Faulty Communication

For faults when messages cannot be sent on the MOST network, diagnostic trouble code (DTC) ICM-U1A2400 is stored.

Causes of this fault may be that:

• a control module, except the infotainment control module (ICM), has a defective optical connector
• a control module has an internal fault which means that the optical connection stops working
• a control module on the MOST network is not powered. If there is no power supply, the optical connector stops transmitting light
• the optical cable is damaged or there is an open-circuit. This fault can occur if the bend radius of the cable is too small or if the cable is kinked or trapped
• there is dirt or oil on the optical connectors which impedes the light
• the connection to a control module has come loose
• the fiber optic terminals in the connector are cross-connected
• there is a loose connection because the fiber optical wiring is incorrectly installed or the fiber optic terminal pin has been pressed back in the connector
• a bridging connector has come loose or is damaged.

Ring break diagnostics are used to remedy diagnostic trouble code (DTC) ICM-U1A2400. If a break is discovered in the MOST network after running a ring break diagnostic, diagnostic trouble code (DTC) ICM-U1A1587 will be stored in the infotainment control module (ICM). If this is the case, which control module the open-circuit is located in can be read off from the infotainment control module (ICM).