DTC B1142: Door Multiplex Control Unit Lost Communication with Front Passenger's Power Window Switch (UART Line Open)

WARNING: This page is about a different car, the 2011 Acura TL, 2010 Acura TL, and 2009 Acura TL. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A )
Before troubleshooting, check the No 16 (7 5 A), No 13 (20 A) and No 24 (20 A) fuses in the driver's under-dash fuse/relay box

Clear the DTCs with the HDS
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
Open and close all power windows by using the power window master switch
Check for DTCs with the HDS
Is DTC B1142 indicated?

YES -Go to step 5

NO -Intermittent failure, the system is OK at this time Check for loose or poor connections
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
Disconnect the door multiplex control unit 37P connector
Disconnect the moonroof control unit 14P connector
Check for continuity between power window master switch 37P connector terminal No 27 and moonroof control unit 14P connector terminal No 11

Fig 1: Checking Continuity Between Power Window Master Switch 37P Connector Terminals And Moonroof Control Unit 14P Connector Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 9

NO -Repair open in the wire
Disconnect the front passenger's power window switch 37P connector
Check for continuity between door multiplex control unit 37P connector terminal No 27 and front passenger's power window switch 37P connector terminal No 29

Fig 2: Checking Continuity Between Door Multiplex Control Unit 37P And Front Passenger's Power Window Switch 37P Connector Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 11

NO -Repair open in the wire
Check for continuity between door multiplex control unit 37P connector terminal No 27 and body ground

Fig 3: Checking Continuity Between Door Multiplex Control Unit 37P Connector Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair short to ground in PNK wire

NO -Go to step 12
Reconnect the door multiplex control unit 37P connector
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
Measure the voltage between door multiplex control unit 37P connector terminal No 27 and body ground

Fig 4: Measuring Voltage Between Door Multiplex Control Unit 37P Connector Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there less than 0 2V

YES -Substitute a known-good power window master switch, then reset the power window control unit and recheck If the DTC goes away, replace the original power window master switch (see REAR POWER WINDOW SWITCH TEST ) If the DTC is still present, substitute a known-good passenger's power window switch, and recheck If the DTC is still present, replace the moonroof control unit (see MOTOR REPLACEMENT )

NO -Repair short to power in the wire