VOLVO
ICM-U1A1587 - Incomplete MOST Ring Reported By ICM. Bus Signal / Message Failures. Missing message
System
Infotainment Control Module (ICM)
Volvo models this fault code applies to
Applies to the following models:
9 modelsS60 (2011–), S80 (2007–), V40 (2013–), V40 Cross Country (2013–), V60 (2011–), V60 Cross Country (2015–), V70 (2008–), XC60 (2009–), XC70 (2008–)
What does this fault code mean?
The ICM has found a break in the MOST network. Each control module on the MOST network is a link in a ring, so a break can switch off the infotainment functions. The fault may be in a connector, in the cable or in a control module on the network.
Possible causes
- Dirt or damage at the connection for the MOST cable
- Open circuit in the MOST cable
- Damaged MOST transceiver in one of the control modules on the network
- A control module on the MOST network has no power supply
- A damaged control module on the MOST network
What you can do
- 1Check that the fuses for the control modules in the infotainment system are intact, since a control module without power breaks the network
- 2Check that the MOST connectors are clean and seated. Dirt or damage at the connection can break the signal
- 3Look for damage to the MOST cable, such as kinked or sharply bent sections
- 4Have a workshop with diagnostic equipment find where the break is. It lies in the control module before the one the diagnosis points to, or in the cable between them
- 5Switch the ignition on for a while after the repair and check that the code is not stored again
Symptoms you may notice5
- The audio system does not work
- Navigation does not work
- Infotainment functions do not work
- Phone functions are missing or limited
- On S80 (07-), V70 (08-) and XC70 (08-) built before late August 2008: the audio unit, the radio or the phone does not work
What the fault can affect1
- The infotainment functions can be switched off completely
General guidance for car owners. Diagnosis on the car can point to a different cause.