Subaru Legacy IV (2008 year). Manual - part 1023

 

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Subaru Legacy IV (2008 year). Manual - part 1023

 

 

AB(diag)-80

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK POOR CONTACT IN CONNECTORS.
Check for poor contact of the connectors 
between the airbag control module and the seat 
belt pretensioner LH.

Is there poor contact?

Replace the airbag 
rear harness along 
with body harness.

Go to step 2.

2

CHECK SEAT BELT PRETENSIONER.
1) Turn the ignition switch to OFF, disconnect 
the battery ground cable, and wait for 20 sec-
onds or more.
2) Disconnect the connector (AB21) from seat 
belt pretensioner (LH).
3) Connect the connector (1N) in the test har-
ness N to the connector (AB21).
4) Connect the airbag resistor to the connector 
(2N) of test harness N.
5) Connect the battery ground terminal and 
turn the ignition switch to ON.

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

Replace the seat 
belt pretensioner 
(LH). <Ref. to SB-
18, Front Seat 
Belt.>

Go to step 3.

3

CHECK AIRBAG REAR HARNESS (PRE-
TENSIONER HARNESS LH).
1) Turn the ignition switch to OFF, disconnect 
the battery ground cable, and wait for 20 sec-
onds or more.
2) Disconnect the airbag resistor from test har-
ness.
3) Disconnect connector (AB19) from side air-
bag module (LH).
4) Disconnect the connector (AB31) from cur-
tain airbag module (LH).
5) Disconnect the connectors (AB6, AB17, 
AB18) from airbag control module.
6) Connect the test harness AG connector 
(1AG) to the connectors (AB6, AB17, AB18).
7) Connect the battery ground terminal and 
turn the ignition switch to ON.
8) Measure the voltage between connector 
(3AG) in the test harness AG and chassis 
ground.

Connector & terminal

(3AG) No. 10 (+) — Chassis ground (–):
(3AG) No. 12 (+) — Chassis ground (–):

Is the voltage less than 1 V?

Go to step 4.

Replace the airbag 
rear harness along 
with body harness.

4

CHECK AIRBAG CONTROL MODULE.
1) Connect all connectors.
2) Clear the memory.
3) Perform the Inspection Mode.
4) Read the DTC. 

Is the same DTC displayed?

Replace the airbag 
control module. 
<Ref. to AB-20, 
Airbag Control 
Module.>

Go to step 5.

5

CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed?

Check DTC using 
“List of Diagnostic 
Trouble Code 
(DTC)”. <Ref. to 
AB(diag)-38, List 
of Diagnostic Trou-
ble Code (DTC).>

Finish the diagno-
sis.

AB(diag)-81

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

AD:DTC 71 DRIVER’S AIRBAG FAILURE

DTC DETECTING CONDITION:
• Airbag main harness circuit is open, shorted or shorted to ground.
• Airbag module harness (Driver’s side) circuit is open, shorted or shorted to ground.
• Roll connector circuit is open, shorted or shorted to ground.
• Driver’s airbag module is faulty.
• Airbag control module is faulty.

CAUTION:
• Before diagnosing the airbag system, be sure to turn the ignition switch to OFF, disconnect the
ground cable from the battery, and wait 20 seconds or more 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 connectors of the driver’s
and passenger’s seats for safety.
• When inspecting the airbag rear harness, disconnect the side airbag module connector, curtain
airbag module connector and seat belt pretensioner connector for safety reasons.

NOTE:
Prior to starting work, prepare two airbag resistors (98299PA040).
WIRING DIAGRAM:

AIRBAG CONTROL MODULE

7

8

5

6

AB6

AB2

AB2

AB7

AB6

AB38

2

1

2

1

2

1

AB38

AB37

1 2 3 4

2

1

AB37

18 19 20

21 22 23 24 25 26 27 28

1 2 3

5 6 7 8

10

9

4

11 12 13 14

16 17

15

29 30

AB-01761

4

3

2

1

STEERING
ROLL CONNECTOR

DRIVER'S

AIRBAG MODULE

AB(diag)-82

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK POOR CONTACT IN CONNECTORS.
Check for poor contact of the connectors 
between the airbag control module and the 
driver’s airbag module.

Is there poor contact?

Replace the airbag 
main harness 
along with body 
harness.

Go to step 2.

2

CHECK DRIVER’S AIRBAG MODULE.
1) Turn the ignition switch to OFF, disconnect 
the battery ground cable, and wait for 20 sec-
onds or more.
2) Remove the driver’s airbag module.
3) Connect the connector (1N) in the test har-
ness N to the connector (AB38).
4) Connect the airbag resistor to the connector 
(2N) of test harness N.
5) Connect the connector (1Q) in the test har-
ness Q to connector (AB37).
6) Connect the airbag resistor to the connector 
(2Q) in the test harness Q.
7) Connect the battery ground terminal 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-14, Driver’s Air-
bag Module.>

Go to step 3.

3

CHECK ROLL CONNECTOR.
1) Turn the ignition switch to OFF, disconnect 
the battery ground cable, and wait for 20 sec-
onds or more.
2) Disconnect the test harness N from connec-
tor (AB38).
3) Disconnect the test harness Q from connec-
tor (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 the connec-
tors (2P) and (3P) of test harness P.
7) Connect the battery ground terminal 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 4.

4

CHECK AIRBAG MAIN HARNESS (DRIV-
ER’S AIRBAG HARNESS).
1) Turn the ignition switch to OFF, disconnect 
the battery ground cable, and wait for 20 sec-
onds or more.
2) Disconnect the airbag resistor from the con-
nectors (2P) and (3P) of test harness P.
3) Remove the instrument panel side cover on 
the passenger’s side and disconnect the con-
nectors (AB10) and (AB9).
4) Disconnect the connectors (AB6, AB17, 
AB18) from the airbag control module, and con-
nect the test harness AG connector (1AG).
5) Measure the resistance between connector 
(3AG) in the test harness AG and connectors 
(2P) and (3P) in the test harness P.

Connector & terminal

(3AG) No. 2 — (3P) No. 3:
(3AG) No. 4 — (3P) No. 4:

Is the resistance less than 10 

:? Go to step 5.

Replace the airbag 
main harness 
along with body 
harness.

AB(diag)-83

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

5

CHECK AIRBAG MAIN HARNESS (DRIV-
ER’S AIRBAG HARNESS).
Measure the resistance between connectors 
(3AG) in the test harness AG, and between con-
nector (3AG) and chassis ground.

Connector & terminal

(3AG) No. 1 — (3AG) No. 2:
(3AG) No. 1 — (3AG) No. 4:
(3AG) No. 2 — (3AG) No. 3:
(3AG) No. 3 — (3AG) No. 4:
(3AG) No. 1 — (3AG) No. 3:
(3AG) No. 3 — Chassis ground:
(3AG) No. 1 — Chassis ground:
(3AG) No. 2 — (3AG) No. 4:
(3AG) No. 2 — Chassis ground:
(3AG) No. 4 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 6.

Replace the airbag 
main harness 
along with body 
harness.

6

CHECK AIRBAG CONTROL MODULE.
1) Connect all connectors.
2) Clear the memory.
3) Perform the Inspection Mode.
4) Read the DTC. 

Is the same DTC displayed?

Replace the airbag 
control module. 
<Ref. to AB-20, 
Airbag Control 
Module.>

Go to step 7.

7

CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed?

Check DTC using 
“List of Diagnostic 
Trouble Code 
(DTC)”. <Ref. to 
AB(diag)-38, List 
of Diagnostic Trou-
ble Code (DTC).>

Finish the diagno-
sis.

Step

Check

Yes

No

 

 

 

 

 

 

 

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