2. Check Mute Signal

WARNING: This page is about a different car, the 2004 Infiniti Q45. However, it is still accessible from the selected car via links, so may be relevant.

Connect voice activated control module connector and audio unit connector.
Turn ignition switch ON.
Check the following.

Fig 1: Checking Mute Signal
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK: Replace audio unit.
NG: Replace voice activated control module.