DTC B1142

DTC B1142  : Power Window Master Switch lost communication with the other units (UART communication error)

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

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 the other units (UART communication error)

   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 *: disconnected

   *: With moonroof

   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*	No. 12

   *: With moonroof

   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.

   -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.

      • Front passenger's power window switch
      • Moonroof motor-control unit*

      *: With moonroof

      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 *: disconnected
   Test point 1	Power window master switch 37P connector No. 36
   Test point 2	Body ground

   *: With moonroof

   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:

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

   • Front passenger's power window

   -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.

   • Front passenger's power window switch
   • Mooroof motor-control unit*

   *: With moonroof