Subaru Legacy (2005 year). Manual — part 909

AB(diag)-73

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

R: DTC 51 SIDE AIRBAG SENSOR RH FAILURE

DTC DETECTING CONDITION:
• Side airbag sensor (RH) is faulty.
• Side airbag harness (RH) circuit is faulty.
• Airbag control module is faulty.

CAUTION:
• Before diagnosing the airbag system, be sure to turn the ignition switch OFF, disconnect the
ground cable from battery, and wait more than 20 seconds before starting to work.
• When replacing the airbag module, seat belt pretensioner, roll connector, control module and sen-
sor, reconnect each part and check that the warning light operates properly.
• When inspecting the airbag main harness, disconnect the airbag module connector of the driver’s
and passenger’s seats for safety reasons.
• When inspecting the airbag rear harness, disconnect the side airbag module connector, curtain
airbag module connector, seat belt pretensioner connector and lap seat belt pretensioner connector
for safety reasons.
WIRING DIAGRAM:

AB-01201

AB18

AB24

AB25

1

2

AB28

3

4

1

2

7

8

15

17

13

16

AB18

AB28

AB24

1 2

AIRBAG CONTROL MODULE

SIDE AIRBAG

MODULE RH

SIDE AIRBAG

SENSOR RH

7 8 9 10 11 12

13 14 15 16 17 18 19

5 6

20

1 2

3 4

1 2 3 4

1

2

10

12

7

9

:

:

WC

OC

WITH CURTAIN AIRBAG
OR LAP SEAT BELT
PRETENSIONER

WITHOUT CURTAIN AIRBAG

WC

OC

AB18

2 3 4 5 6

8 9 10 11 12

(WITHOUT CURTAIN AIRBAG)

(WITH CURTAIN AIRBAG

OR LAP SEAT BELT

PRETENSIONER)

1

7

AB(diag)-74

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

1. MODEL WITH CURTAIN AIRBAG OR LAP SEAT BELT PRETENSIONER

Step

Check

Yes

No

1

CHECK AIRBAG REAR HARNESS (SIDE
AIRBAG SENSOR HARNESS RH).
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the connector (AB26) from seat
belt pretensioner (RH).
3) For the model with lap seat belt preten-
sioner, disconnect the connector (AB30) from
lap seat belt pretensioner.
4) Disconnect the connector (AB33) from cur-
tain airbag module (RH).
5) Disconnect the connector (AB25) from
(AB24).
6) Disconnect the connector (AB18) from air-
bag control module.
7) Connect the connector (1U) in the test har-
ness U to connector (AB18).
8) Disconnect the connector (AB28) from side
airbag sensor (RH), and connect the connector
(2V) in test harness V to connector (AB28).
9) Measure the resistance between connector
(4U) in the test harness U and connector (3V)
in the test harness V.

Connector & terminal

(4U) No. 5 — (3V) No. 2:
(4U) No. 7 — (3V) No. 1:
(4U) No. 8 — (3V) No. 5:
(4U) No. 6 — (3V) No. 4:

Is the resistance less than 10
Ω?

Go to step 2.

Replace the airbag
rear harness with
body harness.

2

CHECK AIRBAG REAR HARNESS (SIDE
AIRBAG SENSOR HARNESS RH).
Measure the resistance between connector
(4U) in the test harness U and chassis ground.

Connector & terminal

(4U) No. 5 — Chassis ground:
(4U) No. 7 — Chassis ground:
(4U) No. 8 — Chassis ground:
(4U) No. 6 — Chassis ground:

Is the resistance more than 1
M

Ω?

Replace the side
airbag sensor
(RH). <Ref. to AB-
23, Side Airbag
Sensor.> When
the sensor is not
OK though the
sensor is replaced,
replace the airbag
control module.
<Ref. to AB-22,
Airbag Control
Module.>

Replace the airbag
rear harness with
body harness.

AB(diag)-75

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

2. MODEL WITHOUT CURTAIN AIRBAG

Step

Check

Yes

No

1

CHECK AIRBAG REAR HARNESS (SIDE
AIRBAG SENSOR HARNESS RH).
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the connector (AB26) from seat
belt pretensioner (RH).
3) Disconnect the connector (AB33) from cur-
tain airbag module (RH).
4) Disconnect the connector (AB25) from
(AB24).
5) Disconnect the connector (AB18) from air-
bag control module.
6) Connect the connector (1R) in the test har-
ness R to connector (AB18).
7) Disconnect the connector (AB28) from side
airbag sensor (RH), and connect the connector
(2V) in test harness V to connector (AB28).
8) Measure the resistance between connector
(4R) in the test harness R and connector (3V)
in the test harness V.

Connector & terminal

(4R) No. 5 — (3V) No. 2:
(4R) No. 7 — (3V) No. 1:
(4R) No. 8 — (3V) No. 5:
(4R) No. 6 — (3V) No. 4:

Is the resistance less than 10
Ω?

Go to step 2.

Replace the airbag
rear harness with
body harness.

2

CHECK AIRBAG REAR HARNESS (SIDE
AIRBAG SENSOR HARNESS RH).
Measure the resistance between connector
(4R) in the test harness R and chassis ground.

Connector & terminal

(4R) No. 5 — Chassis ground:
(4R) No. 7 — Chassis ground:
(4R) No. 8 — Chassis ground:
(4R) No. 6 — Chassis ground:

Is the resistance more than 1
M

Ω?

Replace the side
airbag sensor
(RH). <Ref. to AB-
23, Side Airbag
Sensor.> When
the sensor is not
OK though the
sensor is replaced,
replace the airbag
control module.
<Ref. to AB-22,
Airbag Control
Module.>

Replace the airbag
rear harness with
body harness.

AB(diag)-76

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

S: DTC 52 SIDE AIRBAG SENSOR LH FAILURE

DTC DETECTING CONDITION:
• Side airbag sensor (LH) is faulty.
• Side airbag harness (LH) circuit is faulty.
• Airbag control module is faulty.

CAUTION:
• Before diagnosing the airbag system, be sure to turn the ignition switch OFF, disconnect the
ground cable from battery, and wait more than 20 seconds before starting to work.
• When replacing the airbag module, seat belt pretensioner, roll connector, control module and sen-
sor, reconnect each part and check that the warning light operates properly.
• When inspecting the airbag main harness, disconnect the airbag module connector of the driver’s
and passenger’s seats for safety reasons.
• When inspecting the airbag rear harness, disconnect the side airbag module connector, curtain
airbag module connector and seat belt pretensioner connector for safety reasons.
WIRING DIAGRAM:

AB-01202

AB23

1

2

AB19

AB20

3

4

1

2

10

9

17

20

16

18

AB19

1 2

AB17

AB17 AIRBAG CONTROL MODULE

SIDE AIRBAG

MODULE LH

SIDE AIRBAG

SENSOR LH

7 8 9 10 11 12

13 14 15 16 17 18 19

5 6

20

1 2

3 4

AB23

1 2 3 4

:

:

WC

OC

WITH CURTAIN AIRBAG
OR LAP SEAT BELT
PRETENSIONER

WITHOUT CURTAIN AIRBAG

(WITH CURTAIN AIRBAG

OR LAP SEAT BELT

PRETENSIONER)

AB17

(WITHOUT CURTAIN AIRBAG)

1 2 3 4 5 6

7 8 9 10 11 12

6

5

10

12

7

9

WC

OC