Checking Cable And Component
If the result of the ring break diagnosis is POOR it indicates that the infotainment module (ICM) receives signals on the MOST network but cannot decode them because the light strength is too weak or the signals are distorted.
If the result of the ring break diagnosis is OK it indicates that the fault is intermittent.
Fault tracing with ring break diagnosis presupposes that the fault is permanent or active while the test is running, i. e. when the system is powered up after a period without power.
HINT: If diagnostic trouble code ICM-DC01 is generated intermittently, obtain a ring break diagnosis status reading in Vehicle Communication frozen values.
Bypass the control modules on the MOST network one at a time to check network communication. Proceed as follows:
- Ignition off
- Unplug the MOST connector from the relevant control module.
- Connect the MOST cable to special tool see 9512867 .
- Ignition on
- Activate the infotainment system.
- Check that MOST network communication is in working order. Do this by obtaining a status reading of the MOST locked parameter for at least 30 seconds. This parameter shows whether the MOST network is closed and communication possible. Click on the VCT2000 symbol to obtain a MOST network status reading.
If MOST network communication is stable when a control module is disconnected, check the power supply and ground connection of the control module for an intermittent fault. If no fault is found, try changing individual components.
- Continue
Refer to VERIFICATION