Subaru Impreza 2003 Service Manual page 2916

SEAT BELT SYSTEM
3. Seat Belt Warning System
A: SCHEMATIC
1. LHD MODEL
<Ref. to WI-247, LHD FOR EUROPE MODEL, SCHEMATIC, Seat Belt Warning System.>
2. RHD MODEL
<Ref. to WI-248, RHD FOR EUROPE MODEL, SCHEMATIC, Seat Belt Warning System.>
B: INSPECTION
TROUBLE SYMPTOM:
• Seat belt warning light does not come on or go off.
• Buzzer does not beep.
Step
1 CHECK HARNESS BETWEEN SEAT BELT
TIMER MODULE AND CHASSIS GROUND.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from seat belt
timer module.
3)Measure the resistance between seat belt
timer module harness connector and chassis
ground.
Connector & terminal
(B44) No. 3 — Chassis ground:
2 CHECK POWER SUPPLY OF SEAT BELT
TIMER MODULE.
1)Turn the ignition switch to ON.
2)Measure the voltage between seat belt timer
module connector and chassis ground.
Connector & terminal
(B44) No. 9 (+) — Chassis ground (–):
3 CHECK HARNESS AND SEAT BELT
SWITCH.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from seat belt
timer module.
3)Hold the tang plate disconnected from seat
belt buckle.
4)Measure the resistance between seat belt
timer module harness connector and chassis
ground.
Connector & terminal
(B44) No. 6 — Chassis ground:
4 CHECK SEAT BELT SWITCH AND HAR-
NESS.
1)Turn the ignition switch to OFF.
2)Insert the tang plate into seat belt buckle.
3)Measure the resistance between seat belt
timer module connector and chassis ground.
Connector & terminal
(B44) No. 6 — Chassis ground:
5 CHECK HARNESS BETWEEN SEAT BELT
TIMER MODULE AND SEAT BELT SWITCH.
Measure the resistance of harness between
seat belt timer module connector and seat belt
switch.
Connector & terminal
(B44) No. 6 — (R8) No. 1:
SEAT BELT WARNING SYSTEM
Is the resistance less than 1
Ω?
Is the voltage more than 10 V? Go to step 3.
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is the resistance less than 1
Ω?
SB-8
Check
Go to step 2.
Go to step 4.
Go to step 7.
Go to step 6.
Yes No
Repair the open
circuit of harness
between seat belt
timer module and
chassis ground.
Repair the open
harness, short cir-
cuit and poor con-
tact of connector
between seat belt
timer module and
battery.
Repair the short
circuit of harness
between seat belt
timer module con-
nector and chassis
ground.
Go to step 5.
Repair the open
circuit of harness
and poor contact
of connector
between seat belt
timer module con-
nector and seat
belt switch.