Suzuki Ignis Service Manual page 1664

General Description
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 sys-
tem.
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 soft-
ware 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 fol-
lows 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 table "A, 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 oper-
ational.
NOTE:
For the connector number and the terminal number discribed in diagnostic flow, refer to "Wiring Dia-
gram Manual" discribed in "Foreword" of this manual.
ENGINE GENERAL INFORMATION AND DIAGNOSIS (Z13DT ENGINE) 6-3-5
Engine Diagnosis