Subaru Legacy (2005 year). Service manual — part 908

AB(diag)-69

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

2. MODEL WITHOUT CURTAIN AIRBAG

Step

Check

Yes

No

1

CHECK SIDE AIRBAG MODULE.
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the connector (AB25) from
(AB24), and connect the connector (1F) in test
harness F to connector (AB24).
3) Connect the airbag resistor to connector
(3F) in the test harness F.
4) Connect the battery ground cable and turn
the ignition switch to ON.

Does the airbag warning light
illuminate for 6 seconds and go
off?

Replace the side
airbag module
(RH). <Ref. to AB-
18, REMOVAL,
Side Airbag Mod-
ule.>

Go to step 2.

2

CHECK AIRBAG REAR HARNESS (SIDE
AIRBAG MODULE 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 airbag resistor from test
harness.
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) Connect the battery ground cable and turn
the ignition switch to ON.
8) Measure the voltage between connector
(3R) in the test harness R and chassis ground.

Connector & terminal

(3R) No. 20 (+) — Chassis ground (

−

):

(3R) No. 18 (+) — Chassis ground (

−

):

Is the voltage less than 1 V?

Replace the airbag
control module.
<Ref. to AB-22,
Airbag Control
Module.>

Replace the airbag
rear harness with
body harness.

AB(diag)-70

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

Q: DTC 46 SIDE AIRBAG LH FAILURE

DTC DETECTING CONDITION:
• Side airbag harness (LH) circuit is shorted to power supply.
• 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

AB(diag)-71

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

1. MODEL WITH CURTAIN AIRBAG OR LAP SEAT BELT PRETENSIONER

Step

Check

Yes

No

1

CHECK SIDE AIRBAG MODULE.
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the connector (AB20) from
(AB19), and connect the connector (1F) in test
harness F to connector (AB19).
3) Connect the airbag resistor to connector
(3F) in the test harness F.
4) Connect the battery ground cable and turn
the ignition switch to ON.

Does the airbag warning light
illuminate for 6 seconds and go
off?

Replace the side
airbag module
(LH). <Ref. to AB-
18, REMOVAL,
Side Airbag Mod-
ule.>

Go to step 2.

2

CHECK AIRBAG REAR HARNESS (SIDE
AIRBAG MODULE HARNESS LH).
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the connector (AB21) from seat
belt pretensioner (LH).
3) Disconnect the connector (AB31) from cur-
tain airbag module (LH).
4) Disconnect the airbag resistor from test
harness.
5) Disconnect the connector (AB17) from air-
bag control module.
6) Connect the connector (1U) in the test har-
ness U to connector (AB17).
7) Connect the battery ground cable and turn
the ignition switch to ON.
8) Measure the resistance between connector
(3U) in the test harness U and chassis ground.

Connector & terminal

(3U) No. 12 (+) — Chassis ground (

−

):

(3U) No. 10 (+) — Chassis ground (

−

):

Is the voltage less than 1 V?

Replace the airbag
control module.
<Ref. to AB-22,
Airbag Control
Module.>

Replace the airbag
rear harness with
body harness.

AB(diag)-72

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

2. MODEL WITHOUT CURTAIN AIRBAG

Step

Check

Yes

No

1

CHECK SIDE AIRBAG MODULE.
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the connector (AB20) from
(AB19), and connect the connector (1F) in test
harness F to connector (AB19).
3) Connect the airbag resistor to connector
(3F) in the test harness F.
4) Connect the battery ground cable and turn
the ignition switch to ON.

Does the airbag warning light
illuminate for 6 seconds and go
off?

Replace the side
airbag module
(LH). <Ref. to AB-
18, REMOVAL,
Side Airbag Mod-
ule.>

Go to step 2.

2

CHECK AIRBAG REAR HARNESS (SIDE
AIRBAG MODULE HARNESS LH).
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the connector (AB21) from seat
belt pretensioner (LH).
3) Disconnect the connector (AB31) from cur-
tain airbag module (LH).
4) Disconnect the airbag resistor from test
harness.
5) Disconnect the connector (AB17) from air-
bag control module.
6) Connect the connector (1R) in the test har-
ness R to connector (AB17).
7) Connect the battery ground cable and turn
the ignition switch to ON.
8) Measure the voltage between connector
(3R) in the test harness R and chassis ground.

Connector & terminal

(3R) No. 12 (+) — Chassis ground (

−

):

(3R) No. 10 (+) — Chassis ground (

−

):

Is the voltage less than 1 V?

Replace the airbag
control module.
<Ref. to AB-22,
Airbag Control
Module.>

Replace the airbag
rear harness with
body harness.