VOLVO
IHU-U1A1587 - Incomplete MOST Ring Reported By IHU. Bus Signal / Message Failures. Missing message
System
Infotainment Head Unit (IHU)
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 infotainment head unit (IHU) can detect a break in the MOST network through a ring break check. The code is stored when such a ring break is found, which can cause several systems connected to the MOST network to stop working.
Possible causes
- Dirt or damage at the MOST wire connection
- A break in the MOST wire
- A damaged MOST transceiver in one of the control modules on the MOST network
- A control module on the MOST network has no power supply
- A damaged control module on the MOST network
What you can do
- 1Clear the code and check whether it returns
- 2Check that the fuses are intact
- 3Check that the MOST wire connections are clean and firmly seated, and free from dirt and damage
- 4Check that the MOST wire has no break or damage along its entire length
- 5If the fault remains, have a workshop trace the MOST network further, including control modules that may lack a power supply
Symptoms you may notice4
- The mobile phone does not work
- The audio unit does not fully work
- The radio does not work
- Navigation does not work
General guidance for car owners. Diagnosis on the car can point to a different cause.