DTC    U1002    Lost Communication with Gateway Module (Main Body)

for Preparation Click here


DESCRIPTION

  1. The main body ECU will store this DTC when no signals can be received from the ECUs that have been memorized as those that are connected to the CAN MS bus.
  2. When the main body ECU receives a response signal from the ECUs connected to the CAN MS bus, the main body ECU recognizes and memorizes that the ECU is connected to the CAN MS bus. Based on this memorized data, the main body ECU monitors for malfunctions in the ECUs connected to the CAN MS bus when communicating with those ECUs. If the main body ECU cannot receive response signals from the ECUs that have been memorized as those connected to the CAN MS bus, the main body ECU determines that a malfunction exists.

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.
  1. Open or short in CAN MS bus main line or connector
  2. Open or short in CAN MS bus branch line or connector
  3. Main body ECU (Multiplex network body ECU)
  4. Outer mirror control ECU assembly (Driver side)
  5. Outer mirror control ECU assembly (Front passenger side)
  6. Position control ECU and switch assembly
  7. CAN No. 6 junction connector

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


WIRING DIAGRAM


C236205E03


C236205E04


INSPECTION PROCEDURE

NOTICE:
  1. 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).
  2. Turn the power switch off before measuring the resistances between CAN main bus lines and between CAN branch lines.
  3. Turn the power switch off before inspecting CAN bus lines for a ground short.
  4. After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.
  5. 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.

HINT:
  1. 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.
  2. 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.

1.CHECK CAN MS BUS LINES

  1. Turn the power switch off.



    C236433E01

  1. 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

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

  1. 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

    Text in Illustration 
    *1
    		DLC3
    *a
    		Component with harness connected
    (CAN No. 6 Junction Connector)

    Result:
    Result
    		Proceed to
    OK
    		A
    Open circuit in CAN main bus line
    		B
    Short circuit between bus lines
    		C
    1. Ground short
    2. +B short
    		D



B
Go to step 3

C
Go to step 5

D
Go to step 9
A


2.RECONFIRM DTC OUTPUT (MAIN BODY ECU)

  1. Clear the DTCs.

  1. Turn the power switch off.

  1. 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



B
GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC
A

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

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


    C235315E01

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

  1. 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

    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to CAN No. 6 Junction Connector)



NG
Go to step 4
OK

REPLACE CAN NO. 6 JUNCTION CONNECTOR 

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.



    C204821E03

  1. Disconnect the main body ECU connector.

  1. 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

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Main Body ECU (Multiplex Network Body ECU))



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

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

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


    C235315E01

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

  1. 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

    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to CAN No. 6 Junction Connector)



NG
Go to step 8
OK


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


    C235316E01

  1. Reconnect the main body ECU main line harness connector to the CAN No. 6 junction connector.
    Text in Illustration 
    *a
    		Component with harness connected
    (CAN No. 6 Junction Connector)

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



  1. 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).


    C235202E01


    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
    1. Outer mirror control ECU assembly (Front passenger side)*1
    2. 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
    1. Outer mirror control ECU assembly (Driver side)*1
    2. Outer mirror control ECU assembly (Front passenger side)*2
    H102-2 (CANL)
    		W
    1. *1: for LHD
    2. *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



B
Go to step 7
A

REPLACE CAN NO. 6 JUNCTION CONNECTOR 

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).

  1. Disconnect the connector that includes terminals CANH and CANL from the ECU to which the short-circuited branch line is connected.



    C235316E01

  1. 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

    Text in Illustration 
    *a
    		Component with harness connected
    (CAN No. 6 Junction Connector)

    HINT:
    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.



NG
REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINE OR CONNECTOR
OK

REPLACE CORRESPONDING ECU OR SWITCH 

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.



    C204821E03

  1. Disconnect the main body ECU connector.

  1. 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

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Main Body ECU (Multiplex Network Body ECU))



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

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

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


    C236584E01

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

  1. 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

    Text in Illustration 
    *1
    		DLC3
    *a
    		Rear view of wire harness connector
    (to CAN No. 6 Junction Connector)

    HINT:
    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
Go to step 12
OK


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


    C236433E01

  1. Reconnect the main body ECU main line harness connector to the CAN No. 6 junction connector.
    Text in Illustration 
    *1
    		DLC3
    *a
    		Component with harness connected
    (CAN No. 6 Junction Connector)

  1. 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.

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



  1. 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)).


    C235202E01


    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
    1. Outer mirror control ECU assembly (Front passenger side)*1
    2. 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
    1. Outer mirror control ECU assembly (Driver side)*1
    2. Outer mirror control ECU assembly (Front passenger side)*2
    H102-2 (CANL)
    		W
    1. *1: for LHD
    2. *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.)



B
Go to step 11
A

REPLACE CAN NO. 6 JUNCTION CONNECTOR 

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).

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



    C236433E01

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

    HINT:
    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

    Text in Illustration 
    *1
    		DLC3
    *a
    		Component with harness connected
    (CAN No. 6 Junction Connector)

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



NG
REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINE OR CONNECTOR
OK

REPLACE CORRESPONDING ECU OR SWITCH 

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

  1. Disconnect the main body ECU connector.



    C236438E01

  1. 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

    HINT:
    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.

    Text in Illustration 
    *1
    		DLC3
    *a
    		Rear view of wire harness connector
    (to CAN No. 6 Junction Connector)



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

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