1999 SUBARU LEGACY ESP

IEach connector number shown in the wiring dia-
gram corresponds to that in the wiring harness.
The location of each connector in the actual
vehicle is determined by reading the first character
of the connector (for example, a ªFº for F8, ªiº for
i16, etc.) and the type of wiring harness.
The first character of each connector number
refers to the area or system of the vehicle.
Symbol Wiring harness and Cord
F Front wiring harness
B Bulkhead wiring harness
E Engine wiring harness
T Transmission cord
DDoor cord LH & RH, Rear
gate cord
IInstrument panel wiring har-
ness
RRear wiring harness, Rear
defogger cord
Room light cord,
Fuel tank cord,
Sunroof cord,
Trunk lid cord
P Floor wiring harness
G6M0205
2. Basic Diagnostics
Procedures
A: BASIC PROCEDURE
1. GENERAL
The most important purpose of diagnostics is to
determine which part is malfunctioning quickly, to
save time and labor.
2. IDENTIFICATION OF TROUBLE
SYMPTOM
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 problems are encountered, check the
component parts.
5. CONFIRMATION OF SYSTEM
OPERATION
After repairing, ensure that the system operates
properly.
B: 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 compo-
nent terminal.
2) Contact the positive probe of the voltmeter on
connector (A).
The voltmeter will indicate a voltage.
6
6-3[D2A1]WIRING DIAGRAM
2. Basic Diagnostics Procedures

3) Shift the positive probe to connector (B). The
voltmeter will indicate no voltage.
G6M0206
4) With test set-up held as it is, turn switch ON.
The voltmeter will indicate a voltage and, at the
same time, the light will come on.
5) The circuit is in good order. If a problem such
as a lamp failing to light 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.
G6M0207
3) Symbol ªq-qº indicates that continuity exists
between two points or terminals. For example,
when a switch position is ª3º, continuity exists
among terminals 1, 3 and 6, as shown in table.
B6M0749
3. HOW TO DETERMINE AN OPEN
CIRCUIT
1) Voltmeter method:
An open circuit is determined by measuring the
voltage between respective connectors and
ground using a voltmeter, starting with the connec-
tor closest to the power supply. The power supply
must be turned ON so that current flows in the cir-
cuit. If voltage is not present between a particular
connector and ground, the circuit between that
connector and the previous connector is open.
G6M0208
2) Ohmmeter method:
Disconnect all connectors affected, and check con-
tinuity in the wiring between adjacent connectors.
When the ohmmeter indicates ªinfiniteº, the wiring
is open.
G6M0209
7
[D2B3]6-3WIRING DIAGRAM
2. Basic Diagnostics Procedures

4. HOW TO DETERMINE A
SHORT-CIRCUIT
1) Test lamp method:
Connect a test lamp (rated at approximately 3
watts) in place of the blown fuse and allow current
to flow through the circuit. Disconnect one connec-
tor at a time from the circuit, starting with the one
located farthest from the power supply. If the test
lamp goes out when a connector is disconnected,
the wiring between that connection and the next
connector (farther from the power supply) is
shorted.
G6M0210
2) Ohmmeter method:
Disconnect all affected connectors, and check con-
tinuity between each connector and ground. When
ohmmeter indicates continuity between a particular
connector and ground, that connector is shorted.
G6M0211
3. Working Precautions
A: PRECAUTIONS WHEN WORKING
WITH THE PARTS MOUNTED ON
THE VEHICLE
1) When working under a vehicle which is jacked-
up, always be sure to use safety stands.
2) The parking brake must always be applied dur-
ing working. Also, in automatic transmission
vehicles, keep the select lever set to the P (Park-
ing) range.
3) Be sure the workshop is properly ventilated
when running the engine. Further, be careful not to
touch the belt or fan while the engine is operating.
4) Be careful not to touch hot metal parts, espe-
cially the radiator and exhaust system immediately
after the engine has been shut off.
B: PRECAUTIONS IN TROUBLE
DIAGNOSIS AND REPAIR OF
ELECTRIC PARTS
1) The battery cable must be disconnected from
the battery's (þ) terminal, and the ignition switch
must be set to the OFF position, unless otherwise
required by the diagnostics.
2) Securely fasten the wiring harness with clamps
and slips so that the harness does not interfere
with the body end parts or edges and bolts or
screws.
3) When installing parts, be careful not to catch
them on the wiring harness.
4) When disconnecting a connector, do not pull
the wires, but pull while holding the connector
body.
G6M0212
8
6-3[D2B4]WIRING DIAGRAM
3. Working Precautions

4. HOW TO DETERMINE A
SHORT-CIRCUIT
1) Test lamp method:
Connect a test lamp (rated at approximately 3
watts) in place of the blown fuse and allow current
to flow through the circuit. Disconnect one connec-
tor at a time from the circuit, starting with the one
located farthest from the power supply. If the test
lamp goes out when a connector is disconnected,
the wiring between that connection and the next
connector (farther from the power supply) is
shorted.
G6M0210
2) Ohmmeter method:
Disconnect all affected connectors, and check con-
tinuity between each connector and ground. When
ohmmeter indicates continuity between a particular
connector and ground, that connector is shorted.
G6M0211
3. Working Precautions
A: PRECAUTIONS WHEN WORKING
WITH THE PARTS MOUNTED ON
THE VEHICLE
1) When working under a vehicle which is jacked-
up, always be sure to use safety stands.
2) The parking brake must always be applied dur-
ing working. Also, in automatic transmission
vehicles, keep the select lever set to the P (Park-
ing) range.
3) Be sure the workshop is properly ventilated
when running the engine. Further, be careful not to
touch the belt or fan while the engine is operating.
4) Be careful not to touch hot metal parts, espe-
cially the radiator and exhaust system immediately
after the engine has been shut off.
B: PRECAUTIONS IN TROUBLE
DIAGNOSIS AND REPAIR OF
ELECTRIC PARTS
1) The battery cable must be disconnected from
the battery's (þ) terminal, and the ignition switch
must be set to the OFF position, unless otherwise
required by the diagnostics.
2) Securely fasten the wiring harness with clamps
and slips so that the harness does not interfere
with the body end parts or edges and bolts or
screws.
3) When installing parts, be careful not to catch
them on the wiring harness.
4) When disconnecting a connector, do not pull
the wires, but pull while holding the connector
body.
G6M0212
8
6-3[D2B4]WIRING DIAGRAM
3. Working Precautions

4. How to Use Wiring Diagram
B6M0213B
A: RELAY
A symbol used to indicate a relay.
B: CONNECTOR-1
The sketch of the connector indicates the one-pole
types.
C: WIRING CONNECTION
Some wiring diagrams are indicated in foldouts for
convenience. Wiring destinations are indicated
where necessary by corresponding symbols (as
when two pages are needed for clear indication).
D: FUSE No. & RATING
The ªFUSE No. & RATINGº corresponds that used
in the fuse box (main fuse box, and joint box).
E: CONNECTOR-2
IEach connector is indicated by a symbol.
IEach terminal number is indicated in the corre-
sponding wiring diagram in an abbreviated form.
IFor example, terminal number ªC2º refers to No.
2 terminal of connector (C: F41) shown in the con-
nector sketch.
10
6-3[D400]WIRING DIAGRAM
4. How to Use Wiring Diagram

F: CONNECTOR SKETCH
IEach connector sketch clearly identifies the
shape and color of a connector as well as terminal
locations. Non-colored connectors are indicated in
natural color.
IWhen more than two types of connector number
are indicated in a connector sketch, it means that
the same type connectors are used.
G: GROUND
Each grounding point can be located easily by
referring to the corresponding wiring harness.
H: DIODE
A symbol is used to indicate a diode.
I: WIRE TRACING ON EXTENDED
WIRING DIAGRAMS
For a wiring diagram extending over at least two
pages, a symbol (consisting of the same charac-
ters with arrows), as shown below, facilitates wire
tracing from one page to the next.
A¨A, B¨B
J: SYMBOLS OF WIRE
CONNECTION AND CROSSING
B6M0750A
K: POWER SUPPLY ROUTING
A symbol is used to indicate the power supply in
each wiring diagram.
ªMB-5º, ªMB-6º, etc., which are used as power sup-
ply symbols throughout the text, correspond with
those shown in the POWER SUPPLY ROUTING in
the wiring diagram.
Accordingly, using the POWER SUPPLY ROUT-
ING and wiring diagrams permits service person-
nel to understand the entire electrical arrangement
of a system.
L: S.M.J.
A symbol is used to indicate the terminal arrange-
ment of the super multiple junction. The S.M.J. is
not shown in respective wiring diagrams but is indi-
cated on the next page.
M: SYMBOLS AND
ABBREVIATIONS
A number of symbols and abbreviations are used
in each wiring diagram to easily identify parts or
circuits.
N: ABBREVIATION LIST
Abbr. Full name
ABS Antilock Brake System
ACC Accessory
A/C Air Conditioning
AD Auto Down
AT Automatic Transmission
AU Auto Up
+B Battery
DN Down
DRL Daytime Running Light
E Ground
F/B Fuse & Joint Box
FL1.5 Fusible link 1.5 mm
2
IG Ignition
Illumi. Illumination
LH Left Hand
Lo Low
M Motor
M/B Main Fuse Box
MG Magnet
Mi Middle
OP Optional Parts
PASS Passing
RH Right Hand
SBF Slow Blow Fuse
S.M.J. Super Multiple Junction
ST Starter
SW Switch
TCS Traction Control System
UP Up
WASH Washer
11
[D4N0]6-3WIRING DIAGRAM
4. How to Use Wiring Diagram