Functions of MOST System Analysis

The "MOST system analysis" test module follows the following sequence:

Step 1: Read fault code memories of MPM, KGM, PM or JBE 

• It first checks whether the communication with the following control units is in order:
  • > R56

    JBE: Junction box electronics

  • > E60, E61, E63, E64 up to 09/2005

    MPM: micro-power module

  • > E60, E61, E63, E64 from 09/2005

    KGM: body gateway module

  • > E65, E66

    PM: power module

  • > E70

    JBE: Junction box electronics

  • > E81, E87, E90, E91, E92, E93

    JBE: Junction box electronics

• Then the fault memories are read.

  The following fault code memory entries are read:

  • > R56

    JBE: Junction box electronics

    Have the auxiliary consumer units been switched off?

  • > E60, E61, E63, E64 up to 09/2005

    MPM: micro-power module

    Have the auxiliary consumer units been switched off?

  • > E60, E61, E63, E64 from 09/2005

    KGM: body gateway module

    Have the auxiliary consumer units been switched off?

  • > E65, E66

    PM: power module

    Is there a break in the connection from the control units to the battery?

    Is the battery fully discharged?

  • > E70

    JBE: Junction box electronics

    Have the auxiliary consumer units been switched off?

  • > E81, E87, E90, E91, E92, E93

    JBE: Junction box electronics

    Have the auxiliary consumer units been switched off?

Step 2: Check communication with CD or CCC or CHAMP or M - ASK or RAD2 

A check is performed as to whether the communication with the following control units is OK:

• > R56

  CCC or RAD2: Car Communication Computer or radio 2 (Radio Boost)

• > E65, E66

  CD: Control display

• > E60, E61, E63, E64

  CCC or M-ASK or CHAMP: Car Communication Computer or multi-audio system controller or Central Head unit And Multimedia Platform

• > E70

  CCC or M-ASK or CHAMP: Car Communication Computer or multi-audio system controller or Central Head unit And Multimedia Platform

• > E81, E87, E90, E91, E92, E93

  RAD2: radio 2 (BMW radio "Professional")

If there is a problem with the communication, the appropriate fault is displayed.

The test module is ended.

If communications with the headset are OK, continue with step 3.

(Headset: In the field of automobiles, the headset is the user interface for systems that are not essential for driving, for example navigation, mobile telephone or radio. Headset is a collective term for various control units, for example CCC, CHAMP, M-ASK, e.g in MOST system analysis).

Step 3: Check MOST ring 

Is the MOST ring closed?

If the MOST ring has been interrupted a fault message is displayed. The test module is ended and reference given to the ring interruption diagnosis.

If the MOST ring is closed, continue with step 4.

Step 4: Check MOST configuration 

This step checks whether the fault "MOST - Ring: desired/actual configuration do not coincide" is stored. Depending on the model series concerned, the fault is stored in the following control units:

• > R56

  CCC: Car Communication Computer

  RAD2: radio 2 (Radio Boost)

• > E60, E61, E63, E64

  CCC or M-ASK or CHAMP: Car Communication Computer or multi-audio system controller or Central Head unit And Multimedia Platform

• > E70

  CCC or M-ASK or CHAMP: Car Communication Computer or multi-audio system controller or Central Head unit And Multimedia Platform

• > E81, E87, E90, E91, E92, E93

  CCC or M-ASK: car communication computer or multi - audio system controller

  RAD2: radio 2 (BMW radio "Professional")

The test compares the desired configuration of the MOST bus with the actual configuration.

If the actual configuration differs from the desired configuration then the desired configuration for the control units is stored again in the MOST network.

If the desired configuration is stored, continue with the 5th step.

Step 5: Analyze fault memory of the MOST control units 

The fault memory entries in all MOST control units are evaluated with regard to communication faults. The evaluation of the fault memory entries present will give the most probable cause of the fault.

At most the 2 most probable causes of the fault (control units) will be given as a result, e.g.:

• CDC CD changer (****)
• TEL Telephone (**)

Evaluation of quality of results:

(*****) stands for high quality (most probable fault)

(*) stands for poor quality

The number of stars varies between one star and five stars.