Reading Off The Position Of The Open-Circuit
- Ignition on.
Reading off the result from a ring break diagnostic
Click the VCT2000 symbol to read off the result of the ring break diagnostic.
The following result can be obtained from a ring break diagnostic:
If the fault occurs when the ring break diagnostic is run, the result will be presented as an open-circuit position.
If the fault does not occur when the ring break diagnostic is run, the result will be OK. If this is the case, select alternative 3 below.
- If the diagnostic indicates an open-circuit in the communication on the MOST network, the result will be an open-circuit position
- The result will be OK if there is no fault on the MOST network
- If the infotainment control module (ICM) receives a signal on the MOST network but is unable to decode it because the luminance is weak or the signals are distorted, the result will be POOR.
Determining the position of the open-circuit
The position of the open-circuit is calculated by working backwards in the MOST network from the infotainment control module (ICM).
NOTE:The ring break diagnostic always counts backwards, irrespective of which, or how many control modules, are installed in the car. To determine the position of the open-circuit, check the list to see which control modules are installed in that particular car. Then count backwards following the determined order. The number of control modules can vary between 4-9.
Two examples are outlined below:
- The first open-circuit position corresponds to 0. This means that the open-circuit is in the media player module (MPM) or in the cable between the media player module (MPM) and the infotainment control module (ICM)
- If the position is 1, go one step backwards in the chain. The open-circuit is in the phone module (PHM) or in the cable between the phone module (PHM) and the media player module (MPM). The open-circuit may be caused by the optical connector in the media player module (MPM) being damaged. This means that the media player module (MPM) is not able to interpret the incoming signal from the phone module (PHM) correctly.NOTE:
The phone module (PHM) is not standard. If one is not installed, the open-circuit position is in the subwoofer module (SUB). If only the 4 nodes in the standard set up of the MOST network are installed, open-circuit position 1 applies to the audio module (AUD).
Select the alternative for the control module to be checked.
Alternative 1:
Media player module (MPM).
Phone module (PHM).
Subwoofer module (SUB).
Global positioning system module (GPS).
See: CHECKING CABLE AND COMPONENT
Alternative 2:
Audio module (AUD).
Traffic message channel module (TMC).
AM/FM tuner module (AFM).
Multimedia module (MMM).
Infotainment control module (ICM).
See: CHECKING CABLE AND COMPONENT
Alternative 3:
The result from the ring break diagnostic indicates that the MOST network is OK.
The result from the ring break diagnostic is POOR.
See: CHECKING CABLE AND COMPONENT
Other information
- For information about location and order of control modules in the MOST network, See: LOCATION OF COMPONENTS