Communication Line Check (Between NAVI Control Unit and Display Unit)

WARNING: This page is about a different car, the 2004 Infiniti G35. However, it is still accessible from the selected car via links, so may be relevant.

CHECK HARNESS
1. Turn ignition switch OFF.
2. Disconnect NAVI control unit connector and display unit connector.
3. Check continuity between NAVI control unit harness connector M58 terminal 35 (B), 31 and display unit harness connector M35 terminal 14 (B), 15.
  Continuity should exist.
4. Check continuity between NAVI control unit harness connector M58 terminal 35 (B), 31 and ground.
  Continuity should not exist.
  
  Fig 1: Checking Continuity Between NAVI Control Unit Harness Connector M58 Terminal 35 (B), 31 And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 2.
2. NG: Repair harness or connector.
COMMUNICATION SIGNAL CHECK
1. Connect NAVI control unit connector.
2. Turn ignition switch ON
3. Check voltage between NAVI control unit harness connector M58 terminal 35 (B) and 31.
  35 (B) - 31: Approx 5V
OK or NG
1. OK: Replace display unit.
2. NG: Replace NAVI control unit.
  
  Fig 2: Checking Voltage Between NAVI Control Unit Harness Connector M58 Terminal 35 (B) And 31
  Courtesy of NISSAN MOTOR CO., U.S.A.