Technical information

Checking Procedure
General Information
This Checking Procedure contains the diagnosis of the following
electronic system:

Immobiliser
Vehicle Diagnostic Concept:
The main purpose of a vehicle diagnostic concept is locating and eliminating
faults in the shortest time possible. Therefore, the following diagnostic strategy
has been developed as a guideline that leads technicians straight to the source
fault:
Starting point is the vehicle that contains a certain number of electronic systems,
e.g. engine management system, airbag, and ABS system.
Each of these electronic systems consists of so - called "functional groups" that
are functionally related to each other. A Coolant Temperature Sensor Circuit for
example represents such a functional group.
Each of the functional groups consists of several components, such as switches,
sensors, wires etc. A Coolant Temperature Sensor Circuit for example is made
up of a sensor, a wiring harness, a control unit, and the software of the control
unit.
Based on this structure, the first diagnostic step should be the identification and
localisation of the defective electronic system, next comes the diagnosis of the
corresponding defective functional group, and finally, locate and repair of the
defective component within that group.
The Diagnostic System Check (described in table A, Diagnostic System Check)
of this checking procedure follows that diagnostic path. Diagnosis of an
electronic system according to the above described concept always starts with
this Main Check.
The instructions described in the Diagnostic System Check section must be
followed closely. Every time a test or test step is passed without fault, the
Diagnostic System Check continues with the next step. Some of the tests
include references to related functional groups (tables B-x). When there is a
fault, the corresponding functional group tests are performed in order to detect
the defective functional group. When that group has been identified, the
troubleshooting tables (C-
x) are used to locate the faulty component. After repair
of the fault, the affected functional group (tables B-x) must be rechecked to
continue after this test at the appropriate position of the Diagnostic System
Check (table A).
When all test steps of the Diagnostic System Check have been completed
successfully, the system is fully operational.
Safety Measures
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