Audio Communication Line Check (Between Display Control Unit and Audio Unit

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

CHECK POWER SUPPLY AND GROUND CIRCUIT
1. Check system of power supply and ground circuit audio unit. Refer to POWER SUPPLY CIRCUIT INSPECTION
OK or NG
1. OK : GO TO 2.
2. NG : Check the malfunctioning parts.

CHECK HARNESS

Turn ignition switch OFF.
Disconnect audio unit connector and display control unit connector.

Check continuity between audio unit and display control unit.

AUDIO UNIT AND DISPLAY CONTROL UNIT TERMINALS CONTINUITY

Terminals				Continuity
Display control unit		Audio unit
Connector	Terminal (Wire color)	Connector	Terminal (Wire color)
M95	40 (O/L)	M45	65 (O/L)	Yes
	42 (W/L)		66 (W/L)

Check continuity between display control unit and ground.

DISPLAY CONTROL UNIT TERMINALS CONTINUITY

Terminals			Continuity
Display control unit		---
Connector	Terminal (Wire color)
M95	40 (O/L)	Ground	No
	42 (W/L)

Fig 1: Checking Continuity Between Display Control Unit Terminals And Ground

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

OK or NG

OK : GO TO 3.
NG : Repair harness or connector.

CHECK 1: AUDIO-TX COMMUNICATION SIGNAL
1. Connect display control unit connector.
2. Turn ignition switch ON.
3. Check voltage between display control unit harness connector M95 terminal 42 (W/L) and ground.
  Approx. 3.5 V or more.
  
  Fig 2: Checking Voltage Between Display Control Unit Harness Connector M95 Terminal 42 (W/L) And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK : GO TO 4.
2. NG : Replace display control unit. Refer to , "REMOVAL AND INSTALLATION OF DISPLAY CONTROL UNIT ".
CHECK 2: AUDIO-RX COMMUNICATION SIGNAL
1. Turn ignition switch OFF.
2. Disconnect display control unit connector.
3. Connect audio unit connector.
4. Turn ignition switch ON.
5. Check voltage between audio unit harness connector M45 terminal 65 (O/L) and ground.
  Approx. 3.5 V or more.
  
  Fig 3: Checking Voltage Between Audio Unit Harness Connector M45 Terminal 65 (O/L) And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK : GO TO 5.
2. NG : Replace audio unit. Refer to REMOVAL AND INSTALLATION FOR AUDIO UNIT
CHECK 3: AUDIO-TX COMMUNICATION SIGNAL
1. Turn ignition switch OFF.
2. Connect display control unit connector.
3. Turn ignition switch ON.
4. Check signal between display control unit harness connector M95 terminal 40 (O/L) and ground with CONSULT-II or oscilloscope.
  40 (O/L) - Ground: Refer to , "TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT ".
  
  Fig 4: Checking Signal Between Display Control Unit Harness Connector M95 Terminal 40 (O/L) And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK : GO TO 6.
2. NG : Replace display control unit. Refer to , "REMOVAL AND INSTALLATION OF DISPLAY CONTROL UNIT ".
CHECK 4: AUDIO-RX COMMUNICATION SIGNAL
1. Turn ignition switch ON.
2. Check signal between display control unit harness connector M95 terminal 42 (W/L) and ground with CONSULT-II or oscilloscope.
  42 (W/L) - Ground : Refer to , "TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT ".
  
  Fig 5: Checking Signal Between Display Control Unit Harness Connector M95 Terminal 42 (W/L) And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK : INSPECTION END.
2. NG : Replace audio unit. Refer to REMOVAL AND INSTALLATION FOR AUDIO UNIT