check engine light SUBARU LEGACY 1996 Service Manual PDF

B4M0430
7B2
CHECK GENERATOR.
1) Start the engine.
2) Idle the engine.
3) Measure voltage between generator and chassis
ground.
: Terminal
Generator B terminal (+)—Chassis ground
():
Is voltage 10—15 V?
: Go to step7B3.
: Repair generator.
7B3
CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
: Is there poor contact at battery terminal?
: Repair battery terminal.
: Go to step7B4.
B4M0796A
7B4
CHECK POWER SUPPLY OF ABSCM.
1) Disconnect connector from ABSCM.
2) Start engine.
3) Idle the engine.
4) Measure voltage between ABSCM connector and chas-
sis ground.
: Connector & terminal
(F49) No. 28 (+)—Chassis ground ():
Is voltage 10—15 V?
: Go to step7B5.
: Repair ABSCM power supply circuit.
20
4-4cBRAKES [ABS 5.3 TYPE]
7. Diagnostics Chart for ABS Warning Light Circuit and Diagnosis Circuit Failure

B5M0115B
B: ON-BOARD DIAGNOSTIC
When the airbag system is in functioning condition, the
airbag warning light will remain on for 8 seconds and go out
when the ignition switch is set to ON.
If there is any malfunction, the airbag warning light will
either stay on or off continuously. In such cases, perform
on-board diagnostic in accordance with the specified pro-
cedure to determine trouble codes.
1) Turn ignition switch ON (with engine OFF).
2) Connect DIAG. terminal

1to No. 1 terminal of diagno-
sis connector

2located below lower cover.
3) Check in accordance with the trouble code indicated by
the AIRBAG warning light, and record the trouble codes.
4) Turn the ignition switch “OFF” and remove the DIAG.
terminal from No.1 terminal of diagnosis connector.
B5M0116B
C: CLEAR MEMORY
After eliminating problem as per trouble code, clear
memory as follows:
Make sure ignition switch is ON (and engine off). Connect
one DIAG. terminal

1on diagnosis connector
2terminal
No. 1.
While warning light is flashing, connect the other DIAG.
terminal

3on terminal No. 2 for at least three seconds.
After memory is cleared, normal warning light flashing rate
resumes. (Warning light flashes every 0.6 seconds ON-
OFF operation.) Memory cannot be cleared if any problem
exists.
After clear memory and then DIAG. terminals

1and
3,
extract from diagnosis connector

2.
9
5-5SUPPLEMENTAL RESTRAINT SYSTEM
4. Diagnostics Chart for On-board Diagnostic System

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) to
check if warning light goes out. If it does, go to step 4)
below. If it remains on, check body harness and repair if
necessary.
B5M0124A
3) If body harness is satisfactory, replace airbag warning
light module

1. After problem has been eliminated, discon-
nect connectors (3A) and (4A).
G5M0559
4) Turn ignition switch“OFF”, disconnect battery ground
cable and then wait at least 20 seconds, and re-connect
connectors (AB1) and (B31).
5) 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
6) Connect battery ground cable and turn ignition switch
“ON,”(engine off) and connect connectors (6B) and (7B) to
check if warning light goes out. If it does, go to“3.
GROUNDING CIRCUIT INSPECTION”. If it remains on,
replace airbag main harness. After problem has been
eliminated, disconnect connectors (6B) and (7B).
36
5-5SUPPLEMENTAL RESTRAINT SYSTEM
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
O.K.
Not O.K.
Replace fuse No. 15.
2. Body harness inspection
O.K.
Not O.K.
Repair body harness.
3. Airbag warning light module (in combination
meter) inspection
O.K.
Not O.K.
Replace airbag warning light module.
4. Airbag main harness inspection
O.K.
Not O.K.
Replace airbag main harness.
Replace airbag control module.
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
1) Remove and visually check fuse No. 15.
2) If fuse is blown, replace it with a new one. After con-
necting battery cable and turning ignition switch“ON”,ifit
blows again, proceed to“2. BODY HARNESS INSPEC-
TION”.
2. BODY HARNESS INSPECTION
Turn ignition switch“ON”(engine off) to make sure other
warning lights (in combination meter) illuminate. If they do
not, check body harness.




38
5-5SUPPLEMENTAL RESTRAINT SYSTEM
5. Diagnostics Chart with Trouble Code

G5M0461
2. SHOWERING INSPECTION TO BODY
1) Spray water on vehicle body.
CAUTION:
Do not directly spray water on airbag components.
2) Check passenger compartment for traces of leaking.
NOTE:
If leaks are noted, also check wiring harnesses as water
may leak along them and wet airbag connectors.
3. FUSE No. 16, AIRBAG MAIN HARNESS, AIRBAG
CONTROL MODULE, BODY HARNESS APPEARANCE
AND VIBRATION INSPECTION
1) Conduct appearance inspection on fuse No. 16 5-5 [T5L3].>, airbag main harness ,
airbag control module and body
harness.
NOTE:
Also check connectors, terminals, wiring harness and case
for damage.
2) Conduct vibration inspection on fuse No. 16, airbag
main harness, airbag control module and body harness.
NOTE:
Gently shake each part.
G5M0461
4. SHOWERING INSPECTION TO BODY
1) Spray water on vehicle body.
CAUTION:
Do not directly spray water on each part.
2) Check passenger compartment for traces of leaking.
NOTE:
If leaks are noted, check wiring harnesses as water may
leak along them and get parts wet.
5. WARNING LIGHT ILLUMINATION CHECK
Turn ignition switch“ON”(engine off) and observe airbag
warning light.
Airbag warning light comes“ON”for 8 seconds then goes
out and stays out.
44
5-5SUPPLEMENTAL RESTRAINT SYSTEM
5. Diagnostics Chart with Trouble Code

4. Diagnostics Chart for On-board
Diagnostic System
A: BASIC DIAGNOSTICS PROCEDURE
1) Airbag warning light comes “ON”.
2) Turn ignition switch to “ON”, (engine “OFF”) and observe airbag warning light.
3) If airbag warning light stays “ON” after 8 seconds or remains “OFF”, or comes back “ON” after 30 seconds, this indicates a current
problem. Proceed to step 8).
If airbag warning light comes “ON” for 8 seconds, then goes out and stays out, this indicates normal system operation at this time.
Check the memory for intermittent problems by performing the procedure outlined in 5-5b [T4B0] “ON-BOARD DIAGNOSTICS”. Pro-
ceed to step 4).
4) If trouble code indicated, proceed to step 5).
If normal code indicated, proceed to step 6).
5) Repair and replacement, proceed to step 7).
6) Repair and replacement, proceed to step 7).
7) Turn ignition switch “ON”, (engine “OFF”) and observe airbag warning light. If airbag warning light stays “ON” after 8 seconds or
comes back “ON” after 30 seconds, proceed to step 8).
If airbag warning light comes “ON” for 8 seconds, then goes out and stays out, proceed to step 9).
8) Repair and replacement. Proceed to step 10).
9) Clear memory. Proceed to step 10).
10) END
9
5-5bSUPPLEMENTAL RESTRAINT SYSTEM (ELECTRIC SENSOR TYPE)
4. Diagnostics Chart for On-board Diagnostic System

B5M0115B
B: ON-BOARD DIAGNOSTIC
When the airbag system is in functioning condition, the
airbag warning light will remain on for 8 seconds and go out
when the ignition switch is set to ON.
If there is any malfunction, the airbag warning light will
either stay on or off continuously. In such cases, perform
on-board diagnostic in accordance with the specified pro-
cedure to determine trouble codes.
1) Turn ignition switch ON (with engine OFF).
2) Connect DIAG. terminal

1to No. 1 terminal of diagno-
sis connector

2located below lower cover.
3) Check in accordance with the trouble code indicated by
the AIRBAG warning light, and record the trouble codes.
4) Turn the ignition switch“OFF”and remove the DIAG.
terminal from No. 1 terminal of diagnosis connector.
B5M0116B
C: CLEAR MEMORY
After eliminating problem as per trouble code, clear
memory as follows:
Make sure ignition switch is ON (and engine off). Connect
one DIAG. terminal

1on diagnosis connector
2terminal
No. 1.
While warning light is flashing, connect the other DIAG.
terminal

3on terminal No. 2 for at least three seconds.
After memory is cleared, normal warning light flashing rate
resumes. (Warning light flashes every 0.6 seconds ON-
OFF operation.) Memory cannot be cleared if any problem
exists.
After clear memory and then DIAG. terminals

1and
3,
extract from diagnosis connector

2.
10
5-5bSUPPLEMENTAL RESTRAINT SYSTEM (ELECTRIC SENSOR TYPE)
4. Diagnostics Chart for On-board Diagnostic System

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

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