Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 663

OD(diag)-25

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

OCCUPANT DETECTION SYSTEM (DIAGNOSTICS)

D: DTC 27 ODS COMMUNICATION ERROR

Perform the diagnosis following diagnostic procedures for the airbag system. <Ref. to AB(diag)-69, DTC 27

ODS COMMUNICATION ERROR, Diagnostic Chart with Trouble Code.>

3

CHECK 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 test harness AC from the
belt tension sensor connector (AB56).
3) Connect the test harness AD (1AD) to the
connector (AB56).
4) Disconnect the airbag harness connector
(AB53), and connect connector (1AB) of test
harness AB.
5) Measure the resistance between test har-
ness terminals.

Connector & terminal

(2AB) No. 5 — (2AD) No. 1:
(2AB) No. 4 — (2AD) No. 3:
(2AB) No. 6 — (2AD) No. 2:

Is the resistance less than 10

Ω?

Go to step

4.

Replace the airbag
harness along with
chassis harness.

4

CHECK AIRBAG HARNESS.
Measure the resistance between test harness
terminals, and between test harness terminal
and chassis ground.

Connector & terminal

(2AB) No. 4 — (2AD) No. 1:
(2AB) No. 4 — (2AD) No. 2:
(2AB) No. 4 — chassis ground:
(2AB) No. 5 — (2AD) No. 2:
(2AB) No. 5 — chassis ground:

Is the resistance 1 MΩ or
more?

Go to step

5.

Replace the airbag
harness along with
chassis harness.

5

CHECK AIRBAG HARNESS.
1) Connect the battery ground terminal and
turn the ignition switch to ON.
2) Measure the voltage between test harness
and chassis ground.

Connector & terminal

(2AD) No. 1 (+) — Chassis ground (–):
(2AD) No. 3 (+) — Chassis ground (–):

Is the voltage 1 V or less?

Replace the airbag
harness along with
chassis harness.

Check the seat
harness, and if any
fault is found,
replace the seat
harness. If no fault
is found in the seat
harness, replace
the seat cushion
frame assembly.
<Ref. to SE-8,
PASSENGER’S
SEAT, DISASSEM-
BLY, Front Seat.>

Step

Check

Yes

No

OD(diag)-26

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

OCCUPANT DETECTION SYSTEM (DIAGNOSTICS)

E: DTC 29 ODS FAILURE

DTC DETECTING CONDITION:

• Occupant detection sensor is faulty.

• Occupant detection control module is faulty.

• Occupant detection harness is faulty.

• Rear airbag harness is faulty.

• Fuse No. 25 (in joint box) is blown.

Step

Check

Yes

No

1

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

Is there poor contact?

Reconnect the
connector. If the
fault is not fixed,
replace the airbag
harness.

Go to step

2.

2

CHECK DTC.
Read diagnostic trouble code (DTC) for the air-
bag system.

Is “2C Belt Tension Sensor fail-
ure” or “37 Buckle Switch fail-
ure” displayed in the
diagnostics code?

Perform the diag-
nosis according to
each DTC.

Check the seat
harness, and if any
fault is found,
replace the seat
harness. If the fault
is not fixed, replace
the occupant
detection system.
<Ref. to SE-8,
PASSENGER’S
SEAT, DISASSEM-
BLY, Front Seat.>

OD(diag)-27

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

OCCUPANT DETECTION SYSTEM (DIAGNOSTICS)

F: DTC 37 BUCKLE SWITCH RH FAILURE

DTC DETECTING CONDITION:

• Passenger’s buckle switch circuit is open, shorted or shorted to ground.

• Seat harness circuit is open, shorted or shorted to ground.

• Occupant detection control module is faulty.

WIRING DIAGRAM:

Occupant Detection System <Ref. to WI-87, WIRING DIAGRAM, Occupant Detection System.>

Step

Check

Yes

No

1

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

Is there poor contact?

Reconnect the
connector. If the
fault is not fixed,
replace the airbag
harness.

Go to step

2.

2

CHECK BUCKLE SWITCH.
1) Turn the ignition switch to OFF, disconnect
the battery ground terminal, and wait for 60 sec-
onds.
2) Disconnect the buckle switch connector
(AB60).
3) Connect the test harness AE and test har-
ness Y to buckle switch connector (AB60).
4) Connect the battery ground terminal and
turn the ignition switch to ON.

Does the airbag warning light
illuminate for 6 seconds and go
off?

Replace the buckle
switch. <Ref. to
SB-18, INNER
SEAT BELT
ASSEMBLY,
REMOVAL, Front
Seat Belt.>

Check the seat
harness, and if any
fault is found,
replace the seat
harness. If the fault
is not fixed, replace
the occupant
detection system.

AB60

1 2

1

2

AB60

OD-00075

1

2

AB61

BUCKLE SWITCH

1 2 3 4 5 6 7 8 9

11 12 13 14 15 16 17 18

10

AB61

OCCUPANT DETECTION

CONTROL MODULE

OD(diag)-28

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

OCCUPANT DETECTION SYSTEM (DIAGNOSTICS)