2004 SUBARU FORESTER replace disc

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-59
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK AIRBAG CONTROL MODULE.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Disconnect the connector (AB3) from the
airbag control module. Control Module.>
3) Connect the connector (1R) in test harness
R to connector (AB3).
4) Connect the battery ground cable and turn
the ignition switch to ON.
5) Measure the voltage between connector
(2R) in test harness R and chassis ground.
Connector & terminal
(2R) No. 1 (+) — Chassis ground (
−): Is the voltage more than 10 V? Replace the airbag
control module.
Airbag Control
Module.>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 connector (AB1)
from the body harness (B31).
3) Connect the connector (2M) in test harness
M to connector (AB1).
4) Measure the resistance between connector
(5M) in test harness M and the connector (2R)
in test harness R.
Connector & terminal
(5M) No. 2 — (2R) No. 1: Is the resistance less than 10
Ω?Go to step 3.Replace the airbag
main harness with
body harness.
3 CHECK AIRBAG MAIN HARNESS.
Measure the following resistance with the
above-mentioned condition maintained.
Connector & terminal
(5M) No. 2 — Chassis ground:
(2R) No. 1 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 4.Replace the airbag
main harness with
body harness.
4 CHECK FUSE No. 11 (IN JOINT BOX).
1) Confirm that the ignition switch is turned
OFF.
2) Remove the fuse No. 11 (in fuse and relay
box) and perform visual inspection.Is the fuse No. 11 blown out? Replace the fuse
No. 11. If fuse No.
11 blows out
again, repair the
body harness. Repair the body
harness.

AB-61
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK AIRBAG CONTROL MODULE.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Disconnect the connector (AB3) from the
airbag control module. Control Module.>
3) Connect the connector (1R) in test harness
R to connector (AB3).
4) Connect the battery ground cable and turn
the ignition switch to ON.
5) Measure the voltage between connector
(2R) in test harness R and chassis ground.
Connector & terminal
(2R) No. 1 (+) — Chassis ground (
−): Is the voltage more than 10 V? Replace the airbag
control module.
Airbag Control
Module.>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 connector (AB1)
from the body harness (B31).
3) Connect the connector (2M) in test harness
M to connector (AB1).
4) Measure the resistance between connector
(5M) in test harness M and the connector (2R)
in test harness R.
Connector & terminal
(5M) No. 9 — (2R) No. 1: Is the resistance less than 10
Ω?Go to step 3.Replace the airbag
main harness with
body harness.
3 CHECK AIRBAG MAIN HARNESS.
Measure the following resistance with the
above-mentioned condition maintained.
Connector & terminal
(5M) No. 9 — Chassis ground:
(2R) No. 1 — Chassis ground: Is the resistance more than 1
MΩ? Go to step 4.Replace the airbag
main harness with
body harness.
4 CHECK FUSE No. 11 (IN FUSE AND RELAY
BOX).
1) Confirm that the ignition switch is turned
OFF.
2) Remove the fuse No. 11 (in fuse and relay
box) and perform visual inspection.Fuse No. 11 is not blown out. Replace the fuse
No. 11. If fuse No.
11 blows out
again, repair the
body harness. Repair the body
harness.

AB-63
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK AIRBAG CONTROL MODULE.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Disconnect the connector (AB3) from air-
bag control module. Control Module.>
3) Connect the connector (1R) in test harness
R to connector (AB3).
4) Connect the battery ground cable, and turn
the ignition switch to ON.
5) Measure the voltage between the connec-
tor (2R) in test harness R and the chassis
ground.
Connector & terminal
(2R) No. 6 (+) — Chassis ground (
−): Is the voltage more than 10 V? Replace the airbag
control module.
Airbag Control
Module.>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 connector (AB1)
from the body harness (B31).
3) Connect the connector (2M) in test harness
M to the airbag connector (AB1).
4) Measure the resistance between the con-
nector (5M) in test harness M and the connec-
tor (2R) in test harness R.
Connector & terminal
(5M) No. 4 — (2R) No. 6: Is the resistance less than 10
Ω?Go to step 3.Replace the airbag
main harness with
body harness.
3 CHECK AIRBAG MAIN HARNESS.
Measure the following resistance with the
above-mentioned condition maintained.
Connector & terminal
(5M) No. 4 — Chassis ground:
(2R) No. 6 — Chassis ground: Is the resistance more than 1
MΩ?Go to step 4.Replace the airbag
main harness with
body harness.
4 CHECK FUSE NO. 6 (IN FUSE AND RELAY
BOX).
1) Confirm that the ignition switch is turned
OFF.
2) Remove the No. 6 fuse (in fuse and relay
box) and perform visual inspection.Is the fuse No. 6 blown out? Replace the fuse
No. 6. If fuse No. 6
is blown out again,
repair the body
harness. Repair the body
harness.

AB-65
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK AIRBAG CONTROL MODULE.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Disconnect the connector (AB3) from air-
bag control module. Control Module.>
3) Connect the connector (1R) in test harness
R to connector (AB3).
4) Connect the battery ground cable, and turn
the ignition switch to ON.
5) Measure the voltage between the connec-
tor (2R) in test harness R and the chassis
ground.
Connector & terminal
(2R) No. 6 (+) — Chassis ground (
−): Is the voltage more than 10 V? Replace the airbag
control module.
Airbag Control
Module.>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 connector (AB1)
from the body harness (B31).
3) Connect the connector (2M) in test harness
M to the airbag connector (AB1).
4) Measure the resistance between the con-
nector (5M) in test harness M and the connec-
tor (2R) in test harness R.
Connector & terminal
(5M) No. 4 — (2R) No. 6: Is the resistance less than 10
Ω?Go to step 3.Replace the airbag
main harness with
body harness.
3 CHECK AIRBAG MAIN HARNESS.
Measure the following resistance with the
above-mentioned condition maintained.
Connector & terminal
(5M) No. 1 — Chassis ground:
(2R) No. 6 — Chassis ground: Is the resistance more than 1
MΩ? Go to step 4.Replace the airbag
main harness with
body harness.
4 CHECK FUSE NO. 6 (IN FUSE AND RELAY
BOX).
1) Confirm that the ignition switch is turned
OFF.
2) Remove the No. 6 fuse (in fuse and relay
box) and perform visual inspection.Is the fuse No. 6 blown out? Replace the fuse
No. 6. If fuse No. 6
is blown out again,
repair the body
harness. Repair the body
harness.

AB-67
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK FRONT SUB-SENSOR (RH) AND
AIRBAG HARNESS.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Disconnect the connector (AB3) from the
airbag control module, and connect the con-
nector (1R) in test harness R. Airbag Control Module.>
3) Measure the resistance of the connector
(3R) in test harness R.
Connector & terminal
(3R) No. 7 — (3R) No. 9: Is the resistance 750 Ω and 1
KΩ? Replace the airbag
control module.
Airbag Control
Module.>Go to step 2.
2 CHECK AIRBAG MAIN HARNESS AND
FRONT SUB-SENSOR HARNESS (RH).
1) Disconnect the connector (AB15) from the
front sub-sensor. Sensor.>
2) Connect the connector (IH) in test harness
H to connector (AB15).
3) Measure the resistance between connector
(3R) in test harness R and connector (3H) in
test harness H.
Connector & terminal
(3R) No. 7 — (3H) No. 5:
(3R) No. 9 — (3H) No. 6: Is the resistance less than 10
Ω?Go to step 3.LHD model:
Replace the airbag
main harness and
front sub-sensor
harness with body
harness.
RHD model:
Go to step 4.
3 CHECK AIRBAG MAIN HARNESS AND
FRONT SUB-SENSOR HARNESS (RH).
Measure the resistance between connector
(3R) in test harness R and the chassis ground.
Connector & terminal
(3R) No. 7 — Chassis ground:
(3R) No. 9 — Chassis ground: Is the resistance more than 1
MΩ?Go to step 8.LHD model:
Replace the airbag
main harness and
front sub-sensor
harness with body
harness.
RHD model:
Go to step 4.
4 CHECK AIRBAG MAIN HARNESS
1) Disconnect the connector (AB13) from
(AB14), and connect the connector (1L) in test
harness L to connector (AB13).
2) Measure the resistance between connector
(3R) in test harness R and connector (3L) in
test harness L.
Connector & terminal
(3R) No. 7 — (3L) No. 4:
(3R) No. 9 — (3L) No. 3: Is the resistance less than 10
Ω?Go to step 5.Replace the airbag
main harness with
body harness.
5 CHECK AIRBAG MAIN HARNESS
Measure the resistance between connector
(3R) in test harness R and the chassis ground.
Connector & terminal
(3R) No. 7 — Chassis ground:
(3R) No. 9 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 6.Replace the airbag
main harness with
body harness.
6 CHECK FRONT SUB-SENSOR HARNESS
(RH).
1) Connect the connector (2L) in test harness
F to the connector (AB14).
2) Measure the resistance between connector
(3H) in test harness H and connector (3L) in
the test harness L.
Connector & terminal
(3L) No. 5 — (3H) No. 5:
(3L) No. 6 — (3H) No. 6: Is the resistance less than 10
Ω?Go to step 7.Replace the front
sub-sensor har-
ness (RH) with
body harness.

AB-70
AIRBAG SYSTEM (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK FRONT SUB-SENSOR (LH) AND
AIRBAG HARNESS.
1) Turn the ignition switch to OFF, disconnect
the battery ground cable, and wait more than
20 seconds.
2) Disconnect the connector (AB3) from the
airbag control module, and connect connector
(1R) in the test harness R to connector (AB3).

3) Measure the resistance of the connector
(3R) in the test harness R.
Connector & terminal
(3R) No. 6 — (3R) No. 8: Is the resistance 750 Ω and 1
KΩ?Replace the airbag
control module.
Airbag Control
Module.>Go to step 2.
2 CHECK AIRBAG MAIN HARNESS AND
FRONT SUB-SENSOR HARNESS (LH).
1) Disconnect the connector (AB18) from the
front sub-sensor. Sensor.>
2) Connect the connector (1H) in test harness
H to connector (AB18).
3) Measure the resistance between connector
(3R) in test harness R and connector (3H) in
test harness H.
Connector & terminal
(3R) No. 6 — (3H) No. 5:
(3R) No. 8 — (3H) No. 6: Is the resistance less than 10
Ω?Go to step 3.LHD model:
Go to step 4.
RHD model:
Replace the airbag
main harness and
front sub-sensor
harness with body
harness.
3 CHECK AIRBAG MAIN HARNESS AND
FRONT SUB-SENSOR HARNESS (LH).
Measure the resistance between connector
(3R) in test harness R and the chassis ground.
Connector & terminal
(3R) No. 6 — Chassis ground:
(3R) No. 8 — Chassis ground: Is the resistance more than 1
MΩ?Go to step 8.LHD model:
Go to step 4.
RHD model:
Replace the airbag
main harness and
front sub-sensor
harness with body
harness.
4 CHECK AIRBAG MAIN HARNESS
1) Disconnect the connector (AB13) from
(AB14), and connect the connector (1L) in test
harness L to connector (AB13).
2) Measure the resistance between connector
(3R) in test harness R and connector (3L) in
test harness L.
Connector & terminal
(3R) No. 6 — (3L) No. 4:
(3R) No. 8 — (3L) No. 3: Is the resistance less than 10
Ω?Go to step 5.Replace the airbag
main harness with
body harness.
5 CHECK AIRBAG MAIN HARNESS
Measure the resistance between connector
(3R) in test harness R and the chassis ground.
Connector & terminal
(3R) No. 6 — Chassis ground:
(3R) No. 8 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 6.Replace the airbag
main harness with
body harness.
6 CHECK FRONT SUB-SENSOR HARNESS
(LH).
1) Connect the connector (2L) in test harness
L to the connector (AB14).
2) Measure the resistance between connector
(3H) in test harness H and connector (3L) in
the test harness L.
Connector & terminal
(3L) No. 5 — (3H) No. 5:
(3L) No. 6 — (3H) No. 6: Is the resistance less than 10
Ω?Go to step 7.Replace the front
sub-sensor har-
ness (LH) with
body harness.