2004 SUBARU FORESTER light

AB-51
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK DRIVERS AIRBAG MODULE.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Remove the driver’s airbag module. to AB-14, Driver’s Airbag Module.>
3) Connect the connector (AB2) to connector
(1N) in test harness N.
4) Connect the airbag resistor to connector
(2N) in test harness N.
5) Connect the battery ground cable and turn
the ignition switch to ON.Is the airbag warning light
turned on normally?Replace the
driver’s airbag
module. AB-14, Driver’s
Airbag Module.>Go to step 2.
2 CHECK ROLL CONNECTOR.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Disconnect the test harness N from the
connector (AB2).
3) Remove the instrument panel lower cover
and disconnect the connector (AB21) from
(AB26).
4) Connect the connector (1F) in test harness
F to connector (AB21).
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.Is the airbag warning light
turned on normally?Replace the roll
connector. AB-20, Roll Con-
nector.>Go to step 3.
3 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
connector (3F) in test harness F.
3) Remove the glove box, and disconnect the
connectors (AB4) and passenger’s airbag
module (AB27).
4) Disconnect the connector (AB3) from the
airbag control module, and connect the con-
nector (1R) in test harness R. Airbag Control Module.>
5) Connect the battery ground cable and turn
the ignition switch to ON. (engine OFF)
6) Measure the voltage between connector
(2R) in test harness R and the chassis ground.
Connector & terminal
(2R) No. 2 (+) — Chassis ground (
−):
(2R) No. 4 (+) — Chassis ground (
−): Is the voltage less than 1 V? Replace the airbag
control module.
Airbag Control
Module.>Replace the airbag
main harness with
body harness.

AB-52
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
D: DTC 16
DIAGNOSIS:
 Airbag main harness circuit (Passenger) is shorted to the power supply.
 Airbag module harness (Passenger) is shorted to the 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 more than 20 seconds before starting to work.
 After replacing the airbag module, seat belt pretensioner, roll connector, control module or sensor,
reconnect each part and confirm that the airbag warning light operates properly.
 When inspecting the airbag main harness, disconnect the airbag module connector of the driver
and passenger seats for safety reasons.
WIRING DIAGRAM:
AB-00742
AB3 INFLATOR
(PASSENGER SIDE)
AB4
AB4
AB27
11
10 3
47
8
1
2
AIRBAG CONTROL MODULEAB3
12341234567891011121314151617
1819202122232425262728

AB-53
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK PASSENGERS 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 passenger’s airbag connec-
tor (AB27) and (AB4).
4) Connect the connector (1P) in test harness
P to connector (AB4).
5) Connect the airbag resistor to connector
(2P), (3P) in test harness P.
6) Connect the battery ground cable and turn
the ignition switch to ON. Is the airbag warning light
turned on normally?Replace the pas-
senger airbag
module. AB-15, Passen-
ger’s Airbag Mod-
ule.>Go to step 2.
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
connector in test harness P.
3) Remove the instrument panel lower cover
and disconnect the connector (AB21) from
(AB26).
4) Disconnect the connector (AB3) from the
airbag control module, and connect the con-
nector (1R) in test harness R. Airbag Control Module.>
5) Connect the battery ground cable and turn
the ignition switch to ON.
6) 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 (
−): Is the voltage less 1 V? Replace the airbag
control module.
Airbag Control
Module.>Replace the airbag
main harness with
body harness.

AB-54
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
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.
 After replacing the airbag module, seat belt pretensioner, roll connector, control module or sensor,
reconnect each part and confirm that the airbag warning light operates properly.
Step Check Yes No
1 CHECK IF DTC 21 IS INDICATED.
Read the DTC. tic Trouble Code (DTC).>Is the airbag warning light DTC
21 indicated?Replace the airbag
control module.
Airbag Control
Module.>Perform the clear
memory mode.
Clear Memory
Mode.>

AB-57
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
G: DTC 23
DIAGNOSIS:
(AB3), (AB7) and (AB8) are not connected properly to airbag control module.
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.
Step Check Yes No
1 CHECK POOR CONTACT IN CONECTORS
(AB3), (AB7) AND (AB8).
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Disconnect the connectors (AB3), (AB7)
and (AB8) from the airbag control module.
Check if rust or damage
appear on the harness con-
nector and the control module
connector.Replace the airbag
control module.
Airbag Control
Module.> Replace
the airbag main
harness with body
harness.Replace
the side airbag
harness with body
harness.Go to step 2.
2 CHECK POOR CONTACT IN CONECTORS
(AB3), (AB7) and (AB8).
1) Ensure that connectors are firmly recon-
nected.
2) Connect the battery ground cable and turn
the ignition switch to ON.Is the airbag warning light
turned on normally? Finish the diagno-
sis.Replace the airbag
control module.
Airbag Control
Module.>

AB-58
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
H: DTC 24
DIAGNOSIS:
 Airbag control module is faulty.
 Airbag main harness circuit is open.
 Fuse No. 11 (in fuse and relay box) is blown.
 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 more than 20 seconds before starting to work.
 After replacing the airbag module, seat belt pretensioner, roll connector, control module or sensor,
reconnect each part and confirm that the airbag warning light operates properly.
 When inspecting the airbag main harness, disconnect the driver’s airbag module and passenger’s
airbag module connectors for safety reasons.
1. LHD MODEL
WIRING DIAGRAM:
AB-00623
AB3
AIRBAG CONTROL MODULEAB3
B31
AB1
AB1
1
6
BATTERY
IG SW
NO.11
B31
12
34561
23 45 61234567891011121314151617
1819202122232425262728

AB-62
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
I: DTC 25
DIAGNOSIS:
 Airbag control module is faulty.
 Airbag main harness circuit is open.
 Fuse No. 6 (in joint box) is blown.
 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 more than 20 seconds before starting to work.
 After replacing the airbag module, seat belt pretensioner, roll connector, control module or sensor,
reconnect each part and confirm that the airbag warning light operates properly.
 When inspecting the airbag main harness, disconnect the driver’s airbag module and passenger’s
airbag module connectors for safety reasons.
1. LHD MODEL
WIRING DIAGRAM:
AB-00624
AB3
AIRBAG CONTROL MODULEAB3
B31
AB1
AB1
2
5
BATTERY
IG SW
NO.6
B31
12
34561
23 45 61234567891011121314151617
1819202122232425262728

AB-66
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
J: DTC 31
DIAGNOSIS:
 Front sub-sensor harness circuit (RH) is shorted, open or shorted to power supply.
 Airbag main harness circuit is shorted, open or shorted to power supply.
 Front sub-sensor (RH) 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 more than 20 seconds before starting to work.
 After replacing the airbag module, seat belt pretensioner, roll connector, control module or sensor,
reconnect each part and confirm that the airbag warning light operates properly.
 When inspecting the airbag main harness, disconnect the driver’s airbag module and passenger’s
airbag module connectors for safety reasons.
WIRING DIAGRAM:
AB-00747
AB3
AB13
AB14
AB15
AB3
LHD
RHD
LHD
RHD
LHD
FRONT SUB SENSOR RH
209
21
RHD
LHDRHD
AB13AB15
1212
AIRBAG CONTROL MODULE
1
2
1234567891011121314151617
1819202122232425262728