Subaru Legacy IV (2008 year). Service manual — part 1022

AB(diag)-76

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

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) Measure the resistance between connector
(3AG) in the test harness AG and connector
(2N) in the test harness N.

Connector & terminal

(3AG) No. 12 — (2N) No. 1:
(3AG) No. 10 — (2N) No. 2:

Is the resistance less than 10

:? Go to step 4.

Replace the airbag
rear harness along
with body harness.

4

CHECK AIRBAG REAR HARNESS (PRE-
TENSIONER HARNESS LH).
Measure the resistance between connector
(3AG) terminals in the test harness AG.

Connector & terminal

(3AG) No. 10 — (3AG) No. 12:

Is the resistance 1 M

: or

more?

Go to step 5.

Replace the airbag
rear harness along
with body harness.

5

CHECK AIRBAG REAR HARNESS (PRE-
TENSIONER HARNESS LH).
Measure the resistance 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 resistance 1 M

: or

more?

Go to step 6.

Replace the airbag
rear 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

AB(diag)-77

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

AB:DTC 65 BELT PRETENSIONER RH FAILURE

DTC DETECTING CONDITION:
• Seat belt pretensioner (RH) circuit is shorted to power supply.
• Pretensioner is faulty.
• Pretensioner harness 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.
WIRING DIAGRAM:

2

1

AB18

AB26

4

3

AB26

1 2

AB18

AB-02108

18 19 20 21 22 23 24

1 2 3 4

11 12 13 14

16

17

15

AIRBAG CONTROL MODULE

PRETENSIONER RH

10

8

7

6

5

9

AB(diag)-78

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 RH.

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 (AB26) from seat
belt pretensioner (RH).
3) Connect the connector (1N) in the test har-
ness N to the connector (AB26).
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
(RH). <Ref. to SB-
18, Front Seat
Belt.>

Go to step 3.

3

CHECK AIRBAG REAR HARNESS (PRE-
TENSIONER HARNESS RH).
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 (AB24) from side air-
bag module (RH).
4) Disconnect the connector (AB33) from cur-
tain airbag module (RH).
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. 20 (+) — Chassis ground (–):
(3AG) No. 18 (+) — 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)-79

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

AC:DTC 66 BELT PRETENSIONER LH FAILURE

DTC DETECTING CONDITION:
• Seat belt pretensioner (LH) circuit is shorted to power supply.
• Pretensioner is faulty.
• Pretensioner harness 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.
WIRING DIAGRAM:

AB-02109

AB21

1 2

2

1

AB17

AB21

5

6

AB17

18 19 20 21 22 23 24

1 2 3 4

11 12 13 14

16

17

15

10

8

7

6

5

9

AIRBAG CONTROL MODULE

PRETENSIONER LH