DTC Logic

WARNING: This page is about a different car, the 2011 Nissan 370Z. However, it is still accessible from the selected car via links, so may be relevant.

DTC DETECTION LOGIC

DTC	Display contents of CONSULT-III	DTC detection condition	Possible malfunction factor
U121B	HDD COMM [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.