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 (Multiplex Control Unit, Door)

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. Measure the resistance 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	Front passenger's power window switch 37P connector No. 34

   Test point 1	Power window master switch 37P connector No. 36
   Test point 2	Moonroof motor-control unit 14P connector No. 12 (with moonroof)

   Is there 1.0 Ω or less?

   YES 

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

   NO 

   Repair an open or high resistance in the wire.

3. Shorted wire check (LIN (P/W) line)

   -1. Measure the resistance 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 1.0 MΩ or more?

   YES 

   The LIN (P/W) wire is not shorted to ground. Go to step 4.

   NO 

   Repair a short to ground in the wire.

4. Shorted wire check (LIN (P/W) 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 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 less than 0.2 V?

   YES 

   The LIN(P/W) wire is OK. Do the input test for terminals of the front passenger's power window switch . 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 . If the DTC is still present, replace the power window master switch .

   NO 

   Repair a short to power in the wire.