DTC    U1002    Lost Communication with Gateway Module (Power Management1)

for Preparation Click here


DESCRIPTION

  1. The power management control 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 V2 bus.
  2. When the power management control ECU receives a response signal from the ECUs connected to the V2 bus, the power management control ECU recognizes and memorizes that the ECU is connected to the V2 bus. Based on this memorized data, the power management control ECU monitors for malfunctions in the ECUs connected to the V2 bus when communicating with those ECUs. If the power management control ECU cannot receive response signals from the ECUs that have been memorized as those connected to the V2 bus, the power management control ECU determines that a malfunction exists.

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 the V2 bus.
  1. Open or short in V2 bus main line or connector
  2. Open or short in V2 bus branch line or connector
  3. Power management control ECU
  4. Driving support ECU assembly
  5. Seat belt control ECU
  6. Parking assist ECU
  7. Clearance warning ECU assembly
  8. CAN No. 4 junction connector

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


WIRING DIAGRAM


C236202E02


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 V2 BUS LINES

  1. Turn the power switch off.



    C235176E03

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    		Result
    H3-34 (CA2H) - H3-35 (CA2L)
    		Power switch off
    		54 to 69 Ω
    		Below 54 Ω:
    Short circuit between bus lines
    70 Ω or higher:
    Open circuit in a main bus line
    H3-34 (CA2H) - H3-6 (E1)
    		Power switch off
    		200 Ω or higher
    		Below 200 Ω:
    CANH ground short
    H3-35 (CA2L) - H3-6 (E1)
    		Power switch off
    		200 Ω or higher
    		Below 200 Ω:
    CANL ground short

    Text in Illustration 
    *a
    		Component with harness connected
    (Power Management Control ECU)

  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
    H3-34 (CA2H) - H3-1 (AM22)
    		Cable disconnected from negative (-) auxiliary battery terminal
    		6 kΩ or higher
    		Below 6 kΩ:
    CANH +B short
    H3-35 (CA2L) - H3-1 (AM22)
    		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
    1. Ground short
    2. +B short
    		D



B
Go to step 3

C
Go to step 5

D
Go to step 9
A


2.CHECK DTC OUTPUT

  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 power management control ECU
    (Intelligent tester display/ PM1 Gateway)
    		A
    Other DTC is output
    		B



B
GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC
A

REPLACE POWER MANAGEMENT CONTROL ECU (Click here)  

3.CHECK FOR OPEN IN V2 BUS MAIN LINES (POWER MANAGEMENT CONTROL ECU MAIN WIRE)


    A204445E30

  1. Disconnect the power management control ECU connector.

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    H3-34 (CA2H) - H3-35 (CA2L)
    		Power switch off
    		108 to 132 Ω

    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to Power Management Control ECU)



NG
Go to step 4
OK

REPLACE POWER MANAGEMENT CONTROL ECU (Click here)  

4.CHECK FOR OPEN IN V2 BUS MAIN LINES (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)

  1. Reconnect the power management control ECU connector.



    C189424E31

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

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    		Connected to
    H106-1 (CANH) - H106-2 (CANL)
    		Power switch off
    		108 to 132 Ω
    		Power management control ECU

    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to CAN No. 4 Junction Connector)
    *b
    		to Power Management Control ECU



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

REPLACE CAN NO. 4 JUNCTION CONNECTOR 

5.CHECK FOR SHORT IN V2 BUS LINES (POWER MANAGEMENT CONTROL ECU)


    A204445E30

  1. Disconnect the power management control ECU connector.

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    H3-34 (CA2H) - H3-35 (CA2L)
    		Power switch off
    		108 to 132 Ω

    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to Power Management Control ECU)



NG
Go to step 6
OK

REPLACE POWER MANAGEMENT CONTROL ECU (Click here)  

6.CHECK FOR SHORT IN V2 BUS LINES (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)

  1. Reconnect the power management control ECU connector.



    C189424E31

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

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    		Connected to
    H106-1 (CANH) - H106-2 (CANL)
    		Power switch off
    		108 to 132 Ω
    		Power management control ECU

    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to CAN No. 4 Junction Connector)
    *b
    		to Power Management Control ECU



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


7.CHECK FOR SHORT IN V2 BUS LINES (CAN NO. 4 J/C)

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



    C235176E02

  1. Connect the probes of an ohmmeter to terminals 34 (CA2H) and 35 (CA2L) of the power management control ECU.
    Text in Illustration 
    *a
    		Component with harness connector
    (Power Management Control ECU)



  1. While observing the resistance value shown on the ohmmeter, disconnect branch line connectors (except H106) from the CAN No. 4 junction connector until the resistance becomes normal (between 54 and 69 Ω).


    C235178E01


    Text in Illustration 
    *1
    		CAN No. 4 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. 4 Junction Connector)

    Junction Connector B Side 
    Terminal No. (Symbol)
    		Wiring Color
    		Connected to
    H110-1 (CANH)
    		P
    		Parking assist ECU
    H110-2 (CANL)
    		B

    Junction Connector A Side 
    Terminal No. (Symbol)
    		Wiring Color
    		Connected to
    H111-1 (GND)
    		W-B
    		Body ground
    H106-1 (CANH)
    		R
    		Power management control ECU
    H106-2 (CANL)
    		B
    H107-1 (CANH)
    		G
    		Clearance warning ECU assembly
    H107-2 (CANL)
    		B
    H108-1 (CANH)
    		L
    		Driving support ECU assembly
    H108-2 (CANL)
    		B
    H109-1 (CANH)
    		Y
    		Seat belt control ECU
    H109-2 (CANL)
    		B

    HINT:
    1. The connectors connected to the CAN junction connector can be distinguished by the colors of the bus line.
    2. Reconnecting the connectors to non-specified positions on the CAN junction connector does not affect system operation.

      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



B
Go to step 8
A

REPLACE CAN NO. 4 JUNCTION CONNECTOR 

8.CHECK FOR SHORT IN V2 BUS 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).

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



    C235176E02

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    H3-34 (CA2H) - H3-35 (CA2L)
    		Power switch off
    		54 to 69 Ω

    Text in Illustration 
    *a
    		Component with harness connector
    (Power Management Control ECU)

    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 SENSOR 

9.CHECK FOR SHORT IN V2 BUS LINE (POWER MANAGEMENT CONTROL ECU)


    A204445E31

  1. Disconnect the power management control ECU connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    		Purpose
    H3-34 (CA2H) - H3-6 (E1)
    		Power switch off
    		200 Ω or higher
    		Inspection for CANH ground short
    H3-35 (CA2L) - H3-6 (E1)
    		Power switch off
    		200 Ω or higher
    		Inspection for CANL ground short
    H3-34 (CA2H) - H3-1 (AM22)
    		Cable disconnected from negative (-) auxiliary battery terminal
    		6 kΩ or higher
    		Inspection for CANH +B short
    H3-35 (CA2L) - H3-1 (AM22)
    		Cable disconnected from negative (-) auxiliary battery terminal
    		6 kΩ or higher
    		Inspection for CANL +B short

    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to Power Management Control ECU)

    HINT:
    It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check V2 Bus Line inspection.
    Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check V2 Bus Line inspection.



NG
Go to step 10
OK

REPLACE POWER MANAGEMENT CONTROL ECU (Click here)  

10.CHECK FOR SHORT IN V2 BUS LINE (CAN NO. 4 J/C - POWER MANAGEMENT CONTROL ECU)


    C189424E31

  1. Disconnect the power management control ECU main line connector from the CAN No. 4 junction connector.
    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to CAN No. 4 Junction Connector)
    *b
    		to Power Management Control ECU



    A204445E31

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    		Purpose
    H3-34 (CA2H) - H3-6 (E1)
    		Power switch off
    		200 Ω or higher
    		Inspection for CANH ground short
    H3-35 (CA2L) - H3-6 (E1)
    		Power switch off
    		200 Ω or higher
    		Inspection for CANL ground short
    H3-34 (CA2H) - H3-1 (AM22)
    		Cable disconnected from negative (-) auxiliary battery terminal
    		6 kΩ or higher
    		Inspection for CANH +B short
    H3-35 (CA2L) - H3-1 (AM22)
    		Cable disconnected from negative (-) auxiliary battery terminal
    		6 kΩ or higher
    		Inspection for CANL +B short

    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to Power Management Control ECU)

    HINT:
    It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check V2 Bus Line inspection.
    Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check V2 Bus Line inspection.



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


11.CHECK FOR SHORT IN V2 BUS LINE (CAN NO. 4 J/C)

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



    A204445E31

  1. Connect the probes of an ohmmeter to terminals CANH or CANL and GND or +B (AM22) of the power management control ECU.
    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to Power Management Control ECU)

    HINT:
    It is only necessary to perform the inspection for the result (short circuit) that was obtained in the Check V2 Bus Line inspection.



  1. While observing the resistance value shown on the ohmmeter, disconnect branch line connectors (except H106) 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)).


    C235178E01


    Text in Illustration 
    *1
    		CAN No. 4 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. 4 Junction Connector)

    Junction Connector B Side 
    Terminal No. (Symbol)
    		Wiring Color
    		Connected to
    H110-1 (CANH)
    		P
    		Parking assist ECU
    H110-2 (CANL)
    		B

    Junction Connector A Side 
    Terminal No. (Symbol)
    		Wiring Color
    		Connected to
    H111-1 (GND)
    		W-B
    		Body ground
    H106-1 (CANH)
    		R
    		Power management control ECU
    H106-2 (CANL)
    		B
    H107-1 (CANH)
    		G
    		Clearance warning ECU assembly
    H107-2 (CANL)
    		B
    H108-1 (CANH)
    		L
    		Driving support ECU assembly
    H108-2 (CANL)
    		B
    H109-1 (CANH)
    		Y
    		Seat belt control ECU
    H109-2 (CANL)
    		B

    HINT:
    1. The connectors connected to the CAN junction connector can be distinguished by the colors of the bus line.
    2. Reconnecting the connectors to non-specified positions on the CAN junction connector does not affect system operation.

      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.)



B
Go to step 12
A

REPLACE CAN NO. 4 JUNCTION CONNECTOR 

12.CHECK FOR SHORT IN V2 BUS 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).

  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.



    A204445E31

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    		Purpose
    H3-34 (CA2H) - H3-6 (E1)
    		Power switch off
    		200 Ω or higher
    		Inspection for CANH ground short
    H3-35 (CA2L) - H3-6 (E1)
    		Power switch off
    		200 Ω or higher
    		Inspection for CANL ground short
    H3-34 (CA2H) - H3-1 (AM22)
    		Cable disconnected from negative (-) auxiliary battery terminal
    		6 kΩ or higher
    		Inspection for CANH +B short
    H3-35 (CA2L) - H3-1 (AM22)
    		Cable disconnected from negative (-) auxiliary battery terminal
    		6 kΩ or higher
    		Inspection for CANL +B short

    Text in Illustration 
    *a
    		Rear view of wire harness connector
    (to Power Management Control ECU)

    HINT:
    It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check V2 Bus Line inspection.
    Find the necessary inspection from the Purpose column that matches the result in the Result column from the Check V2 Bus Line inspection.



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

REPLACE CORRESPONDING ECU OR SENSOR