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

WARNING: This page is about a different car, the 2004 Nissan Murano. 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 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.

CONTINUITY CHECK CHART

Terminals				Continuity
Display control unit		Audio unit
Connector	Terminal (Wire color)	Connector	Terminal (Wire color)
M43	40 (R/G)	M46	23 (R/G)	Yes
M43	42 (R/Y)	M46	21 (R/Y)	Yes

Check continuity between display control unit and ground.

CONTINUITY CHECK CHART

Terminals
	Display control unit		Ground
Connector	Terminal (Wire color)
M43	40 (R/G)	No
M43	42 (R/Y)	No

Fig 1: Checking Continuity Between Display Control Unit And Ground

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

OK or NG

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

CHECK1: AUDIO TX COMMUNICATION SIGNAL
1. Connect audio unit connector.
2. Turn ignition switch ON.
3. Check voltage between audio unit harness connector M46 terminal 23 (R/G) and ground.
  Approx. 4V
  
  Fig 2: Checking Voltage Between Audio Unit Harness Connector And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 4.
2. NG: Replace audio unit.
CHECK2: AUDIO RX COMMUNICATION SIGNAL
1. Turn ignition switch OFF.
2. Disconnect audio unit connector, and connect display control unit connector.
3. Turn ignition switch ON.
4. Check voltage between display control unit harness connector M43 terminal 42 (R/Y) and ground.
  Approx. 4V
  
  Fig 3: Checking Voltage Between Display Control Unit Harness Connector And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 5.
2. NG: Replace display control unit.
CHECK3: AUDIO TX COMMUNICATION SIGNAL
1. Turn ignition switch OFF.
2. Connect audio unit connector.
3. Turn ignition switch ON.
4. Check signal between display control unit harness connector M43 terminal 40 (R/G) and ground with CONSULT-II or oscilloscope.
  40 (R/G) - Ground: Refer to " TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT ".
  
  Fig 4: Checking Signal Between Display Control Unit Harness Connector And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 6.
2. NG: Replace display control unit.
CHECK4: AUDIO RX COMMUNICATION SIGNAL
1. Turn ignition switch ON.
2. Check signal between display control unit harness connector "M43" terminal 42 (R/Y) and ground with CONSULT-II or oscilloscope.
  42 (R/Y) - Ground: Refer to " TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT ".
OK or NG

Fig 5: Checking Signal Between Display Control Unit Harness Connector
Courtesy of NISSAN MOTOR CO., U.S.A.
1. OK: GO TO 7.
2. NG: Replace audio unit.
CHECK SELF-DIAGNOSIS OF DCU
1. Turn ignition switch OFF.
2. Replace display control unit.
3. Turn ignition switch ON.
4. Start self-diagnosis of DCU, and check the self-diagnosis result.
OK or NG
1. OK: INSPECTION END.
2. NG: Replace audio unit.