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

WARNING: This page is about a different car, the 2008 Nissan Maxima. 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

OK: GO TO 2.

NG: Check the malfunctioning parts.

CHECK HARNESS

Turn ignition switch OFF.
Disconnect display control unit (A) connector M95 and audio unit (B) connector M45.

Check continuity between audio unit and display control unit.

AUDIO UNIT AND DISPLAY CONTROL UNIT

Terminals				Continuity
A		B
Connector	Terminal	Connector	Terminal
M95	40	M45	23	Yes
M95	42	M45	21	Yes

Check continuity between display control unit and ground.

DISPLAY CONTROL UNIT AND GROUND

Terminals			Continuity
Display control unit (+)		(-)
Connector	Terminal	(-)
M95	40	Ground	No
M95	42	Ground	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.

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 40 and ground.
  Approx. 3.5V or more
Fig 2: Checking Voltage Between Display Control Unit Harness Connector M95 Terminal 40 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK: GO TO 4.

NG: Replace display control unit. Refer to "DISPLAY CONTROL UNIT ".
CHECK 2: AUDIO-RX COMMUNICATION SIGNAL
1. Connect audio unit connector.
2. Turn ignition switch ON.
3. Check voltage between display control unit harness connector M95 terminal 42 and ground.
  Approx. 3.5V or more
Fig 3: Checking Signal Between Display Control Unit Connector M95 Terminal 42 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK: GO TO 5.

NG: Replace audio unit. Refer to "AUDIO UNIT ".
CHECK 3: AUDIO-TX COMMUNICATION SIGNAL
1. Turn ignition switch ON.
2. Check signal between display control unit harness connector M95 terminal 40 and ground with CONSULT-III or oscilloscope.
  40 - Ground: Refer to "TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT ".
Fig 4: Checking Signal Between Display Control Unit Connector M95 Terminal 40 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK: GO TO 6.

NG: Replace audio unit. Refer to "AUDIO UNIT ".
CHECK 4: AUDIO-RX COMMUNICATION SIGNAL
1. Turn ignition switch ON.
2. Check signal between display control unit harness connector M95 terminal 42 and ground with CONSULT-III or oscilloscope.
  42 - Ground: Refer to "TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT ".
Fig 5: Checking Signal Between Display Control Unit Harness Connector M95 Terminal 42 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK: Replace audio unit. Refer to "AUDIO UNIT ".

NG: Replace display control unit. Refer to "DISPLAY CONTROL UNIT ".