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Home >> Volvo >> 2007 >> V50 T-5, AWD, Standard >> Repair and Diagnosis >> Accessories & Equipment >> Entertainment Systems >> BLUETOOTH Phone Module (Bpm), Infotainment Control Module (ICM), Media Player Module (MPM), Multimedia Module (Mmm), Phone Module (PHM) And Remote Digital Audio Receiver (RDAR) Module Diagnostic Trouble Codes >> ICM-Dc01: Communication Module. Faulty Signal (2007) >> Faulty Signal >> Checks >> Checking The Wiring And Component
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Checking The Wiring And Component

The infotainment module (IAM) has detected a communication break in the MOST network.

The MOST network is a fiber optic ring network in which all control modules connected to it must be supplied with current and grounded to ensure proper functioning of the infotainment system. Should a control module for any reason be unable to process (receive or transmit) the MOST signals or if there is a break in the fiber optic cable, the infotainment module (ICM) will shut down all functionality.

Communication on the fiber optic network is one-way. The MOST network control module receives the light signals, amplifies them and then retransmits them. The MOST connectors for the control modules contain two fiber optic cables, one for incoming and one for outgoing signals.

If the fault is intermittent it will have been registered on an earlier occasion but is no longer present. Intermittent faults may either be due to interference on starting the MOST network or to an intermittent power supply and/or grounding fault in a control module forming part of the network. The fault will be assessed from case to case. If the fault recurs, carry out fault tracing as for a permanent fault.

An intermittent fault may be difficult to diagnose using ring break diagnosis because a condition for this is that the fault occurs while the diagnostics program is running.

If the fault is permanent it will be necessary to run a ring break diagnosis to locate the break.

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