Functions of bus system analysis

Bus system analysis is a test module that automatically executes the following steps:

Step 1: Identification of engine type 

Identifying the engine type is a prerequisite for bus system analysis, since different engines generate different fault code memory entries for the same cause of fault.

Step 2: Read fault memories of all control units 

Step 3: Check fault memory entries for undervoltage 

If the vehicle has suffered an undervoltage, the undervoltage is the most likely cause of the bus failure. Bus system analysis checks whether a fault memory entry indicating undervoltage is present in at least 2 control units. If no undervoltage can be detected, continue with step 4.

Step 4: Check how many fault memory entries were found 

If at least 1 fault memory entry is present, continue with step 5.

Step 5: Evaluation of fault memory entries and creation of a list of most probable fault causes 

Bus system analysis computes the 3 most probable fault causes.

The 3 most probable fault causes are given in a list.

The most probable fault cause is at the top of the list.

The fault causes detected are as follows: ** ** Cause of fault PT-CAN ** Cause of fault ZGM * Cause of fault ... End test module [1] is the most likely cause of the fault. Select inspection step.

The number of stars denotes priority 

The stars in front of a cause of fault indicate how probable the cause of fault is. 5 stars denote the most likely cause of fault. 1 star is allocated to a cause of fault that has very low probability.

Step 6: Selection of the test module 

The BMW diagnosis system proposes a separate test plan for each of the 3 most probable fault causes.