DTC Logic

WARNING: This page is about a different car, the 2012 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.

DTC	Display contents of CONSULT	DTC detection condition	Possible malfunction factor
U121B	HDDCOMM [U121B]	AV control unit malfunction is detected.	If the music box function has no malfunctions, then there is a possibility of the detection of a temporary malfunction. Replace the AV control unit if the malfunction occurs constantly. Refer to "REMOVAL AND INSTALLATION ".