CAN COMMUNICATION SYSTEM, Diagnostic DTC:U1002

DTC Code DTC Name
U1002 Lost Communication with Gateway Module (Main Body)

DESCRIPTION


DTC No. DTC Detection Condition Trouble Area
U1002 Main body ECU cannot receive signals from all ECUs that have been memorized as those connected to the CAN MS bus.

  • Open or short in CAN MS bus main line or connector

  • Open or short in CAN MS bus branch line or connector

  • Main body ECU (Multiplex network body ECU)

  • Outer mirror control ECU assembly (Driver side)

  • Outer mirror control ECU assembly (Front passenger side)

  • Position control ECU and switch assembly

  • CAN No. 6 junction connector

Tech Tips

This diagnosis procedure is for when DTC U1002 is output by the main body ECU (Intelligent tester display: Main Body).

WIRING DIAGRAM

B001KZPE08
B001KZPE09

CAUTION / NOTICE / HINT

Note


  • 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.

  • Turn the power switch off before measuring the resistances between CAN main bus lines and between CAN branch lines.

  • Turn the power switch off before inspecting CAN bus lines for a ground short.

  • After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.

  • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power 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.

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.

PROCEDURE


  1. CHECK CAN MS BUS LINES


    1. Turn the power switch off.

    2. B001NE2E02
      Text in Illustration
      *1 DLC3
      *a

      Component with harness connected

      (CAN No. 6 Junction Connector)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition Result
      H100-1 (CANH) - H100-2 (CANL) Power switch off 54 to 69 Ω

      Below 54 Ω:

      Short circuit between bus lines

      70 Ω or more:

      Open circuit in a main bus line
      H100-1 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher

      Below 200 Ω:

      CANH ground short
      H100-2 (CANL) - H44-4 (CG) Power switch off 200 Ω or higher

      Below 200 Ω:

      CANL ground short

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition Result
      H100-1 (CANH) - H44-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANH +B short
      H100-2 (CANL) - H44-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Below 6 kΩ:

      CANL +B short
      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

    B

    CHECK FOR OPEN IN CAN MS BUS MAIN LINE (CAN NO. 6 J/C - MAIN BODY ECU) Click here

    C

    CHECK FOR SHORT IN CAN MS BUS LINES (CAN NO. 6 J/C - MAIN BODY ECU) Click here

    D

    CHECK FOR SHORT IN CAN MS BUS LINE (CAN NO. 6 J/C - MAIN BODY ECU) Click here

    A

  2. RECONFIRM DTC OUTPUT (MAIN BODY ECU)


    1. Clear the DTCs.

    2. Turn the power switch off.

    3. Turn the power switch on (IG) and recheck for DTCs.

      Result
      Result Proceed to
      U1002 is output from main body ECU A
      Other DTC is output B

    A

    REPLACE MULTIPLEX NETWORK BODY ECU (MAIN BODY ECU) Click here

    B

    GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC

  3. CHECK FOR OPEN IN CAN MS BUS MAIN LINE (CAN NO. 6 J/C - MAIN BODY ECU)


    1. B001LEVE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to CAN No. 6 Junction Connector)

      Disconnect the main body ECU main line harness connector from the CAN No. 6 junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      H100-1 (CANH) - H100-2 (CANL) Power switch off 108 to 132 Ω

    OK

    REPLACE CAN NO. 6 JUNCTION CONNECTOR

    NG

  4. CHECK FOR OPEN IN CAN MS BUS MAIN LINES (MAIN BODY ECU)


    1. Reconnect the main body ECU main line harness connector to the CAN No. 6 junction connector.

    2. B001ME7E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Main Body ECU (Multiplex Network Body ECU))

      Disconnect the main body ECU connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      H17-9 (CANP) - H17-10 (CANN) Power switch off 108 to 132 Ω

    OK

    REPLACE MULTIPLEX NETWORK BODY ECU (MAIN BODY ECU) Click here

    NG

    REPAIR OR REPLACE CAN MS BUS MAIN LINE OR CONNECTOR (CAN NO. 6 J/C - MAIN BODY ECU)

  5. CHECK FOR SHORT IN CAN MS BUS LINES (CAN NO. 6 J/C - MAIN BODY ECU)


    1. B001LEVE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to CAN No. 6 Junction Connector)

      Disconnect the main body ECU main line harness connector from the CAN No. 6 junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      H100-1 (CANH) - H100-2 (CANL) Power switch off 108 to 132 Ω

    NG

    CHECK FOR SHORT IN CAN MS BUS LINES (MAIN BODY ECU) Click here

    OK

  6. CHECK FOR SHORT IN CAN MS BUS LINES (CAN NO. 6 J/C)


    1. B001LK0E01
      Text in Illustration
      *a

      Component with harness connected

      (CAN No. 6 Junction Connector)

      Reconnect the main body ECU main line harness connector to the CAN No. 6 junction connector.

    2. Connect the probes of an ohmmeter to terminals 1 (CANH) and 2 (CANL) of the main body ECU main line harness connector.

    3. While observing the resistance value shown on the ohmmeter, disconnect branch line connectors (except H100) from the CAN No. 6 junction connector until the resistance becomes normal (between 54 and 69 Ω).

      B001LIRE02
      Text in Illustration
      *1 CAN No. 6 Junction Connector - -
      *a Junction Connector B Side *b Junction Connector A Side
      *c Earth Terminal *d

      Front view of wire harness connector

      (to CAN No. 6 Junction Connector)
      Junction Connector A Side
      Terminal No. (Symbol) Wiring Color Connected to
      H103-1 (GND) W-B Body ground
      H99-1 (CANH) R

      • Outer mirror control ECU assembly (Front passenger side)*1

      • Outer mirror control ECU assembly (Driver side)*2
      H99-2 (CANL) W
      H100-1 (CANH) G Main body ECU (Multiplex network body ECU)
      H100-2 (CANL) W
      H101-1 (CANH) L Position control ECU and switch assembly
      H101-2 (CANL) W
      H102-1 (CANH) Y

      • Outer mirror control ECU assembly (Driver side)*1

      • Outer mirror control ECU assembly (Front passenger side)*2
      H102-2 (CANL) W

      • *1: for LHD

      • *2: for RHD

      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 the branch lines.)

      		 B

    A

    REPLACE CAN NO. 6 JUNCTION CONNECTOR

    B

  7. CHECK FOR SHORT IN CAN MS BUS LINES (ECU)


    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. B001LK0E01
      Text in Illustration
      *a

      Component with harness connected

      (CAN No. 6 Junction Connector)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      H100-1 (CANH) - H100-2 (CANL) Power switch off 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 SWITCH

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINE OR CONNECTOR

  8. CHECK FOR SHORT IN CAN MS BUS LINES (MAIN BODY ECU)


    1. Reconnect the main body ECU main line harness connector to the CAN No. 6 junction connector.

    2. B001ME7E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Main Body ECU (Multiplex Network Body ECU))

      Disconnect the main body ECU connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      H17-9 (CANP) - H17-10 (CANN) Power switch off 108 to 132 Ω

    OK

    REPLACE MULTIPLEX NETWORK BODY ECU (MAIN BODY ECU) Click here

    NG

    REPAIR OR REPLACE CAN MS BUS MAIN LINE OR CONNECTOR (CAN NO. 6 J/C - MAIN BODY ECU)

  9. CHECK FOR SHORT IN CAN MS BUS LINE (CAN NO. 6 J/C - MAIN BODY ECU)


    1. B001LZOE02
      Text in Illustration
      *1 DLC3
      *a

      Rear view of wire harness connector

      (to CAN No. 6 Junction Connector)

      Disconnect the main body ECU main line harness connector from the CAN No. 6 junction connector.

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

      Standard Resistance
      Inspection for CAN Ground Short
      Tester Connection Switch Condition Specified Condition
      H100-1 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher
      H100-2 (CANL) - H44-4 (CG) Power switch off 200 Ω or higher
      Inspection for CAN +B Short
      Tester Connection Condition Specified Condition
      H100-1 (CANH) - H44-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      H100-2 (CANL) - H44-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      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 CAN MS Bus Line inspection.


    NG

    CHECK FOR SHORT IN CAN MS BUS LINE (MAIN BODY ECU) Click here

    OK

  10. CHECK FOR SHORT IN CAN MS BUS LINE (CAN NO. 6 J/C)


    1. B001NE2E02
      Text in Illustration
      *1 DLC3
      *a

      Component with harness connected

      (CAN No. 6 Junction Connector)

      Reconnect the main body ECU main line harness connector to the CAN No. 6 junction connector.

    2. Connect the probes of an ohmmeter to terminals 1 (CANH) and 2 (CANL) of the main body ECU main line harness connector and CG or BAT of the DLC3.

      Tech Tips

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

    3. While observing the resistance value shown on the ohmmeter, disconnect branch line connector (except H100) from the CAN No. 6 junction connector until the resistance becomes normal (6 kΩ or higher (for +B short) or 200 Ω or higher (for ground short)).

      B001LIRE02
      Text in Illustration
      *1 CAN No. 6 Junction Connector - -
      *a Junction Connector B Side *b Junction Connector A Side
      *c Earth Terminal *d

      Front view of wire harness connector

      (to CAN No. 6 Junction Connector)
      Junction Connector A Side
      Terminal No. (Symbol) Wiring Color Connected to
      H103-1 (GND) W-B Body ground
      H99-1 (CANH) R

      • Outer mirror control ECU assembly (Front passenger side)*1

      • Outer mirror control ECU assembly (Driver side)*2
      H99-2 (CANL) W
      H100-1 (CANH) G Main body ECU (Multiplex network body ECU)
      H100-2 (CANL) W
      H101-1 (CANH) L Position control ECU and switch assembly
      H101-2 (CANL) W
      H102-1 (CANH) Y

      • Outer mirror control ECU assembly (Driver side)*1

      • Outer mirror control ECU assembly (Front passenger side)*2
      H102-2 (CANL) W

      • *1: for LHD

      • *2: for RHD

      Result
      Result Proceed to

      The resistance between terminals CANP and BAT, or the resistance between terminals CANN 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 CANP and GND, or the resistance between terminals CANN 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 CANP and BAT, or the resistance between terminals CANN 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 CANP and GND, or the resistance between terminals CANN 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. 6 JUNCTION CONNECTOR

    B

  11. CHECK FOR SHORT IN CAN MS BUS LINE (ECU)


    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. B001NE2E02
      Text in Illustration
      *1 DLC3
      *a

      Component with harness connected

      (CAN No. 6 Junction Connector)

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

      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 CAN MS Bus Line inspection.

      Standard Resistance
      Inspection for CAN Ground Short
      Tester Connection Switch Condition Specified Condition
      H100-1 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher
      H100-2 (CANL) - H44-4 (CG) Power switch off 200 Ω or higher
      Inspection for CAN +B Short
      Tester Connection Condition Specified Condition
      H100-1 (CANH) - H44-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      H100-2 (CANL) - H44-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Tech Tips

      If the resistance becomes normal when the connector is disconnected from the ECU, there may be a short in the ECU.


    OK

    REPLACE CORRESPONDING ECU OR SWITCH

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINE OR CONNECTOR

  12. CHECK FOR SHORT IN CAN MS BUS LINE (MAIN BODY ECU)


    1. Disconnect the main body ECU connector.

    2. B001NEFE03
      Text in Illustration
      *1 DLC3
      *a

      Rear view of wire harness connector

      (to CAN No. 6 Junction Connector)

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

      Standard Resistance
      Inspection for CAN Ground Short
      Tester Connection Switch Condition Specified Condition
      H100-1 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher
      H100-2 (CANL) - H44-4 (CG) Power switch off 200 Ω or higher
      Inspection for CAN +B Short
      Tester Connection Condition Specified Condition
      H100-1 (CANH) - H44-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      H100-2 (CANL) - H44-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      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 CAN MS Bus Line inspection.


    OK

    REPLACE MULTIPLEX NETWORK BODY ECU (MAIN BODY ECU) Click here

    NG

    REPAIR OR REPLACE CAN MS BUS MAIN LINE OR CONNECTOR (CAN NO. 6 J/C - MAIN BODY ECU)