Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 644

AB(diag)-115

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

CHECK DRIVER’S AIRBAG MODULE.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait for 60 sec-
onds or more.
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 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 six seconds and
go off?

Replace the
driver’s airbag
module. <Ref. to
AB-15, Driver’s Air-
bag Module.>

Go to step

CHECK ROLL CONNECTOR.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait for 60 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 six seconds and
go off?

Replace the roll
connector. <Ref. to
AB-26, Roll Con-
nector.>

Go to step

CHECK AIRBAG MAIN HARNESS (DRIV-
ER’S AIRBAG HARNESS).
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait for 60 sec-
onds or more.
2) Disconnect the airbag resistor from the con-
nectors (2P) and (3P) of test harness P.
3) Remove the console front panel and discon-
nect the connector (AB9).
4) Disconnect the connectors (AB6, AB17,
AB18) from the airbag control module, and con-
nect the connector (1AH) in the test harness
AH.
5) Connect the connector (2AH) in the test har-
ness AH and the connector (1AG) in the test
harness AG.
6) Connect the battery ground terminal and
turn the ignition switch to ON.
7) Measure the voltage between connector
(3AG) in the test harness AG and chassis
ground.

Connector & terminal

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

Is the voltage less than 1 V?

Go to step

Replace the airbag
main harness
along with body
harness.

Step

Check

Yes

AB(diag)-116

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

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-21,
Airbag Control
Module.>

Go to step

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)-39, List
of Diagnostic Trou-
ble Code (DTC).>

Finish the diagno-
sis.

Step

Check

Yes

AB(diag)-117

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

BB:DTC 76 PASSENGER’S AIRBAG FAILURE

DTC DETECTING CONDITION:

• Airbag main harness circuit (passenger’s side) is shorted to power supply.

• Airbag module harness circuit (passenger’s side) 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 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.
NOTE:

Prior to starting work, prepare two AIRBAG RESISTORs (98299PA040).

WIRING DIAGRAM:

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

Step

Check

Yes

CHECK POOR CONTACT OF CONNEC-
TORS.
Check for poor contact of the connectors
between the airbag control module and the pas-
senger’s airbag module.

Is there poor contact?

Replace the airbag
main harness
along with body
harness.

Go to step

CHECK PASSENGER’S AIRBAG MODULE.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait for 60 sec-
onds or more.
2) Remove the console front panel and discon-
nect the connector (AB9).
3) Connect the connector (1P) in the test har-
ness P to connector (AB9).
4) Connect the airbag resistor to the connec-
tors (2P) and (3P) of test harness P.
5) Connect the battery ground terminal and
turn the ignition switch to ON.

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

Replace the pas-
senger’s airbag
module. <Ref. to
AB-16, Passen-
ger’s Airbag Mod-
ule.>

Go to step

1 2 3 4

18 19 20

21 22 23 24 25 26 27 28

1 2 3

5 6 7 8

11 12 13 14

16 17

29 30

AB9

AB6

AB9

AB6

AB-02488

AIRBAG CM

PASSENGER'S AIRBAG MODULE

AB(diag)-118

Diagnostic Chart with Trouble Code

AIRBAG SYSTEM (DIAGNOSTICS)

CHECK AIRBAG MAIN HARNESS (PASSEN-
GER’S AIRBAG HARNESS).
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait for 60 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 lower cover
and disconnect the connector (AB7) from
(AB2).
4) Disconnect the connectors (AB6, AB17,
AB18) from the airbag control module, and con-
nect the connector (1AH) in the test harness
AH.
5) Connect the connector (2AH) in the test har-
ness AH and the connector (1AG) in the test
harness AG.
6) Measure the voltage between connector
(3AG) in the test harness AG and chassis
ground.