Subaru Impreza 2003 Service Manual page 2874

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
AIRBAG SYSTEM (DIAGNOSTICS)
Step
1 CHECK PASSENGER'S AIRBAG MODULE.
1)Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2)Remove the glove box.
3)Disconnect the connector (AB27) from (AB4)
4)Connect the connector (1F) in test harness F
to connector (AB4).
5)Connect the airbag resistor to connector (3F)
in test harness F.
6)Connect the battery ground cable and turn
the ignition switch to ON.
2 CHECK AIRBAG MAIN HARNESS.
1)Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2)Disconnect the airbag resistor from the con-
nector (3F) in test harness F.
3)Remove the instrument panel lower cover
and disconnect the connector (AB26) from
(AB21).
4)Disconnect the connector (AB3) from the air-
bag control module, and connect the connector
(1R) in test harness R. <Ref. to AB-16, Airbag
Control Module.>
5)Measure the voltage between connector
(2R) in test harness R and the chassis ground.
Connector & terminal
(2R) No. 3 (+) — Chassis ground ( − − − − ):
(2R) No. 5 (+) — Chassis ground ( − − − − ):
E: DTC 21
DIAGNOSIS:
• 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 more than 20 seconds before starting to work.
• Before replacing the airbag module, seat belt pretensioner roll connector, control module, and
sensor, reconnect each part and confirm that the warning light operates properly.
Step
1 CHECK IF DTC 21 IS INDICATED.
Read the DTC. <Ref. to AB-28, Read Diagnos-
tic Trouble Code (DTC).>
Check
Does the airbag warning light
operate properly?
Is the voltage less than 1 V?
Check
Is the airbag warning light DTC
21 indicated?
AB-48
Yes
Replace the pas- Go to step 2.
senger airbag
module. <Ref. to
AB-13, Passen-
ger's Airbag Mod-
ule.>
Replace the airbag Replace the body
control module. harness with air-
<Ref. to AB-16, bag main harness.
Airbag Control
Module.>
Yes
Replace the airbag Perform clear
control module. memory. <Ref. to
<Ref. to AB-16, AB-30, Clear
Airbag Control Memory Mode.>
Module.>
No
No