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 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 

  See: VERIFICATION 

Select the control module to check according to the list.

1. Traffic message channel module (TMC).

   See: CHECKING CABLE AND COMPONENT TMC 

2. Phone module (PHM)

   See: CHECKING CABLE AND COMPONENT PHM 

3. Subwoofer Module (SUB)

   See: CHECKING CABLE AND COMPONENT SUB 

4. Global positioning system module (GPS).

   See: CHECKING CABLE AND COMPONENT GPS 

5. Integrated audio module (IAM).

   See: CHECKING FUSES 

Select the control module to check according to the list.

1. Audio Control Module (AUD).

   See: CHECKING CABLE AND COMPONENT AUD 

2. Multimedia module (MMM).

   See: CHECKING CABLE AND COMPONENT 

3. Infotainment Control Module (ICM).

   See: CHECKING CABLE AND COMPONENT 

• Ignition off
• Unplug the MOST cable connector from the infotainment module (TCM).
• Ignition on
• Activate the infotainment system.

  Visually check that the infotainment control module (TCM) emits light from the MOST connector.

  If no light is emitted by the infotainment control module (ICM) then the control module is damaged.

  If the infotainment module (ICM) does emit light, the fault lies in the MOST cable to the next control module.

  Inspect the MOST connection for dirt, loose contacts and damage.

  If no fault can be found in the MOST connection, change the MOST cable.

  Remedy as necessary.

  Other information 

  • See: INFORMATION AND ENTERTAINMENT DISPLAY
  • See: FIBER OPTIC CABLE HARNESS, REPAIRING
  • See: COMPONENT LOCATIONS (2005, 2006)

• Continue 

  See: VERIFICATION 

Checking fuses 

Check that the fuse for the function in question is intact.

Replace the fuse if it is damaged.

Checking the cause of the fault 

Check the cause of the fault as follows:

1. Ignition off
2. Unplug the MOST connector from the multimedia module (MMM).
3. Connect the MOST cable to special tool 9512867 .
4. Ignition on
5. Activate the infotainment system.
6. 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.
7. If the parameter shows that the MOST network is not closed, check the receiving control module in the same way as described above.

If menu text is displayed, communication on the MOST network is OK. The cause of the fault then lies in the multimedia module (MMM). Continue fault tracing by checking the component.

If menu text is not displayed, communication on the MOST network is not OK. The cause of the fault then lies in the next control module. Continue fault tracing by checking the fiberoptic cable.

Checking the cable 

• Inspect the MOST connection for dirt, loose contacts and damage.
• If no fault can be found in the MOST connection, change the MOST cable.

Checking the component 

• Check the multimedia module (MMM) power supply and ground connection.
• Inspect the MOST connection for dirt, loose contacts and damage.
• If no fault can be found, change the multimedia module (MMM).

Remedy as necessary.

Other information 

• See: CONTROL MODULE INFORMATION AND ENTERTAINMENT
• See: CHECKING THE SUPPLY VOLTAGE/GROUND TERMINAL
• See: SIGNAL SPECIFICATION (2004-2007)
• See: FIBER OPTIC CABLE HARNESS, REPAIRING
• See: DIAGNOSTIC INSTRUCTIONS - FIBER OPTIC CABLE
• See: COMPONENT LOCATIONS (2005, 2006)

• Continue 

  See: VERIFICATION