Satellite Radio Tuner (Factory Installed) Communication Circuit Inspection

WARNING: This page is about a different car, the 2007 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.

CHECK HARNESS - 1
1. Turn ignition switch OFF.
2. Disconnect satellite radio tuner (factory installed) connector M128 and audio unit connector M127.
3. Check continuity between satellite radio tuner (factory installed) harness connector M128 (A) terminal 28 and audio unit harness connector M127 (B) terminal 48
  Continuity should exist.
4. Check continuity between satellite radio tuner (factory installed) harness connector M128 (A) terminal 28 and ground.
  Continuity should not exist.
  
  Fig 1: Checking Continuity Between Satellite Radio Tuner (Factory Installed) Connector M128 Terminal 28 And Ground
OK or NG

OK: GO TO 2.

NG: Repair harness or connector.
CHECK HARNESS - 2
1. Check continuity between satellite radio tuner (factory installed) harness connector M128 (A) terminal 29 and audio unit harness connector M127 (B) terminal 49
  Continuity should exist.
2. Check continuity between satellite radio tuner (factory installed) harness connector M128 (A) terminal 29 and ground.
  Continuity should not exist.
OK or NG

OK: GO TO 3.

NG: Repair harness or connector.

Fig 2: Checking Continuity Between Satellite Radio Tuner (Factory Installed) Connector M128 Terminal 29 And Ground
CHECK HARNESS - 3
1. Check continuity between satellite radio tuner (factory installed) harness connector M128 (A) terminal 30 and audio unit harness connector M127 (B) terminal 50
  Continuity should exist.
2. Check continuity between satellite radio tuner (factory installed) harness connector M128 (A) terminal 30 and ground.
  Continuity should not exist.
  
  Fig 3: Checking Continuity Between Satellite Radio Tuner (Factory Installed) Connector M128 Terminal 30 And Ground
OK or NG

OK: GO TO 4.

NG: Repair harness or connector.
CHECK REQ1 SIGNAL
1. Connect satellite radio tuner (factory installed) connector and audio unit connector.
2. Turn ignition switch to ACC
3. Check signal between satellite radio tuner (factory installed) harness connector M128 terminal 28 and ground with CONSULT-II or oscilloscope.
  28 - Ground : Refer to "TERMINALS AND REFERENCE VALUE FOR SATELLITE RADIO TUNER ".
  
  Fig 4: Checking Signal Between Satellite Radio Tuner Harness Connector B30 Terminal 28 And Ground
OK or NG

OK: GO TO 5.

NG: Replace audio unit. Refer to "AUDIO UNIT ".
CHECK TXD SIGNAL
1. Check signal between satellite radio tuner (factory installed) harness connector M128 terminal 29 and ground with CONSULT-II or oscilloscope.
  29 - Ground : Refer to "TERMINALS AND REFERENCE VALUE FOR SATELLITE RADIO TUNER ".
  
  Fig 5: Checking Signal Between Satellite Radio Tuner Connector M128 Terminal 29 And Ground
OK or NG

OK: GO TO 6.

NG: Replace audio unit. Refer to "AUDIO UNIT ".
CHECK RXD SIGNAL
1. Check signal between satellite radio tuner (factory installed) harness connector M128 terminal 30 and ground with CONSULT-II or oscilloscope.
  30 - Ground : Refer to "TERMINALS AND REFERENCE VALUE FOR SATELLITE RADIO TUNER ".
OK or NG

OK: Replace satellite radio tuner (factory installed). Refer to "SATELLITE RADIO TUNER ".

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

Fig 6: Checking Signal Between Satellite Radio Tuner Connector M128 Terminal 30 And Ground