Subaru Impreza WRX 2010 Impreza Incl WRX And STi Wiring Diagram PDF

WI-3
Basic Diagnostic Procedure
WIRING SYSTEM
1. Basic Diagnostic Procedure
A: BASIC PROCEDURES
1. GENERAL DESCRIPTION
The most important purpose of diagnostics is to
quickly determine which part is malfunctioning, to
save time and labor.
2. IDENTIFICATION OF TROUBLE SYMP-
TOM
Determine what the problem is based on the symp-
tom.
3. PROBABLE CAUSE OF TROUBLE
Look at the wiring diagram and check the system’s
circuit. Then check the switch, relay, fuse, ground,
etc.
4. LOCATION AND REPAIR OF TROUBLE
1) Using the diagnostics, narrow down the causes.
2) If necessary, use a voltmeter, ohmmeter, etc.
3) Before replacing certain component parts
(switch, relay, etc.), check the power supply,
ground, for open wiring harness, poor connectors,
etc. If no problem is encountered, check the com-
ponent parts.
5. SYSTEM OPERATION CHECK
After repairing, ensure that the system operates
properly.
B: BASIC INSPECTION
1. VOLTAGE MEASUREMENT
1) Using a voltmeter, connect the negative lead to a
good ground point or negative battery terminal and
the positive lead to the connector or component ter-
minal.
2) Contact the positive lead of the voltmeter on
connector (A). The voltmeter will indicate a voltage.
3) Touch connector (B) with the positive probe. The
voltmeter will indicate no voltage.
4) With the test set-up held as it is, turn the switch
to ON. The voltmeter will indicate a voltage and, at
the same time, the light will illuminate.
5) The circuit is in good order. If a problem such as
a light failing to illuminate occurs, use the proce-
dures outlined above to track down the malfunc-
tion.
2. CIRCUIT CONTINUITY CHECKS
1) Disconnect the battery terminal or connector so
there is no voltage between the check points.
Contact the two leads of an ohmmeter to each of
the check points.
If the circuit has diodes, reverse the two leads and
check again.
2) Use an ohmmeter to check for diode continuity.
When contacting the negative lead to the diode
positive side and the positive lead to the negative
side, there should be continuity.
When contacting the two leads in reverse, there
should be no continuity.
3) The symbol indicates that continuity
exists between two points or terminals. For exam-
ple, when a switch position is at “3”, continuity ex-
ists among terminals 1, 3 and 6, as shown in the
table below.
To power
Fuse
supply
Switch
Light
V
(A)
(B)
WI-02739
Continuity No continuity
WI-02740
Ter m i na l
Switch Position
OFF
1
2
3
4
1
234
56
WI-02741
asieps.book 3 ページ 2012年8月16日 木曜日 午前9時6分

Summary of Content

WI-3Basic Diagnostic ProcedureWIRING SYSTEM1. Basic Diagnostic ProcedureA: BASIC PROCEDURES1. GENERAL DESCRIPTIONThe most important purpose of diagnostics is toquickly determine which part is malfunctioning, tosave time and labor.2. IDENTIFICATION OF TROUBLE SYMP-TOMDetermine what the problem is based on the symp-tom.3. PROBABLE CAUSE OF TROUBLELook at the wiring diagram and check the systemscircuit. Then check the switch, relay, fuse, ground,etc.4. LOCATION AND REPAIR OF TROUBLE1) Using the diagnostics, narrow down the causes.2) If necessary, use a voltmeter, ohmmeter, etc.3) Before replacing certain component parts(switch, relay, etc.), check the power supply,ground, for open wiring harness, poor connectors,etc. If no problem is encountered, check the com-ponent parts.5. SYSTEM OPERATION CHECKAfter repairing, ensure that the system operatesproperly.B: BASIC INSPECTION1. VOLTAGE MEASUREMENT1) Using a voltmeter, connect the negative lead to agood ground point or negative battery terminal andthe positive lead to the connector or component ter-minal.2) Contact the positive lead of the voltmeter onconnector (A). The voltmeter will indicate a voltage.3) Touch connector (B) with the positive probe. Thevoltmeter will indicate no voltage.4) With the test set-up held as it is, turn the switchto ON. The voltmeter will indicate a voltage and, atthe same time, the light will illuminate.5) The circuit is in good order. If a problem such asa light failing to illuminate occurs, use the proce-dures outlined above to track down the malfunc-tion.2. CIRCUIT CONTINUITY CHECKS1) Disconnect the battery terminal or connector sothere is no voltage between the check points.Contact the two leads of an ohmmeter to each ofthe check points.If the circuit has diodes, reverse the two leads andcheck again.2) Use an ohmmeter to check for diode continuity.When contacting the negative lead to the diodepositive side and the positive lead to the negativeside, there should be continuity.When contacting the two leads in reverse, thereshould be no continuity.3) The symbol indicates that continuityexists between two points or terminals. For exam-ple, when a switch position is at 3, continuity ex-ists among terminals 1, 3 and 6, as shown in thetable below.To powerFusesupplySwitchLightV(A)(B)WI-02739Continuity No continuityWI-02740Ter m i na lSwitch PositionOFF1234123456WI-02741asieps.book 3