Subaru Legacy (2005 year). Manual - part 916

AB(diag)-101

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

AG:DTC 75 DRIVER’S AIRBAG FAILURE

DTC DETECTING CONDITION:
• Airbag main harness (Driver’s side) circuit is shorted to power supply.
• Airbag module harness (Driver’s side) circuit is shorted to power supply.
• Roll connector is shorted to power supply.
• Driver’s airbag module 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.
WIRING DIAGRAM:

16

17

13

14

AB6

AB2

AB2

AB7

1

2

3

4

AB6

AB38

1

2

1

2

2

1

AB38

AIRBAG CONTROL MODULE

STEERING
ROLL CONNECTOR

AIRBAG MODULE

(DRIVER SIDE)

AB37

1 2 3 4

2

1

AB37

AB-01256

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)-102

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

Step

Check

Yes

No

1

CHECK DRIVER’S AIRBAG MODULE.
1) Turn the ignition switch OFF, disconnect the 
battery ground cable, and wait more than 20 
seconds.
2) Remove the driver’s airbag module.
3) Connect the connector (AB38) to the con-
nector (1N) in the test harness N.
4) Connect the airbag resistor to connector 
(2N) in the test harness N.
5) Connect the connector (1Q) in the test har-
ness Q to connector (AB37).
6) Connect the airbag resistor to connector 
(2Q) in the test harness Q.
7) 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 
driver’s airbag 
module. <Ref. to 
AB-16, Driver’s 
Airbag Module.>

Go to step 2.

2

CHECK ROLL CONNECTOR.
1) Turn the ignition switch OFF, disconnect the 
battery ground cable, and wait more than 20 
seconds.
2) Disconnect the test harness N from con-
nector (AB38).
3) Disconnect the test harness Q from con-
nector (AB37).
4) Remove the instrument panel lower cover 
and disconnect the connector (AB7) from 
(AB2).
5) Connect the connector (1P) in the test har-
ness P to connector (AB2).
6) Connect the airbag resistor to connectors 
(2P) and (3P) in the test harness P.
7) 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 roll 
connector. <Ref. to 
AB-25, Roll Con-
nector.>

Go to step 3.

3

CHECK AIRBAG MAIN HARNESS (DRIV-
ER’S AIRBAG HARNESS).
1) Turn the ignition switch OFF, disconnect the 
battery ground cable, and wait more than 20 
seconds.
2) Disconnect the airbag resistor from con-
nectors (2P) and (3P) in the test harness P.
3) Remove the instrument panel side cover on 
passenger’s side and disconnect the connec-
tors (AB10) and (AB9).
4) Disconnect the connector (AB6) from air-
bag control module, and connect the connector 
(1U) in the test harness U. 
5) Connect the battery ground cable and turn 
the ignition switch to ON. (engine OFF)
6) Measure the resistance between connector 
(2U) in the test harness U and chassis ground.

Connector & terminal

(2U) No. 4 (+) — Chassis ground (

−

):

(2U) No. 2 (+) — Chassis ground (

−

):

(2U) No. 8 (+) — Chassis ground (

−

):

(2U) No. 12 (+) — Chassis ground (

−

):

Is the voltage less than 1 V?

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

Replace the airbag 
main harness with 
body harness.

AB(diag)-103

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

AH:DTC 76 PASSENGER’S AIRBAG FAILURE

DTC DETECTING CONDITION:
• Airbag main harness (Passenger’s side) circuit is shorted to power supply.
• Airbag module harness (Passenger’s side) circuit is shorted to power supply.
• Passenger’s airbag module 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.
WIRING DIAGRAM:

AB-01257

AB6

  AIRBAG MODULE  
(PASSENGER SIDE)

AB9

AB9

AB10

11

10

3

4

7

8

1

2

AIRBAG CONTROL MODULE

AB6

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

1 2 3 4

AB(diag)-104

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

Step

Check

Yes

No

1

CHECK PASSENGER’S AIRBAG MODULE.
1) Turn the ignition switch OFF, disconnect the 
battery ground cable, and wait more than 20 
seconds.
2) Remove the instrument panel side cover on 
the passenger’s side.
3) Disconnect the connector (AB10) from 
(AB9).
4) Connect the connector (1P) in the test har-
ness P to connector (AB9).
5) Connect the airbag resistor to connectors 
(2P) and (3P) in the test harness P.
6) 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 pas-
senger’s airbag 
module. <Ref. to 
AB-17, Passen-
ger’s Airbag Mod-
ule.>

Go to step 2.

2

CHECK AIRBAG MAIN HARNESS (PASSEN-
GER’S AIRBAG HARNESS).
1) Turn the ignition switch OFF, disconnect the 
battery ground cable, and wait more than 20 
seconds.
2) Disconnect the airbag resistor from con-
nectors (2P) and (3P) in the test harness P.
3) Remove the instrument panel lower cover 
and disconnect the connector (AB7) from 
(AB2).
4) Disconnect the connector (AB6) from air-
bag control module, and connect the connector 
(1U) in the test harness U. 
5) Measure the resistance between connector 
(2U) in the test harness U and chassis ground.

Connector & terminal

(2U) No. 3 (+) — Chassis ground (

−

):

(2U) No. 5 (+) — Chassis ground (

−

):

(2U) No. 9 (+) — Chassis ground (

−

):

(2U) No. 13 (+) — Chassis ground (

−

):

Is the voltage less than 1 V?

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

Replace the airbag 
main harness with 
body harness.