engine SUBARU LEGACY 1996 Service Repair Manual

M: TROUBLE CODE 43
DIAGNOSIS:
Airbag main harness circuit (Driver) is shorted to power
supply.
Airbag module harness (Driver) is shorted to power sup-
ply.
Roll connector is shorted to power supply.
Airbag control module is faulty.
1. Airbag main harness inspection
CAUTION:
Before performing diagnostics on airbag system, turn
ignition switch“OFF”, disconnect battery ground ter-
minal and then wait at least 20 seconds.
After 20 seconds elapse, remove instrument panel
lower cover, and disconnect (AB3) and (AB8), (AB9)
and (AB10).
G5M0559
1. AIRBAG MAIN HARNESS INSPECTION
1) Disconnect connector (AB6) from airbag control module
, and connect it to test harness B2
connector (8B).
2) Connect battery ground cable and turn ignition switch
“ON”(engine off).
3) Measure voltage across each test harness B2 connec-
tor (5B) terminal and chassis ground.
: Connector & terminal
(5B) No. 1 (+)—Chassis ground ():
Is voltage less than 1 V?
: Go to next.
: Replace airbag main harness.
: Connector & terminal
(5B) No. 14 (+)—Chassis ground ():
Is voltage less than 1 V?
: Replace airbag control module.
: Replace airbag main harness.
32
5-5bSUPPLEMENTAL RESTRAINT SYSTEM (ELECTRIC SENSOR TYPE)
5. Diagnostics Chart with Trouble Code

B5M0123B
2. INSPECTION OF BODY HARNESS, CONNECTOR
AND AIRBAG WARNING LIGHT
1) Turn ignition switch“OFF”and connect body harness
connector (B31) to test connector A connector (1A).
G5M0455
2) Connect battery ground cable and turn ignition switch
“ON”, (engine off) and connect connectors (3A) and (4A).
: Does the airbag warning light come off?
: Go to step 3).
: Go to next.
B5M0124A
: Is there anything unusual to body harness?
: Repair body harness.
: Replace airbag warning light module
1.
NOTE:
After problem has been eliminated, disconnect connectors
(3A) and (4A).
G5M0559
3) Turn ignition switch“OFF”, disconnect battery ground
cable and then wait at least 20 seconds, and re-connect
connectors (AB1) and (B31).
4) Remove instrument panel lower cover and disconnect
(AB3) with (AB8), then disconnect connector (AB6) from
airbag control module, and connect
it to test harness B2 connector (8B).
G5M0458
5) Connect battery ground cable and turn ignition switch
“ON,”(engine off) and connect connectors (6B) and (7B).
: Does the airbag warning light come on?
: Go to step3.
: Replace airbag main harness.
NOTE:
After problem has been eliminated, disconnect connectors
(6B) and (7B).
34
5-5bSUPPLEMENTAL RESTRAINT SYSTEM (ELECTRIC SENSOR TYPE)
5. Diagnostics Chart with Trouble Code

O: AIRBAG WARNING LIGHT REMAINS OFF.
DIAGNOSIS:
Fuse No. 15 is blown.
Body harness circuit is open.
Airbag warning light is faulty.
Airbag main harness is faulty.
Airbag control module is faulty.
1. Fuse No. 15 inspection
2. Body harness inspection
3. Airbag warning light module (in combination
meter) inspection
4. Airbag main harness inspection
CAUTION:
Before performing diagnostics on airbag system, turn
ignition switch“OFF”, disconnect battery ground
terminal, and then wait at least 20 seconds.
G5M0460
1. FUSE No. 15 INSPECTION
Remove and visually check fuse No. 15.
: Is fuse No. 15 blown?
: Replace fuse No. 15.
If fuse No. 15 blows again, go to step2.
: Go to step2.
2. BODY HARNESS INSPECTION
Turn ignition switch“ON”(engine off) to make sure other
warning lights (in combination meter) illuminate.
: Do all the warning lights (in combination
meter) except airbag warning light come
on?
: Go to step3.
: Repair body harness.



36
5-5bSUPPLEMENTAL RESTRAINT SYSTEM (ELECTRIC SENSOR TYPE)
5. Diagnostics Chart with Trouble Code

B5M0122B
3. AIRBAG WARNING LIGHT MODULE (IN
COMBINATION METER) INSPECTION
1) Turn ignition switch“OFF”, disconnect battery ground
cable and then wait at least 20 seconds.
2) Disconnect body harness connector (B31) from connec-
tor (AB1).
B5M0124A
3) Connect battery ground cable and turn ignition switch
“ON”(engine off) to make sure airbag warning light illumi-
nates.
: Does the airbag warning light come on?
: Go to step4.
: Replace airbag warning light module
1.
G5M0312
4. AIRBAG MAIN HARNESS INSPECTION
1) Turn ignition switch“OFF”, disconnect battery ground
cable and then wait at least 20 seconds.
2) Connect body harness connector (B31) and connector
(AB1).
3) Disconnect connectors (AB3) and (AB8) below steering
column.
G5M0313
4) Disconnect connector (AB6) from airbag control mod-
ule.
5) Connect battery ground cable and turn ignition switch
“ON”to make sure airbag warning light illuminates.
: Does the airbag warning light come on?
: Replace airbag control module.
: Replace airbag main harness.
37
5-5bSUPPLEMENTAL RESTRAINT SYSTEM (ELECTRIC SENSOR TYPE)
5. Diagnostics Chart with Trouble Code

5. FUSE No. 16, AIRBAG MAIN HARNESS, BODY
HARNESS VIBRATION INSPECTION
Conduct vibration inspection on fuse No. 16, airbag main
harness and body harness.
CAUTION:
Do not shake or vibrate airbag control module.
: Do fuse No. 16, airbag main harness or
body harness malfunction again when shak-
ing?
: Replace faulty airbag component parts.
: Go to step6.
NOTE:
Gently shake each part.
G5M0461
6. SHOWERING INSPECTION TO BODY
Spray water on vehicle body.
CAUTION:
Do not directly spray water on each part.
: Does water leak into the passenger com-
partment when showering vehicle?
: Replace faulty airbag component parts.
: Go to step7.
NOTE:
If leaks are noted, check wiring harnesses as water may
leak along them and get parts wet.
7. WARNING LIGHT ILLUMINATION CHECK
Turn ignition switch“ON”(engine off) and observe airbag
warning light.
: Does the airbag warning light comes on for
8 seconds, then go out and stay out?
: Clear memory.
: Go to 5-5b [T4E0]“DIAGNOSTICS PROCE-
DURE”.
43
5-5bSUPPLEMENTAL RESTRAINT SYSTEM (ELECTRIC SENSOR TYPE)
5. Diagnostics Chart with Trouble Code

5. Control Module I/O Signal
G6M0015
ContentTerminal
No.Measuring conditions and I/O signals (ignition switch ON and engine idling)
Main power supply 2
Battery voltage is present when main power is turned ON.

“0”volt is present when main power is turned OFF.
Inhibitor switch (AT) (U.S.A.)
N position switch (AT) (CANADA)4
“0”volt is present when selector lever is set to P or N position (CANADA: N position only).

Battery voltage is present when selector lever is other than P or N position (CANADA: N
position only).
Air valve 5
“0”volt is present when vehicle is stopped.

ON-and-OFF (“0”-and-battery voltage) operation is alternately repeated while cruise control
is operating.
GND 6—
Vacuum pump motor 7
“0”volt is present when vehicle is stopped.

ON-and-OFF (“0”-and-battery voltage) operation is alternately repeated while cruise control
is operating.
Data link connector 8—
RESUME/ACCEL switch 9
Battery voltage is present when switch is turned ON.

“0”volt is present when switch is turned OFF.
SET/COAST switch 10
Battery voltage is present when switch is turned ON.

“0”volt is present when switch is turned OFF.
Ignition switch 12
Battery voltage is present when ignition switch is turned ON.

“0”volt is present when ignition switch is turned OFF.
Release valve 13
“0”volt is present when vehicle is stopped.

ON-and-OFF (“0”-and-battery voltage) operation is alternately repeated while cruise control
is operating.
Power supply to vacuum pump
motor, air valve, release valve14
“0”volt is present when vehicle is stopped.

Battery voltage is present while cruise control is operating.
Cruise main switch 15
Battery voltage is present during pressing the main switch, and then approx. 12 V is
present while switch is turned ON.

“0”volt is present when switch is turned OFF.
Brake switch 16Turn the cruise main switch to ON and leave clutch pedal released (MT).
Then check that;

“0”volt is present when brake pedal is depressed.

Battery voltage is present when brake pedal is released.
Additionally only in MT vehicle, keep the cruise main switch to ON and leave brake pedal
released.
Then check that;

“0”volt is present when clutch pedal is depressed.

Battery voltage is present when clutch pedal is released.
Data link connector 17—
Data link connector 18—
Vehicle speed sensor 2 19Lift-up the vehicle until all four wheels are raised off ground, and then rotate any wheel manu-
ally.
Approx. 5 and 0 volt pulse signals are alternately input to cruise control module.
Stop light switch 20Turn ignition switch to OFF.
Then check that;

Battery voltage is present when brake pedal is depressed.

“0”volt is present when brake pedal is released.
NOTE:
Voltage at terminals 5, 7, 13 and 14 cannot be checked unless vehicle is driving by cruise control operation.
7
6-2BODY ELECTRICAL SYSTEM
5. Control Module I/O Signal

2. CRUISE CANCEL CONDITIONS DIAGNOSIS
1) Connect select monitor.
2) Start the engine and turn cruise control main switch to
ON.
3) Set select monitor in“FB0”mode.
4) Drive vehicle at least 40 km/h (25 MPH) with cruise
speed set.
5) If cruise speed is canceled itself (without doing any
cancel operations), a trouble code will appear on select
monitor display.
CAUTION:

A trouble code will also appear when cruise cancel
is effected by driver. Do not confuse.

Have a co-worker ride in vehicle to assist in diagno-
sis during driving.
NOTE:
Trouble code will be cleared by turning ignition switch or
cruise control main switch to OFF.
3. REAL-TIME DIAGNOSIS
1) Connect select monitor.
2) Turn ignition switch and cruise control main switch to
ON.
3) Set select monitor in“FA 0”mode.
4) Ensure that normal indication is displayed when con-
trols are operated as indicated below:

When SET/COAST switch is pressed.

When RESUME/ACCEL switch is pressed.

When brake pedal is depressed. (Stop and brake switch
turns ON.)

When clutch pedal is depressed. (MT model)

When select lever is set to N position. (AT model)
10
6-2BODY ELECTRICAL SYSTEM
6. Diagnostics Chart for On-board Diagnosis System

G2M0931
B6M0287
3) Start the engine.
4) Shift on the gear position, and keep the vehicle speed
at constant.
5) Measure signal voltage.
Specified voltage (V): 2 V, or more
NOTE:

If the vehicle speed increases, the width of amplitude
(W) decreases.

If oscilloscope is not available, check input signal
(vehicle speed signal) by using a select monitor. (Refer to
the procedure as described below.)

Using the select monitor:
(1) Set the vehicle on free roller, or lift-up the vehicle and
support with safety stands.
(2) Turn ignition switch to OFF and set select monitor.
(3) Turn ignition switch to ON.
(4) Turn cruise control main switch to ON.
(5) Set select monitor in“F01”or“F02”mode.
(6) Drive the vehicle at speed greater than 40 km/h (25
MPH).
(7) Check that vehicle speed indication on select moni-
tor and speedometer are equal.
NOTE:

When there is a disconnection or short circuit in the har-
ness between the meter and the cruise control module, the
indicated value will be 0 to 1.0 km/h (0 to 0.6 MPH).

In“F01”mode, vehicle speed is indicated in mile per
hour (MPH).
In“F02”mode, vehicle speed is indicated in kilometer per
hour (km/h).
B3M0250
3. PERFORM A CIRCUIT TEST BETWEEN
COMBINATION METER AND CRUISE CONTROL
MODULE.
1) Turn ignition switch to OFF.
2) Remove combination meter.
B6M0194B
3) Disconnect connector from cruise control module.
4) Measure resistance of harness connector between
combination meter and cruise control module.
Connector & terminal / Specified resistance:
(i10) No. 10—(B94) No. 19 / 10Ω, max.
24
6-2BODY ELECTRICAL SYSTEM
8. Diagnostics Chart with Trouble Code

8) The table below lists the nominal sectional areas and
allowable currents of the wires.
Nominal
sectional area
mm
2
No. of strands/
strand diameterOutside
diameter of
finished wiring
mmAllowable
current
Amps/40°C
0.3 7/0.26 1.8 7
0.5 7/0.32 2.2 (or 2.0) 12
0.75 30/0.18 2.6 (or 2.4) 16
0.85 11/0.32 2.4 (or 2.2) 16
1.25 16/0.32 2.7 (or 2.5) 21
2 26/0.32 3.1 (or 2.9) 28
3 41/0.32 3.8 (or 3.6) 38
5 65/0.32 4.6 (or 4.4) 51
8 50/0.45 5.5 67
CAUTION:
When replacing or repairing a wire, be sure to use the
same size and type of the wire which was originally
used.
NOTE:

The allowable current in the above table indicates the
tolerable amperage of each wire at an ambient tempera-
ture of 40°C (104°F).

The allowable current changes with ambient tempera-
ture. Also, it changes if a bundle of more than two wires is
used.
G6M0203
9) Each unit is directly grounded to the body or indirectly
grounds through a harness ground terminal. Different sym-
bols are used in the wiring diagram to identify the two
grounding systems.
The ground points shown in the wiring diagram refer to the
following:
GBBody ground
GEEngine ground
GRRadio ground
GDRear defogger ground
All wiring harnesses are provided with a ground point which
should be securely connected.
5
6-3WIRING DIAGRAM
1. General Description

G6M0205
11) Each connector number shown in the wiring diagram
corresponds to that in the wiring harness. The location of
each connector in the actual vehicle is determined by read-
ing the first character of the connector (for example, a“F”
for F8,“i”for i16, etc.) and the type of wiring harness.
The first character of each connector number refers to the
area or system of the vehicle, as indicated in table below.
Symbol Wiring harness and Cord
F Front wiring harness
B Bulkhead wiring harness
E Engine wiring harness
T Transmission cord
D Door cord LH & RH, Rear gate cord
I Instrument panel wiring harness
RRear wiring harness, Rear defogger cord
Room light cord,
Fuel tank cord,
Sunroof cord,
Trunk lid cord
P Floor wiring harness
7
6-3WIRING DIAGRAM
1. General Description