Subaru Legacy IV (2008 year). Manual - part 1037

OD(diag)-13

Control Module I/O Signal

OCCUPANT DETECTION SYSTEM (DIAGNOSTICS)

6. Control Module I/O Signal

A: ELECTRICAL SPECIFICATION

CAUTION:
Never remove the occupant detection control module, occupant detection sensor or seat frame be-
cause they are integrated into one unit.

B: WIRING DIAGRAM

Refer to the electrical wiring diagram. <Ref. to WI-126, WIRING DIAGRAM, Occupant Detection System.>

Terminal name

Terminal 

No.

Input/Output value

Remarks

IG – power supply

9

9 — 16 V

When ignition switch ON

Airbag control module communication

(COM)

10

Open collector terminal

Communication line

Airbag control module communication

(GND)

5

0 V

Ground

Belt tension sensor

(Vcc)

4

0 — 5 V

Belt tension sensor power supply

(Vout)

16

0.5 — 4.5 V

Sensor output voltage

(GND)

14

0 V

Sensor ground

Occupant detection sensor

(Vcc)

6

0 — 5 V

Pressure sensor power supply

(Vout)

7

0.5 — 4.5 V

Sensor output voltage

(GND)

15

0 V

Sensor ground

Buckle switch

1

0 — IG voltage

Ignition voltage when switch ON

Buckle switch

(GND)

2

0 V

Switch ground

OD(diag)-14

Subaru Select Monitor

OCCUPANT DETECTION SYSTEM (DIAGNOSTICS)

7. Subaru Select Monitor

A: OPERATION

1. READ DIAGNOSTIC TROUBLE CODE (DTC)

When malfunction of the airbag system and the occupant detection system occur, the DTC stored in airbag
control module will be read out.
Refer to the READ DIAGNOSTIC TROUBLE CODE (DTC) of the Airbag system (diagnostics). <Ref. to
AB(diag)-24, READ DIAGNOSTIC TROUBLE CODE (DTC), OPERATION, Subaru Select Monitor.>

NOTE:
• For detailed operation procedures, refer to the “PC application help for Subaru Select Monitor”.
• For details concerning DTCs, refer to the List of Diagnostic Trouble Code (Airbag system, Occupant de-
tection system). <Ref. to AB(diag)-38, List of Diagnostic Trouble Code (DTC).> <Ref. to OD(diag)-22, List of
Diagnostic Trouble Code (DTC).>

2. DISPLAY OF STATUS INFORMATION

Check the operating condition of each sensor in the event of malfunction in seat belt buckle switch and seat
position sensor, or when the seat belt buckle switch and seat position sensor has been replaced.
1) On the «Main Menu» display, select the {Each System Check}.
2) On the «System Selection Menu» display, select the {Airbag System}.
3) On the «Airbag System» display, select the {Status Data}.
The following table is for support data.

*1: The seat position is forward.
*2: The seat position is rearward.
*3: Displayed when data other than before and behind the seat, such as the breakdown etc, is input.
*4: Displayed when it is initial.
*5: Seat position sensor not supported
*6: Seat belt fastened
*7: Seat belt not fastened
*8: Displayed when data other than belt fastened or not fastened, such as breakdowns is input.
*9: Seat belt buckle switch not supported
*10: Passenger’s airbag operating state
*11: Passenger’s airbag non-operating state

NOTE:
For detailed operation procedures, refer to the “PC application help for Subaru Select Monitor”.

Item

Display

Seat Position Sensor LH

––

*5

Seat Position Sensor RH

––

*5

Seat Belt Buckle Switch LH

––

*9

Seat Belt Buckle Switch RH

Belted 

*6

/Unbelted

*7

 /Other 

*8

/Initial Setting 

*4

 /––

*9

Passenger’s Airbag control status

ON 

*10

/OFF 

*11

 /Initial Setting 

*4

OD(diag)-15

Subaru Select Monitor

OCCUPANT DETECTION SYSTEM (DIAGNOSTICS)

3. CLEAR MEMORY MODE

Clear the DTC stored in the airbag control module
after repairing the airbag system and occupant de-
tection system. (After the breakdown is recovered,
the breakdown code for completed recoveries are
read out when the next breakdown occurs if the
memory clear work is not performed.)
1) On the «Main Menu» display, select the {Each
System Check}.
2) On the «System Selection Menu» display, select
the {Airbag System}.
3) Select {Clearing Memory} in «Airbag System»
menu screen.
4) When the “Clear Memory?” is shown on the
screen, click the [OK] button.
5) When Done is displayed, terminate the Subaru
Select Monitor and turn the ignition switch to OFF.

NOTE:
For detailed operation procedures, refer to the “PC
application help for Subaru Select Monitor”.

4. SYSTEM CALIBRATION (REZEROING)

NOTE:
When replacing the occupant detection system, or
removing and disassembling the passenger’s seat,
always perform the system calibration after install-
ing a seat in the vehicle.

CAUTION:
When the trouble occurs in the system during
calibration process, “Occupant detection cali-
bration failure” is detected in the DTC 2A of the
airbag system and the airbag warning light
lights. In this case, after turning the ignition
switch to OFF once, redo the system calibration
(Rezeroing), or after clearing the cause of the
failure, perform the system calibration again.
1) Park empty vehicle on a level surface.
2) On the «Main Menu» display, select the {Each
System Check}.
3) On the «System Selection Menu» display, select
the {Occupant Detection System}.
4) On the {Occupant Detection System} display,
select the {Rezeroing}.

5) «See service manual. And check vehicle condi-
tion for successfully completing the rezeroing» is
displayed. Check the following to adjust the condi-
tion of the vehicle.
• Adjust the seat backrest to be fully upright. (For
models with power seats, press the power seat but-
ton until the backrest comes to a stop.)
• Adjust the seat slide position all the way back.
(For models with power seats, press the power
seat button until the seat slide does not move any
further.)
• Do not place anything on the top of the seat
cushion.
• Sit on the seat cushion to smooth the seat sur-
face.
• Check that the passenger’s seat belt is not in-
serted into the buckle, not tense or not stuck.
• Check that ambient temperature is in a range
from 0 to 40°C.
6) When the «Re-zeroing Adjust the passenger
seat to the condition shown in service manual» is
displayed, slide the passenger seat all the way to
the back, check that the backrest is adjusted to all
the way up, and select the [OK].

7) When the «Re-zeroing Unbelt the Passenger
seatbelt Continue: OK, Quit: NO» is displayed,
make sure the passengers seatbelt is disconnected
from the buckle and select the [OK].
8) When the «Re-zeroing Empty the passenger
seat Continue: OK, Quit: NO» is displayed, make
sure that the passengers seat is empty, airbag OFF
indicator illuminates and airbag ON indicator does
not illuminate, and select the [OK].

NOTE:
• After selecting the [OK], «In process...Please
wait for a while..without touching vehicle» is dis-
played. Do not touch or rock the vehicle while the
message is displayed.
• During the system calibration process, if the
«Re-zeroing is unsuccessful See service manual
Press OK to END» is displayed, go to step 10).

OD-00025

OD(diag)-16

Subaru Select Monitor

OCCUPANT DETECTION SYSTEM (DIAGNOSTICS)

9) When the re-zeroing is ended normally, the «Re-
zeroing is successfully completed Press OK to
END» is displayed. And then turn the ignition
switch to OFF to finish the diagnosis.
10) During the system calibration process, if «Re-
zeroing is unsuccessful See service manual Press
OK to END» is displayed, turn the ignition switch to
OFF once and turn it ON again, then read the DTC
of the airbag system. <Ref. to AB(diag)-24, READ
DIAGNOSTIC TROUBLE CODE (DTC), OPERA-
TION, Subaru Select Monitor.>
When DTC is input, fix the fault and then perform
the system calibration. When DTC is not input,
check the seat and vehicle status and then perform
the system calibration again. <Ref. to OD(diag)-15,
SYSTEM CALIBRATION (REZEROING), OPERA-
TION, Subaru Select Monitor.>

NOTE:
When the re-zeroing is unsuccessful, there could
be occupant detection system failure or improper
seat and vehicle status. When the airbag warning
light illuminates, read the DTC of the airbag sys-
tem, and perform the diagnosis while referring to
List of Diagnostic Trouble Code (DTC). <Ref. to
AB(diag)-24, READ DIAGNOSTIC TROUBLE
CODE (DTC), OPERATION, Subaru Select Moni-
tor.> <Ref. to AB(diag)-38, LIST, List of Diagnostic
Trouble Code (DTC).>

B: INSPECTION

1. COMMUNICATION FOR INITIALIZING 
IMPOSSIBLE

DETECTING CONDITION:
Defective harness connector
TROUBLE SYMPTOM:
Communication is impossible between the airbag
control module and the Subaru Select Monitor.
Refer to “COMMUNICATION FOR INITIALIZING
IMPOSSIBLE” in the Airbag system (diagnostics).
<Ref. to AB(diag)-26, COMMUNICATION FOR INI-
TIALIZING IMPOSSIBLE, INSPECTION, Subaru
Select Monitor.>

2. WITHOUT DTC

DETECTING CONDITION:
• Defective combination meter
• Open circuit in harness
TROUBLE SYMPTOM:
• Airbag warning light remains ON.
• “No diagnostic Code Present” will be displayed
on the Subaru Select Monitor.

NOTE:
• For detailed operation procedures, refer to “Air-
bag Warning Light Failure”. <Ref. to AB(diag)-33,
Airbag Warning Light Failure.>
• “No diagnostic Code Present” will be displayed
on the Subaru Select Monitor. is displayed on Sub-
aru Select Monitor, the system is operating proper-
ly.