Functions of MOST system analysis

WARNING: This page does not describe the selected car, but rather 21 other vehicles, including the 2006 BMW Z4, 2006 BMW M3, 2006 BMW M Roadster, 2006 BMW M Coupe, and 2006 BMW 550i. However, it is still accessible from the selected car via links, so may be relevant.

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:
1. E60, E61, E63, E64 up to 09/2005:
  MPM: Micro-power module
2. E60, E61, E63, E64 from 09/2005
  KGM: Body-gateway module
3. E65, E66
  PM: Power module
4. E87, E90, E91, E92, E93
  JBE: Junction box electronics
Then the fault memories are read.
The following fault code memory entries are read:
1. E60, E61, E63, E64 up to 09/2005:
  MPM: Micro-power module
  
  Have the auxiliary consumer units been switched off?
2. E60, E61, E63, E64 from 09/2005
  KGM: Body-gateway module
  
  Have the auxiliary consumer units been switched off?
3. E65, E66
  PM: Power module
  
  Is there a break in the connection from the control units to the battery?
  
  Is the battery fully discharged?
4. 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 M-ASK or RAD2

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

E65, E66
CD: Control display
E60, E61, E63, E64
CCC or M-ASK: Car communication computer or multi-audio system controller
E87, E90, E91, E92, E93
RAD2: Radio 2 (BMW "Professional" radio)

If there is a problem with the communication, the appropriate fault is displayed. The test module is ended.

If the communication is in order, continue with the 3rd step.

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.

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

Step 4: Check MOST configuration

This step checks whether the fault "MOST-Ring: desired/actual configuration do not coincide" is stored in the M-ASK (E60), CCC (E60) or CD (E65). Depending on the model series concerned, the fault is stored in the following control units:

E60, E61, E63, E64, E87 and E90, E91, E92, E93
CCC or M-ASK: Car communication computer or multi-audio system controller
E87, E90, E91, E92, E93
RAD2: Radio 2 (BMW "Professional" radio)

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 code memory entries in all MOST control units are evaluated with regard to communication faults. The causes of the faults are displayed in order of their probability. The necessary procedure is described.