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DTC B1142

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DTC B1142  : Power Window Master Switch Lost Communication with Front Passenger's Power Window Switch (UART Line Open)

NOTE:  If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A .

DTC Description DTC
B1142 Power window master switch lost communication with front passenger's power window switch (UART line open)  

DTC (Door Multiplex Control Unit)

  1. Problem verification

    -1. Clear the DTCs with the HDS.

    -2. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

    -3. Check for DTCs with the HDS.

    DTC Description DTC
    B1142 Power window master switch lost communication with front passenger's power window switch (UART line open)  

    Is DTC B1142 indicated?

    YES 

    Go to step 2.

    NO 

    Intermittent failure, the system is OK at this time.

  2. Open wire check (LIN (P/W) line)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the following connectors.

    Power window master switch 37P connector
    Front passenger's power window switch 37P connector
    Moonroof motor-control unit 14P connector (with moonroof)

    -3. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    Power window master switch 37P connector: disconnected
    Front passenger's power window switch 37P connector: disconnected
    Moonroof motor-control unit 14P connector (with moonroof): disconnected
    Test point 1 Test point 2
    Connector Terminal Connector Terminal
    Power window master switch 37P connector No. 36 Front passenger's power window switch 37P connector No. 34
    Power window master switch 37P connector No. 36 Moonroof motor-control unit 14P connector (with moonroof) No. 12

    Is there continuity?

    YES 

    The LIN (P/W) wire is not open. Go to step 3.

    NO 

    Repair an open or high resistance in the wire.

  3. Determine possible failure area (LIN (P/W) line, others)

    -1. Reconnect all the connectors.

    Power window master switch 37P connector
    Front passenger's power window switch 37P connector
    Moonroof motor-control unit 14P connector (with moonroof)

    -2. Turn the vehicle to the ON mode.

    -3. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
    Test point 1 Power window master switch 37P connector No. 36
    Test point 2 Body ground

    Is there less than 0.2 V?

    YES 

    Go to step 4.

    NO 

    Go to step 6.

  4. Shorted wire check (LIN (P/W) line) 1

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the appropriate connector at each switch and control unit in the table one at a time.

    Connector
    Front passenger's power window switch 37P connector
    Moonroof motor-control unit 14P connector (with moonroof)

    -3. Turn the vehicle to the ON mode.

    -4. Measure the voltage between test points 1 and 2.

    Test condition Vehicle ON mode
    Test point 1 Power window master switch 37P connector No. 36
    Test point 2 Body ground

    Is there battery voltage?

    1. YES 

      Internal circuit short. Replace the faulty switch or unit.

      NO 

      Go to step 5.

  5. Shorted wire check (LIN (P/W) line) 2

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Disconnect the following connector.

    Power window master switch 37P connector

    -3. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
    Power window master switch 37P connector: disconnected
    Front passenger's power window switch 37P connector: disconnected
    Moonroof motor-control unit 14P connector (with moonroof): disconnected
    Test point 1 Power window master switch 37P connector No. 36
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short to ground in the wire.

    NO 

    Power window master switch internal circuit short. Replace the power window master switch .

  6. Switch or unit check

    -1. Open and close the front passenger's power window by operating the power window master switch.

    -2. With moonroof: Open and close the moonroof by operating the moonroof switch.

    Do the switches or unit work normally?

    YES 

    Replace the power window master switch .

    NO 

    Replace the faulty switch or unit.