DTC B1591: No Response from Audio HU; DTC B15D1: Audio HU Disconnected: Description

The display and navigation module display and radio receiver assembly are connected by the MOST communication line.

When an MOST communication error occurs between the display and navigation module display and the radio receiver assembly, these DTCs will be stored.

DTC No.	DTC Detection Condition	Trouble Area
B1591	No response to the diagnostic memory request from the master unit.	Radio receiver assembly power source circuit MOST circuit between display and navigation module display and radio receiver assembly MOST circuit between radio receiver assembly and stereo component amplifier assembly Radio receiver assembly Display and navigation module display
B15D1*1	A device that is listed in the MOST network connected device record of the master unit is missing.

HINT:

*1: Even if no fault is present, this DTC may be stored depending on the battery condition or engine start voltage.
The display and navigation module display is the master unit.