DTC Troubleshooting: B1142

DTC B1142: Power Window Master Switch Lost Communication With the Other Units(UART communication Error)

DTC Description	DTC
B1142 Power window master switch lost communication with the other units(UART communication Error)

Problem verification:

Problem verification

?1.	Clear the DTCs with the HDS.

?2.	Turn the ignition switch to LOCK (0) and then back to ON (II), or press the engine start/stop button to select the OFF 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 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.?

Open wire check (LIN (P/W) line) 1:

Open wire check (LIN (P/W) line) 1

?1.	Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.

Disconnect the following connectors.

Power window master switch 37P connector
Front passenger's power window switch 37P connector
Moonroof control unit/motor 14P connector

?3.

Check for continuity between test points 1 and 2.

Test condition	IG LOCK (0) or OFF mode Power window master switch 37P connector: disconnected Front passenger's power window switch 37P connector: disconnected Moonroof control unit/motor 14P connector: disconnected
Test circuit	LIN (P/W)
Test point 1	Power window master switch 37P connector No. 36 (LT BLU)
Test point 2	Front passenger's power window switch 37P connector No. 34 (LT BLU)

Is there continuity?


	YES

The LIN (P/W) 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.?

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

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

?1.

Check for continuity between test points 1 and 2.

Test condition	IG LOCK (0) or OFF mode Power window master switch 37P connector: disconnected Front passenger's power window switch 37P connector: disconnected Moonroof control unit/motor 14P connector: disconnected
Test circuit	LIN (P/W)
Test point 1	Power window master switch 37P connector No. 36 (LT BLU)
Test point 2	Moonroof control unit/motor 14P connector No. 12 (LT BLU)

Is there continuity?


	YES

The LIN (P/W) 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.?

Shorted wire check (LIN (P/W) line):

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

?1.

Check for continuity between test points 1 and 2.

Test condition	IG LOCK (0) or OFF mode Power window master switch 37P connector: disconnected Front passenger's power window switch 37P connector: disconnected Moonroof control unit/motor 14P connector: disconnected
Test circuit	LIN (P/W)
Test point 1	Power window master switch 37P connector No. 36 (LT BLU)
Test point 2	Body ground

Is there continuity?


	YES

Repair a short to ground in the wire.?


	NO

The LIN (P/W) wire is not shorted to ground. Go to step 5.

Shorted wire check (LIN (P/W) line to power):

Shorted wire check (LIN (P/W) line to power)

?1.	Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?2.

Measure the voltage between test points 1 and 2.

Test condition	IG ON (II) or ON mode Power window master switch 37P connector: disconnected Front passenger's power window switch 37P connector: disconnected Moonroof control unit/motor 14P connector: disconnected
Test circuit	LIN (P/W)
Test point 1	Power window master switch 37P connector No. 36 (LT BLU)
Test point 2	Body ground

Is there less than 0.2 V?


	YES

The LIN (P/W) 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. If the DTC is still present, replace the power window master switch.?


	NO

Repair a short to power in the wire.?