Diagnostic Trouble Code (DTC) Information ICM-U1A1587

Condition

The infotainment control module (ICM) can detect an open-circuit in the MOST network after the ring break diagnostic has been run.

The diagnostic trouble code is stored if the control module detects that:

The network is not connected.

The control module's test for the diagnostic trouble code (DTC) starts in the event of:

Ignition switch position I and II.

NOTE:

The control module can only detect the fault once the test has been started and the diagnostic trouble code (DTC) is stored when the conditions are met.

Fig 1: Identifying Infotainment Control Module (ICM)

Courtesy of VOLVO CARS CORPORATION

Substitute Value

None.

Possible Source

Dirty or damaged terminal for the MOST cable.
Open-circuit in the MOST cable.
MOST transceiver is damaged in one of the control modules in the MOST network.
No power supply to a control module in the MOST network.
Damaged control module in the MOST network.

Fault symptom[s]

Audio system does not function
Navigation; No Functionality
Infotainment functions do not work
Missing or reduced functionality in the phone