Subaru Legacy (2005 year). Service manual — part 914

AB(diag)-93

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

AD: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 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 rear harness, disconnect the side airbag module connector, curtain
airbag module connector and seat belt pretensioner connector for safety reasons.
WIRING DIAGRAM:

AB-01204

1

2

AB17

AB21

AB21

1 2

AIRBAG CONTROL MODULE

PRETENSIONER LH

WITH CURTAIN AIRBAG
OR LAP SEAT BELT
PRETENSIONER

1

2

*

1

: 6

*

2

: 5

WITHOUT CURTAIN AIRBAG

*

1

: 2

*

2

: 1

*

*

AB17

AB17

7 8 9 10 11 12

13 14 15 16 17 18 19

5 6

20

1 2

3 4

1 2 3 4 5 6

7 8 9 10 11 12

(WITHOUT CURTAIN AIRBAG)

(WITH CURTAIN AIRBAG

OR LAP SEAT BELT

PRETENSIONER)

AB(diag)-94

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

1. MODEL WITH CURTAIN AIRBAG OR LAP SEAT BELT PRETENSIONER

Step

Check

Yes

No

1

CHECK SEAT BELT PRETENSIONER.
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) Connect the connector (1N) in the test har-
ness N to the connector (AB21).
4) Connect the airbag resistor to connector
(2N) in the test harness N.
5) 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 seat
belt pretensioner
(LH). <Ref. to SB-
14, Front Seat
Belt.>

Go to step 2.

2

CHECK AIRBAG REAR HARNESS (PRE-
TENSIONER HARNESS LH).
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the airbag resistor from test
harness.
3) Disconnect the connector (AB19) from side
airbag module (LH).
4) Disconnect the connector (AB31) from cur-
tain airbag module (LH).
5) Disconnect the connectors (AB17) and
(AB18) from airbag 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. 11 (+) — Chassis ground (

−

):

(3U) 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
rear harness with
body harness.

AB(diag)-95

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

2. MODEL WITHOUT CURTAIN AIRBAG

Step

Check

Yes

No

1

CHECK SEAT BELT PRETENSIONER.
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) Connect the connector (1N) in the test har-
ness N to the connector (AB21).
4) Connect the airbag resistor to connector
(2N) in the test harness N.
5) 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 seat
belt pretensioner
(LH). <Ref. to SB-
14, Front Seat
Belt.>

Go to step 2.

2

CHECK AIRBAG REAR HARNESS (PRE-
TENSIONER HARNESS LH).
1) Turn the ignition switch OFF, disconnect the
battery ground cable, and wait more than 20
seconds.
2) Disconnect the airbag resistor from test
harness.
3) Disconnect the connectors (AB17) and
(AB18) from airbag control module.
4) Connect the connector (1R) in the test har-
ness R to connector (AB17).
5) Connect the battery ground cable and turn
the ignition switch to ON.
6) Measure the voltage between connector
(3R) in the test harness R and chassis ground.

Connector & terminal

(3R) No. 13 (+) — Chassis ground (

−

):

(3R) No. 11 (+) — 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)-96

AIRBAG SYSTEM (DIAGNOSTICS)

Diagnostic Chart with Trouble Code

AE: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 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