DTC : B1142

DTC B1142  : Door multiplex control unit lost communication with front passenger's power window switch (UART line open)

DTC (Door Multiplex Control Unit)

NOTE:  If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Go to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks .

1. Problem verification

   -1. Clear the DTCs with the HDS.

   Clear DTCs

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

   - 3. Open and close all power windows by operating the power window master switch.

   - 4. Check for DTCs with the HDS.

   DTC Description	DTC
   B1142 Door multiplex control unit 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 (WINDOW) line) 1

   -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 24P connector

   Moonroof control unit/motor 14P 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 24P connector: disconnected Moonroof control unit/motor 14P connector: disconnected
   Test point 1	Power window master switch 37P connector No. 36 - Refer to: Power Window Master Switch Connector for Inputs and Outputs (2016 2017 2018) or Power Window Master Switch Connector for Inputs and Outputs (2019 2020 2021) .
   Test point 2	Front Passenger's Power Window Switch 24P Connector No. 24

   Is there continuity?

   YES 

   The LIN (WINDOW) wire is not open between power window master switch and front passenger's power window switch. Go to step 3.

   NO 

   Repair an open or high resistance in the wire.

3. Open wire check (LIN (WINDOW) line) 4

   -1. 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 24P connector: disconnected Moonroof control unit/motor 14P connector: disconnected
   Test point 1	Power window master switch 37P connector No. 36 - Refer to: Power Window Master Switch Connector for Inputs and Outputs (2016 2017 2018) or Power Window Master Switch Connector for Inputs and Outputs (2019 2020 2021) .
   Test point 2	Moonroof Control Unit/Motor 14P Connector No. 12

   Is there continuity?

   YES 

   The LIN (WINDOW) wire is not open between power window master switch and moonroof control unit/motor. Go to step 4.

   NO 

   Repair an open or high resistance in the wire.

4. Shorted wire check (LIN (WINDOW) line)

   -1. 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 24P connector: disconnected Moonroof control unit/motor 14P connector: disconnected
   Test point 1	Power window master switch 37P connector No. 36 - Refer to: Power Window Master Switch Connector for Inputs and Outputs (2016 2017 2018) or Power Window Master Switch Connector for Inputs and Outputs (2019 2020 2021) .
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to ground in the wire.

   NO 

   The LIN (WINDOW) wire is not shorted to ground. Go to step 5.

5. Shorted wire check (LIN (WINDOW) line to power)

   -1. Turn the vehicle to the ON mode.

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

   Test condition	Vehicle ON mode Power window master switch 37P connector: disconnected Front passenger's power window switch 24P connector: disconnected Moonroof control unit/motor 14P connector: disconnected
   Test point 1	Power window master switch 37P connector No. 36 - Refer to: Power Window Master Switch Connector for Inputs and Outputs (2016 2017 2018) or Power Window Master Switch Connector for Inputs and Outputs (2019 2020 2021) .
   Test point 2	Body ground

   Is there less than 0.2 V?

   YES 

   The LIN (WINDOW) wire is OK. Go to the front passenger's Power Window Switch Input Test , and do the power and ground input tests.

   If the tests prove OK, substitute a known good front passenger's power window switch.

   If the DTC goes away, replace the original front passenger's Power Window Switch - Removal and Installation .

   If the DTC is still present, replace the Power Window Master Switch - Removal and Installation .

   NO 

   Repair a short to power in the wire.