UART Communication Line Circuit Inspection

CHECK UART LINE HARNESS
1. Disconnect driver seat control unit connector and automatic drive positioner control unit connector.
2. Check continuity between driver seat control unit connector B152 terminal 2 (P), 8 (G/Y) and automatic drive positioner connector M49 terminal 10 (B), 26 (G).
  2 (P) - 26 (G): Continuity should exist.
  
  8 (G/Y) - 10 (R): Continuity should exist.
3. Check continuity between driver seat control unit connector B152 terminal 2 (P), 8 (G/Y) and ground.
  2 (P) - Ground: Continuity should not exist.
  
  8 (G/Y) - Ground: Continuity should not exist.
  
  Fig 1: Checking UART Line Harness
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 2.
2. NG: Repair or replace harness between driver seat control unit and automatic drive positioner.
CHECK UART LINE INPUT/OUTPUT SIGNAL
1. Turn ignition switch ON. 1
2. Check signal between driver seat control unit connector ground, with oscilloscope.
  
  Fig 2: Checking UART Line Input/Output Signal (1 Of 2)
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Fig 3: Checking UART Line Input/Output Signal (2 Of 2)
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 3.
2. NG: Check the flowing.
  - When voltage waveform dose not appear with a constant voltage (approx. 5V), replace driver seat control unit.
  - When voltage waveform dose not appear with a constant voltage (approx. 0V), replace automatic drive positioner control unit.
CHECK UART LINE INPUT/OUTPUT SIGNAL 2
Check signal between automatic driver positioner control unit connector ground, with oscilloscope.

Fig 4: Checking UART Line Input/Output Signal 2 (1 Of 2)
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 5: Checking UART Line Input/Output Signal 2 (2 Of 2)
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG
1. OK: GO TO 4.
2. NG: Check the flowing.
  - When voltage waveform dose not appear with a constant voltage (approx. 5V), replace automatic driver seat control unit.
  - When voltage waveform dose not appear with a constant voltage (approx. 0V), replace driver seat control unit.
CHECK DRIVER SEAT CONTROL UNIT
Dose the automatic drive positioner operate, when the driver control unit exchanged?

Does horn operate?
1. YES: Replace automatic drive positioner control unit.
2. NG: Replace driver seat control unit.