check engine SUBARU LEGACY 1995 Service Repair Manual

B4M0743
1. CHECK ENGINE TROUBLE CODE.
1) Read out engine trouble code.
2) Is trouble code 39 in memory?
B4M0395A
2. CHECK INPUT VOLTAGE OF ABS/TCS CONTROL
MODULE.
1) Turn ignition switch OFF.
2) Disconnect ABS/TCS control module connectors.
3) Turn ignition switch ON, while engine is idling.
4) Measure voltage between ABS/TCS control module
connector and body.
Connector & terminal / Specified voltage:
(P5) No. 1—body / 14.5±0.3 V
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8. Diagnostics Chart with Trouble Code

B4M0733A
3. CHECK GROUND SHORT OF HARNESS.
1) Turn ignition switch OFF.
2) Remove No. 18 fuse from fuse and joint box.
3) Disconnect ABS/TCS control module connectors.
4) Measure resistance between ABS/TCS control module
connector and body.
Connector & terminal / Specified resistance:
(P5) No. 1—body/1MΩor more
B4M0405A
4. CHECK GROUND CIRCUIT OF ABS/TCS CONTROL
MODULE.
1) Turn ignition switch OFF.
2) Disconnect connector from ABS/TCS control module.
3) Measure resistance between ABS/TCS control module
connector and body.
Connector & terminal / Specified resistance:
(P4) No. 6—body / 1Ωor less
(P5) No. 5—body / 1Ωor less
(P7) No. 15—body / 1Ωor less
5. CHECK GENERATOR FUNCTION.
1) When the ignition key is at OFF, check the charge warn-
ing light is off.
2) Turn the key ON and ensure the light comes on.
3) Keep the engine running at idle and ensure the light
goes off.
B4M0473A
B4M0395A
6. CHECK INPUT VOLTAGE OF ABS/TCS CONTROL
MODULE.
1) Turn ignition switch OFF.
2) Disconnect ABS/TCS control module connectors.
3) Turn ignition switch ON.
4) Measure voltage between ABS/TCS control module
connector and body.
Connector & terminal / Specified voltage:
(P7) No. 20—body/2Vorless (Engine OFF)
(P7) No. 20—body / 10—14 V (Engine idling)
(P5) No. 1—body / 10—13 V (Engine OFF)
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8. Diagnostics Chart with Trouble Code

B4M0521
V: TROUBLE CODE 43
EGI LINE
—Faulty engine control module communication
cables—
DIAGNOSIS:

AET communication cable is broken or short circuited.

AEB communication cable is broken or short circuited.

AEC communication cable is broken or short circuited.

Faulty ABS/TCS control module

Faulty engine control module
TROUBLE SYMPTOM:

TCS does not operate.
1. Check communication cables.

OK

Terminal voltage
remains at 4—5.4 V.
Replace ABS/TCS control module.

Terminal voltage
remains at 10—14 V.
Go to step 2.

Terminal voltage
remains at2Vorless.
Go to step 4.
Replace ABS/TCS control module.
2. Check harness between ABS/TCS control
module and ECM.

OK
Not OK
Repair harness.
3. Check ABS/TCS control module internal
circuits.

OK
Not OK
Replace ABS/TCS control module.
Replace engine control module.
4. Check output voltage of ECM.

Not OK
OK
6. Check open circuit of harness.
OK Not OK
Replace ABS/TCS
control module.
5. Check body short of harness.

OK
Not OK
Repair harness/connector.
Replace engine control module.






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10. Diagnostic Chart with Select Monitor

11. General Diagnostics Table
: Primary expected causes: Secondary expected causes
Trouble conditions
SymptomsHydraulic
unit
Speed sensor
P valve
Master cylinder
Calipers and piston
Pad
Rotor
Hand brake
Piping
Mixture of air
Brake booster and check valve
Axle and wheel
Alignment
Play of pedal
Rough road surface
Semicylindrical road surface
Loose or worn suspension
Tire
Wrong connection and wiring
Stroke sensor Solenoid valve
Motor
Mount bush ABS function
Directional stability cannot be
obtained when braking.Vehicle turns to right or left. 
Vehicle spins.
Out-of-order brakesLong braking distance
 
Brakes lock.  
Brakes drag.
Long pedal stroke  
Abnormal vehicle pitching 
Unstable braking force. One-
side brake refuses to work. 
TCS function
When accelerating abruptly,
directional stability cannot be
obtained when traveling on a
slippery road surface.Vehicle moves unsteadily.
Handle refuses to work.
Handle loses control. 
Bad acceleration, engine stall-
ing (In addition to the causes
listed here, check the ECM
specifications.)Engine stalls. Engine speed
fails to increase.
Engine speed increases sud-
denly.
Vibration occurs and abnormal
noise is produced.

When applying brakes abruptly.

When accelerating abruptly.

When driving on a slippery
road surface.Brake pedal heavily vibrates
when applying brakes.
   
Loud hydraulic unit operating
noise
Noise is produced from front
of vehicle.
Noise is produced from rear of
vehicle.
NOTE:
This list includes no engine failure and transmission failure.
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11. General Diagnostics Table

12. Phenomena Peculiar to the System
1. WHEN TRAVELING WITH EXTREMELY UNDER
INFLATED TIRES
The TCS is apt to operate (particularly when turning) and,
when it operates, acceleration can become slow*. This
state is not abnormal. Immediately restore the tires to nor-
mal by traveling after releasing the TCS with the TCS OFF
switch.
* Poor acceleration is sometimes caused by the engine
itself. Check whether or not the TCS operating indicator
light (green) comes on to determine that the failure is
caused by the TCS control.
2. WHEN THE T TIRES ARE FITTED
The TCS is apt to operate (particularly when turning) and,
when it operates, acceleration can become slow. This state
is not abnormal. Immediately restore the tires to normal by
traveling after releasing the TCS with the TCS OFF switch.
3. WHEN OPERATING THE TCS CONTINUOUSLY ON
A SLOPE IMPOSSIBLE TO CLIMB OR IN STACK
S TAT E
When operating the TCS for a long time, it can be auto-
matically turned off (the OFF indicator light will come on),
stopping braking. This state is not abnormal. It automati-
cally resets by stopping and leaving the vehicle.
4. WHEN HEAVY LOAD IS PLACED ON THE BRAKES
If service brakes are used too often when descending a
long slope, heavy load can be placed on the brakes. To
prevent this problem, the TCS is automatically turned off
(the OFF indicator light will come on). This state is not
abnormal. Stop the vehicle and leave it in the same way as
step 3, it automatically resets.
5. KICKBACK TO THE BRAKE PEDAL WHEN THE
ABS IS OPERATING
Compared with ABS of the AWD model system, pedal kick-
back with large amplitude of vibration and long cycle can
be felt. This is caused by the difference in system configu-
ration and, therefore, not abnormal. If you receive an
inquiry from your clients, fully explain this point.
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12. Phenomena Peculiar to the System

6. INSPECTOR
Before advancing the vehicle after the engine starts, drive
the pump motor and valve for a very short time to function-
ally check the ABS/TCS brakes. It is not abnormal if, at this
time, operating noises of the valve and motor are produced
or kickback of the brake pedal is felt when stepping on the
pedal.
7. WHEN ATTACHING CHAINS
It is sometimes a good idea to turn off the TCS for better
advancing and accelerating the vehicle.
8. WHEN A DRUM TESTER IS USED (SPEEDOMETER
TEST, EXHAUST GAS TEST, BRAKE TEST, ETC.)
Before performing tests, turn the TCS off by operating the
TCS OFF switch or disconnect the fuse of ECM input
power source to put the machine out of operation. If oper-
ating other parts to put the TCS in the fail state
intentionally, trouble code will be recorded. Make sure to
clear the memory. Also, in a 2-wheel tester, wheel speed
sensor failure can be detected, making the TCS fail. This
case is also not abnormal and clearing the memory is
required.
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12. Phenomena Peculiar to the 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.
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4. Diagnostics Chart for On-board Diagnostic System

G5M0559
1. AIRBAG CONTROL MODULE 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 connector (5B) terminal and
body.
(5B) Terminal / Specified voltage:
No. 5—Body / 10 V, or more
2. AIRBAG MAIN HARNESS INSPECTION
1) Go to step 2) below after performing diagnostics on air-
bag system as per flowchart under“1. AIRBAG CON-
TROL MODULE INSPECTION”previously outlined.
2) Turn ignition switch“OFF”, disconnect battery ground
cable and then wait at least 20 seconds.
B5M0119B
3) Disconnect connector (AB1) from body harness con-
nector (B31) at front lower pillar, and connect connector
(AB1) to test harness A connector (2A).
4) Measure resistance between test harness A connector
(5A) and test harness B2 connector (5B) terminals.
Connector & terminal / Specified resistance:
(5A) No. 9—(5B) No.5/10Ω, or less
5) Measure resistance between each terminal of connec-
tors (5A) and (5B) and body.
(5A) Terminal / Specified resistance:
No. 9—Body/10kΩ, or more
(5B) Terminal / Specified resistance:
No. 5—Body/10kΩ, or more
G5M0453
3. FUSE No. 16 INSPECTION
Make sure ignition switch is turned“OFF”, then remove and
visually check fuse No. 16.
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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) 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).
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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.




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