Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 794

WI-5

Basic Diagnostic Procedure

WIRING SYSTEM

C: HOW TO READ WIRING DIAGRAMS

1. WIRING DIAGRAM:

The wiring diagram of each system is illustrated so that you can understand the path through which the elec-

tric current flows from the battery.

Sketches and codes are used in the diagrams. They should read as follows:

• Each connector and its terminal position are indicated by a sketch of the connector in a disconnected state

which is viewed from the front.

• The number of poles or pins, presence of a lock are indicated in the sketch of each connector. In the

sketch, the highest pole number refers to the number of poles which the connector has. For example, the

sketch of the connector shown in figure indicates the connector has 9 poles.

WI-02746

Viewed from this direction

4

2

4

1

3

Connector used in vehicle

Sketch

Symbol

Number of poles

Numbered in order from upper
right to lower left.

Numbered in order from upper
left to lower right.

Connector shown in wiring diagram

Double frames

Indicates a lock 
is included.

Indicates the number of poles.

4

3

2

1

9

8

7

6

5

Indicates a lock is included.

Single frame

1

2

3

4

5

6

7

8

9

WI-02747

WI-6

Basic Diagnostic Procedure

WIRING SYSTEM

• When one set of connectors is viewed from the

front side, the pole numbers of one connector are

symmetrical to those of the other. When these two

connectors  are  connected  as  a  unit,  the  poles

which have the same number are joined.

• WIRING DIAGRAM:

The connectors are numbered along with the num-

ber of poles, external colors, and mating connec-

tions in the accompanying list.

• The sketch of each connector in the wiring dia-

gram usually shows the (A) side of the connector.

The  relationship  between  the  wire  color,  terminal

number and connector is described in the figure.
NOTE:

A wire which runs in one direction from a connector

terminal sometimes may have a different color from

that which runs in the other direction from that ter-

minal.

• In the wiring diagram, connectors which have no

terminal number refer to one-pole types. Sketches

of these connectors are omitted intentionally.

• The  following  color  codes  are  used  to  indicate

the colors of the wires.

1

1

2

2

3

3

4

4

5

5

6

6

WI-00107

WI-02748

Wire color :

BR (No. 1 terminal)
RW (No. 3 terminal)

i2

3 4

1 2

BR

RW

i2

F4

1
3

(A)

B

B

B15

F10

WI-00109

Color code

Color

L

Blue

B

Black

Y

Yellow

G

Green

R

Red

W

White

Br

Brown

Lg

Light green

Gr

Gray

P

Pink

Or

Orange

Sb

Light blue

V

Violet

SA

Sealed (Inner)

SB

Sealed (Outer)

WI-00110

YL

2

YG

1

SB

10

YL

9

YG

8

SA

1

SB

22

SA

20

YG

YL

SB

SB

SA

WI-7

Basic Diagnostic Procedure

WIRING SYSTEM

• The wire color code, which consists of two letters

(or  three  letters  including  Br  or  Lg),  indicates  the

standard color (base color of the wire covering) by

its first letter and the stripe marking by its second

letter.

• The table lists the nominal sectional areas and

allowable currents of the wires.
CAUTION:

When replacing or repairing a wire, be sure to

use the same size and type of the wire which

was originally used.
NOTE:

• The allowable current in the table indicates the

tolerable amperage of each wire at an ambient

temperature of 40°C (104°F).

• The  allowable  current  changes  with  ambient

temperature. Also, it changes if a bundle of more

than two wires is used.

• Each unit is either directly grounded to the body

or indirectly grounds through a harness ground ter-

minal. Different symbols are used in the wiring dia-

gram to identify the two grounding systems.

• The ground points shown in the wiring diagram

refer to the following:
NOTE:

All  wiring  harnesses  are  provided  with  a  ground

point which must be securely connected.

Nominal sec-

tional area

No. of 

strands/

strand diam-

eter

Outside 

diameter of 

wiring

Allowable 

current

Amps/

40°C (104°F)

mm

2

mm

0.3

7/0.26

1.8

7

0.5

7/0.32

2.2 (or 2.0)

12

0.75

30/0.18

2.6 (or 2.4)

16

0.85

11/0.32

2.4 (or 2.2)

16

1.25

16/0.32

2.7 (or 2.5)

21

2

26/0.32

3.1 (or 2.9)

28

3

41/0.32

3.8 (or 3.6)

38

5

65/0.32

4.6 (or 4.4)

51

8

50/0.45

5.5

67

Y B

Black

Marking color :
Reference color :

Yellow

WI-03797

Direct ground

Indirect terminal
ground

B

WI-02750

WI-18706

: AIRBAG  
  GROUND

GAB

: BODY  
  GROUND

GB

: ENGINE  
  GROUND

GE

: AIR PUMP  
  GROUND

GP

: VDC  
  GROUND

GV

WI-8

Basic Diagnostic Procedure

WIRING SYSTEM

• Relays are classified as normally-open or normally-closed.

The normally-closed relay has one or more contacts. The wiring diagram shows the relay mode when the en-

ergizing circuit is OFF.

WI-16724

Relay type

4-pole

6-pole

4-pole

6-pole

Normally-open type

Normally-closed type

Mixed type

Key to symbols:

: Current flows.

: Current does not flow.

Energizing circuit OFF

Energizing circuit ON