Subaru Legacy (2005 year). Service manual — part 904

AB(diag)-53

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

H: DTC 24 IG1 OPEN

DTC DETECTING CONDITION:
• Airbag control module is faulty.
• Airbag main harness circuit is open.
• Fuse No. 25 (in joint box) is blown.
• Body harness circuit is open.

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.
WIRING DIAGRAM:

AB6

AB6

No.25

6

IGNITION

SWITCH

BATTERY

AIRBAG CONTROL MODULE

AB-00666

1 2 3

4 5 6

7 8 9 10 11 12 13 14 15 16 17

18 19 20 21 22 23 24 25 26 27 28

AB(diag)-54

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

Step

Check

Yes

No

1

CHECK AIRBAG CONTROL MODULE.
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the connector (AB6) from air-
bag control module.
3) Connect the connector (1U) in the test har-
ness U to connector (AB6).
4) Connect the battery ground cable and turn
the ignition switch to ON.
5) Measure the resistance between connector
(2U) in the test harness U and chassis ground.

Connector & terminal

(2U) No. 1 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Replace the airbag

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

Go to step 2.

2

CHECK FUSE No. 25 (IN JOINT BOX).
1) Confirm that the ignition switch is turned
OFF.
2) Remove the fuse No. 25 (in joint box) and
perform visual inspection.

Is the fuse No. 25 blown out?

Replace the fuse
No. 25. If the fuse
No. 25 is blown
again, repair the
bulkhead harness.
Or replace the air-
bag main harness
with body harness.

Repair the body
harness.

AB(diag)-55

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

I:

DTC 25 IG2 OPEN

DTC DETECTING CONDITION:
• Airbag control module is faulty.
• Airbag main harness circuit is open.
• Fuse No. 12 (in joint box) is blown.
• Body harness circuit is open.

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.
WIRING DIAGRAM:

AB6

AB6

No.12

5

IGNITION

SWITCH

BATTERY

AIRBAG CONTROL MODULE

AB-00665

1 2 3

4 5 6

7 8 9 10 11 12 13 14 15 16 17

18 19 20 21 22 23 24 25 26 27 28

AB(diag)-56

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

Step

Check

Yes

No

1

CHECK AIRBAG CONTROL MODULE.
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the connector (AB6) from air-
bag control module.
3) Connect the connector (1U) in the test har-
ness U to connector (AB6).
4) Connect the battery ground cable and turn
the ignition switch to ON.
5) Measure the resistance between connector
(2U) in the test harness U and chassis ground.

Connector & terminal

(2U) No. 6 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Replace the airbag

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

Go to step 2.

2

CHECK FUSE No. 12 (IN JOINT BOX).
1) Confirm that the ignition switch is turned
OFF.
2) Remove the fuse No. 12 (in joint box) and
perform visual inspection.

Is the fuse No. 12 blown out?

Replace the fuse
No. 12. If the fuse
No. 12 is blown
again, repair the
bulkhead harness.
Or replace the air-
bag main harness
with body harness.

Repair the body
harness.