Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 632

AB(diag)-67

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

K: DTC 26 PASSENGER’S AIRBAG INDICATOR FAILURE

DTC DETECTING CONDITION:

• Passenger’s airbag indicator is faulty.

• Airbag control module is faulty.

• Airbag main harness circuit is open or shorted.

• Body harness circuit is open.
CAUTION:

• Before diagnosing the airbag system, be sure to turn the ignition switch to OFF, disconnect the

ground cable from battery, and wait 60 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:

Airbag system <Ref. to WI-82, WIRING DIAGRAM, Airbag System.>

Step

Check

Yes

No

1

CHECK FOR POOR CONTACT.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait for 60 sec-
onds or more.
2) Check that the connector between the air-
bag control module and the clock is securely
connected.

Is there poor contact of any
connector?

Repair the bulk-
head harness. Or
replace the airbag
main harness
along with body
harness.

Go to step

2.

2

CHECK AIRBAG MAIN HARNESS.
1) Disconnect the connectors (AB6, AB17,
AB18) from airbag control module.
2) Connect the battery ground terminal and
turn the ignition switch to ON.
NOTE:

Neither of ON/OFF illuminates when it is nor-
mal.

Does the passenger’s airbag
indicator illuminate?

Go to step

3.

Go to step

4.

AB6

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

B31

1

2

3 4 5 6

i59

1 2 3 4 5
6 7 8 9 10

i3

1 2

3 4

5 6 7 8 9 10

16

11

15

14

13

12

17

19

18

23

25

24

20

22

21

26

28

27

AB6

3

4

i3

i59

8

4

6

17

23

16

17

B38

B31

AB1

AB-02612

CLOCK

PASSENGER'S

AIRBAG ON INDICATOR

PASSENGER'S

AIRBAG OFF INDICATOR

TO POWER SUPPLY

CIRCUIT

FB-33

F/B FUSE NO. 11

(IG)

AIRBAG CM

AB(diag)-68

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

3

CHECK AIRBAG MAIN HARNESS.
1) Turn the ignition switch to OFF.
2) Remove the clock and disconnect the con-
nector (i59).
3) Disconnect the connectors (AB6, AB17,
AB18) from the airbag control module, and con-
nect the connector (1AH) in the test harness
AH.
4) Connect the connector (2AH) in the test har-
ness AH and the connector (1AG) in the test
harness AG.
5) Measure the resistance between connector
(2AG) in the test harness AG and chassis
ground.

Connector & terminal

(2AG) No. 9 — (2AG) No. 8:
(2AG) No. 9 — Chassis ground:
(2AG) No. 8 — Chassis ground:

Is the resistance 1 MΩ or
more?

Replace the clock.
<Ref. to IDI-21,
REMOVAL,
Clock.>

Repair the bulk-
head harness. Or
replace the airbag
main harness
along with body
harness.

4

CHECK AIRBAG MAIN HARNESS.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors (AB6, AB17,
AB18) from the airbag control module, and con-
nect the connector (1AH) in the test harness
AH.
3) Connect the connector (2AH) in the test har-
ness AH and the connector (1AG) in the test
harness AG.
4) Connect the connectors (7AG) and (8AG) in
the test harness AG.
5) Connect the battery ground terminal and
turn the ignition switch to ON.

Does the passenger’s airbag
indicator illuminate?

Replace the airbag
control module.
<Ref. to AB-21,
Airbag Control
Module.>

Go to step

5.

5

CHECK AIRBAG MAIN HARNESS.
1) Turn the ignition switch to OFF.
2) Remove the clock, and disconnect the con-
nector (i59).
3) Measure the resistance between connector
(2AG) in the test harness AG and connector
(i59).

Connector & terminal

(2AG) No. 9 — (i59) No. 4:
(2AG) No. 8 — (i59) No. 3:

Is the resistance less than 10

Ω?

Go to step

6.

Repair the bulk-
head harness. Or
replace the airbag
main harness
along with body
harness.

6

CHECK BODY HARNESS.
1) Turn the ignition switch to ON.
2) Measure the voltage between connector
(i59) and chassis ground.

Connector & terminal

(i59) No. 8 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Replace the clock.
<Ref. to IDI-21,
REMOVAL,
Clock.>

Check the power
supply circuit of the
clock.

Step

Check

Yes

No

AB(diag)-69

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

L: DTC 27 ODS COMMUNICATION ERROR

DTC DETECTING CONDITION:

• Communication to the occupant detection control module is faulty.

• Airbag rear harness circuit is open, shorted, shorted to ground or shorted to power supply.

• Occupant detection harness (seat harness) is faulty.

• Occupant detection system 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 battery, and wait 60 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 rear harness, disconnect the side airbag module connector, curtain

airbag module connector and seat belt pretensioner connector for safety reasons.

WIRING DIAGRAM:

Airbag system <Ref. to WI-82, WIRING DIAGRAM, Airbag System.>

Step

Check

Yes

No

1

CHECK POOR CONTACT OF CONNEC-
TORS.
Check for poor contact of the connectors
between the airbag control module and the
occupant detection control module.

Is there poor contact?

Reconnect the
connector. If defec-
tive is not
improved, replace
the airbag rear har-
ness along with the
body harness or
the occupant
detection harness
(seat harness).

Go to step

2.

1 2 3 4 5 6 7 8 9

11 12 13 14 15 16 17 18

10

AB61

AB53

1

3

4 5 6

2

1 2

3 4 5

6 7 8 9 10 11 12

R82

1

5

2

4

10

9

15

14

6 7

11 12

3

8

13

AB18

R82

R81

12

AB18

12

13

3

1

2

AB61

9

10

5

AB59

AB53

AB-02490

OCCUPANT DETECTION

CONTROL MODULE

AIRBAG CM

TO POWER

SUPPLY CIRCUIT

FB-47

F/B FUSE NO. 25

(IG)

AB(diag)-70

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

2

CHECK AIRBAG REAR HARNESS.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait for 60 sec-
onds or more.
2) Disconnect the connectors (AB59) and
(AB53) under the passenger’s seat.
3) Disconnect the connectors (AB6, AB17,
AB18) from the airbag control module, and con-
nect the connector (1AH) in the test harness
AH.
4) Connect the connector (2AH) in the test har-
ness AH and the connector (1AG) in the test
harness AG.
5) Connect the connector (1AB) in the test har-
ness AB to the connector (AB53).
6) Measure the resistance between connector
(5AG) in the test harness AG and connector
(2AB) in the test harness AB.

Connector & terminal

(5AG) No. 5 — (2AB) No. 2:
(5AG) No. 16 — (2AB) No. 1:

Is the resistance less than 10

Ω?

Go to step

3.

Replace the airbag
rear harness along
with body harness.

3

CHECK AIRBAG REAR HARNESS.
Measure the resistance between connector
(5AG) in the test harness AG and chassis
ground.

Connector & terminal

(5AG) No. 5 — Chassis ground:
(5AG) No. 16 — Chassis ground:
(5AG) No. 5 — (5AG) No. 16:

Is the resistance less than 1
MΩ?

Go to step

4.

Replace the airbag
rear harness along
with body harness.

4

CHECK OCCUPANT DETECTION HAR-
NESS.
1) Turn the ignition switch to ON.
2) Measure the voltage between connector
(2AB) in the test harness AB and chassis
ground.

Connector & terminal

(2AB) No. 3 (+) — Chassis ground (–):

Is the voltage 9 V or more?

Replace the occu-
pant detection har-
ness (seat
harness). If defec-
tive is not
improved, replace
the occupant
detection system
(seat cushion &
frame assembly),
and then the airbag
control module in
this order.

Check the battery
voltage and fuse. If
there is no fault,
replace the airbag
rear harness
together with body
harness.

Step

Check

Yes

No