wiring Color: B
      *d Wiring Color: W

      Disconnect the power management control ECU main line connector from the CAN No. 4 junction connector.

      Note


      • Before disconnecting the connector, make a note of where it is connected.

      • Reconnect the connector to its original position.

    2. A005ABTE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Purpose
      L5-34 (CA2H) - L5-6 (E1) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Inspection for CANH ground short
      L5-35 (CA2L) - L5-6 (E1) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Inspection for CANL ground short
      L5-34 (CA2H) - L5-1 (AM22) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Inspection for CANH +B short
      L5-35 (CA2L) - L5-1 (AM22) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Inspection for CANL +B short

      Tech Tips

      It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sub Bus 11 inspection.

      Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sub Bus 11 inspection.


    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)

    OK

  10. CHECK FOR SHORT IN SUB BUS 11 LINE (CAN NO. 4 J/C)


    1. Reconnect the power management control ECU main line connector to the CAN No. 4 junction connector.

    2. A005ABTE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Connect the probes of an ohmmeter to terminals CANH or CANL and GND or +B (AM22) of the power management control ECU.

      Tech Tips


      • It is only necessary to perform the inspection for the result (short circuit) that was obtained in the Check Sub Bus 11 Line inspection.

      • 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.

    3. While observing the resistance value shown on the ohmmeter, disconnect branch line connectors (except L100) from the CAN No. 4 junction connector until the resistance becomes normal (6 kΩ or higher (for +B short) or 200 Ω or higher (for ground short)).

      A005DL3E02
      Text in Illustration
      *1 CAN No. 4 Junction Connector - -
      *a Junction Connector A Side *b Junction Connector B Side
      *c Earth Terminal *d

      Front view of wire harness connector

      (to CAN No. 4 Junction Connector)
      Junction Connector A Side
      Terminal No. (Symbol) Wiring Color Connected to
      L99-1 (CANH) B Parking assist ECU
      L99-2 (CANL) L
      L100-1 (CANH) B

      Power management control ECU

      (for Sub bus 11)
      L100-2 (CANL) W
      Junction Connector B Side
      Terminal No. (Symbol) Wiring Color Connected to
      L96-1 (GND) W-B Body ground
      L97-1 (CANH) B Seat belt control ECU
      L97-2 (CANL) G
      L98-1 (CANH) B Driving support ECU assembly
      L98-2 (CANL) R

      Tech Tips


      • 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.

        Result
        Result Proceed to

        The resistance between terminals CANH and BAT, or the resistance between terminals CANL and BAT is still below 6 kΩ when all the specified connectors are disconnected from the CAN junction connector.

        (There is no short to +B in the branch lines.)

        		 A

        The resistance between terminals CANH and GND, or the resistance between terminals CANL and GND is still below 200 Ω when all the specified connectors are disconnected from the CAN junction connector.

        (There is no short to GND in the branch lines.)

        The resistance between terminals CANH and BAT, or the resistance between terminals CANL and BAT becomes normal (6 kΩ or higher) when a connector is disconnected from the CAN junction connector.

        (There is a short to +B in one of the areas related to one or more of the disconnected branch lines.)

        		 B

        The resistance between terminals CANH and GND, or the resistance between terminals CANL and 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 related to one or more of the disconnected branch lines.)

    A

    REPLACE CAN NO. 4 JUNCTION CONNECTOR

    B

  11. CHECK FOR SHORT IN SUB BUS 11 LINE (ECUS)


    1. Reconnect the connector for the bus line that is shorted to +B or GND to the CAN junction connector (the connector that caused the bus line resistance to change to 6 kΩ or higher (for +B short) or 200 Ω or higher (for ground short) when it was disconnected).

    2. Disconnect the connector that includes terminals CANH and CANL from the ECU to which the bus line shorted to +B or GND is connected.

    3. A005ABTE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Power Management Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Purpose
      L5-34 (CA2H) - L5-6 (E1) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Inspection for CANH ground short
      L5-35 (CA2L) - L5-6 (E1) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Inspection for CANL ground short
      L5-34 (CA2H) - L5-1 (AM22) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Inspection for CANH +B short
      L5-35 (CA2L) - L5-1 (AM22) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Inspection for CANL +B short

      Tech Tips

      It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Sub Bus 11 inspection.

      Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check Sub Bus 11 inspection.


    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINE OR CONNECTOR