UART Communication Line Circuit Inspection

WARNING: This page is about a different car, the 2004 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.

CHECK UART LINE HARNESS
1. Turn ignition switch OFF.
2. Disconnect driver seat control unit and automatic drive positioner control unit.
3. Check continuity between driver seat control unit connector P2 terminal 1, 17 and automatic drive positioner connector M41 terminal 10, 26.
  1 (W/B) - 10 (R): Continuity should exist.
  
  17 (GR) - 26 (R/W): Continuity should exist.
4. Check continuity between driver seat control unit connector P2 terminal 1, 17 and ground.
  
  Fig 1: Checking UART Line Harness
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  1 (W/B) - Ground: Continuity should not exist.
  
  17 (GR) - Ground: Continuity should not exist.
OK or NG
- OK: GO TO 2.
- NG: Repair or replace harness.
CHECK UART LINE INPUT/OUTPUT SIGNAL 1
Check signal between driver seat control unit connector and ground, with oscilloscope.

Fig 2: Signal Reference Chart
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 3: Checking Signal Between Driver Seat Control Unit Connector And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG
- OK: GO TO 3.
- NG: Replace driver seat control unit.
CHECK UART LINE INPUT/OUTPUT SIGNAL 2
Check signal between automatic driver positioner control unit connector ground, with oscilloscope.

Fig 4: Signal Reference Chart
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 5: Checking Signal Between Automatic Driver Positioner Control Unit Connector Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG
- OK: GO TO 4.
- NG: Replace automatic driver positioner control unit.
CHECK DRIVER SEAT CONTROL UNIT
Does the automatic drive positioner function when the driver control unit is exchanged?

OK or NG
- OK: Replace driver seat control unit.
- NG: Replace automatic drive positioner control unit.