Vehicle Speed Signal Check for Display Control Unit

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

CHECK HARNESS
1. Turn ignition switch OFF.
2. Disconnect display control unit connector and combination meter connector.
3. Check continuity between display control unit harness connector M94 terminal 16 (P/L) and combination meter harness connector M24 terminal 14 (P/L).
  1. Continuity should exist.
4. Check continuity between display control unit harness connector M94 terminal 16 (P/L) and ground.
  1. Continuity should not exist.
  OK or NG
  1. OK: GO TO 2.
  2. NG: Repair harness.
    
    Fig 1: Checking Continuity Between Display Control Unit Harness Connector M94 Terminal 16 (P/L) And Ground
    Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK 1: VEHICLE SPEED SIGNAL
1. Connect display control unit connector and combination meter connector.
2. Turn ignition switch ON.
3. Check voltage between display control unit harness connector M94 terminal 16 (P/L) and ground.
Approx. 3.5V or more

OK or NG
1. OK: GO TO 3.
2. NG: Replace display control unit. Refer to REMOVAL AND INSTALLATION OF DISPLAY CONTROL UNIT .
  
  Fig 2: Checking Voltage Between Display Control Unit Harness Connector M94 Terminal 16 (P/L) And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK 2: VEHICLE SPEED SIGNAL
1. Drive vehicle at a constant speed.
2. Check signal between display control unit harness connector M94 terminal 16 (P/L) and ground with CONSULT-II or oscilloscope.
1. 16 (P/L) - Ground: Refer to TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT .
OK or NG
1. OK: Replace display control unit. Refer to REMOVAL AND INSTALLATION OF DISPLAY CONTROL UNIT .
2. NG: Check combination meter system. Refer to VEHICLE SPEED SIGNAL INSPECTION .
  
  Fig 3: Checking Signal Between Display Control Unit Harness Connector M94 Terminal 16 (P/L) And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.