UART Communication Line Circuit Check

1. Turn ignition switch OFF.
2. Disconnect driver seat control unit and automatic drive positioner control unit connector.
3. Check continuity between driver seat control unit connector and automatic drive positioner connector.
   DRIVER SEAT CONTROL UNIT CONNECTOR AND AUTOMATIC DRIVE POSITIONER CONNECTOR CONTINUITY
   
   

   A		B		Continuity
   Driver seat control unit connector	Terminal	Automatic drive positioner control unit connector	Terminal
   B204	1	M6	10	Yes
   	17		26

4. Check continuity between driver seat control unit connector and ground.
   DRIVER SEAT CONTROL UNIT CONNECTOR AND GROUND CONTINUITY
   
   

   A		Ground	Continuity
   Driver seat control unit connector	Terminal
   B204	1		No
   	17

   Fig 1: Identifying Continuity Between Driver Seat Control Unit Connector And Automatic Drive Positioner Connector

   Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG 

OK: GO TO 2.

NG: Repair or replace harness.

1. Connect driver seat control unit and automatic drive positioner control unit connector.
2. Turn ignition switch ON.
3. Check signal between driver seat control unit connector and ground, with oscilloscope.

Driver seat control unit connector	Terminals		Condition	Signal (Reference value)
	(+)	(-)
B204	17	Ground	Tilt switch operated

Fig 2: Identifying Signal Between Driver Seat Control Unit Connector And Ground, With Oscilloscope

Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG 

OK: GO TO 3.

NG: Check the following.

• When voltage wave form does not appear with a constant voltage (approx. 5V), replace driver seat control unit.
• When voltage wave form does not appear with a constant voltage (approx. 0V), replace automatic drive positioner control unit.

Check signal between automatic drive positioner control unit connector and ground, with oscilloscope.

Automatic drive positioner control unit connector	Terminals		Condition	Signal (Reference value)
	(+)	(-)
M6	10	Ground	Tilt switch operated.

Fig 3: Identifying Signal Between Automatic Drive Positioner Control Unit Connector And Ground, With Oscilloscope

Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG 

OK: GO TO 4.

NG: Check the following.

• When voltage wave form does not appear with a constant voltage (approx. 5V), replace automatic drive positioner control unit.
• When voltage wave form does not appear with a constant voltage (approx. 0V), replace driver seat control unit.

Does the automatic drive positioner operate when the driver seat control unit is exchanged?

OK or NG 

OK: Replace driver seat control unit.

NG: Replace automatic drive positioner control unit.