sensor SUBARU LEGACY 1995 Service Repair Manual

Problem parts
Inhibitor switch
Control module
Vehicle speed sensor 1
Vehicle speed sensor 2
Select cable
Select lever
FWD switch
Starter motor and harness
Throttle position sensor
Hold switch
Accumulator (“N”—“D”)
Accumulator (2A)
Accumulator (4A)
Accumulator (3R)
ATF temperature sensor
Strainer
Duty solenoid A
Duty solenoid B
Shift solenoid 1
Shift solenoid 2
Shift solenoid 3
Control valve
Detent spring
Manual plate
Transfer clutch
Transfer valve
Transfer pipe
Duty solenoid C
Forward clutch
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Engine brake is not effected when select
lever is in“3”or“2”range.
Engine brake is not effected when select
lever is in“1”range.
Shift characteristics are erroneous.  
No lock-up occurs.
Vehicle cannot be set in“D”range power
mode.
“D”range power mode cannot be released.
Parking brake is not effected.
Shift lever cannot be moved or is hard to
move from“P”range.
Select lever is hard to move. 
Select lever is too light to move (unreason-
able resistance).
ATF spurts out.
Differential oil spurts out.
Differential oil level changes excessively.
Odor is produced from oil supply pipe.
Shock occurs when select lever is moved
from“1”to“2”range.  
Slippage occurs when select lever is moved
from“1”to“2”range.  
Shock occurs when select lever is moved
from“2”to“3”range.
Slippage occurs when select lever is moved
from“2”to“3”range.
Shock occurs when select lever is moved
from“3”to“4”range.   
Slippage occurs when select lever is moved
from“3”to“4”range.   
Shock occurs when select lever is moved
from“3”to“2”range.
Shock occurs when select lever is moved
from“D”to“1”range.
Shock occurs when select lever is moved
from“2”to“1”range.
Shock occurs when accelerator pedal is
released at medium speeds.
Vibration occurs during straight-forward
operation.
Select lever slips out of position during
acceleration or while driving on rough terrain. 
Vibration occurs during turns (tight corner
“braking”phenomenon).    
Front wheel slippage occurs during standing
starts.      
Vehicle is not set in FWD mode. 
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131
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. General Diagnostics Table

11. Diagnostics Chart with Trouble
Code
A: DIAGNOSTIC TROUBLE CODE (DTC) LIST
DTC
No.Abbreviation
(Subaru select monitor)Item Page
P0100 QA Mass air flow sensor circuit malfunction 135
P0101 QA
—R Mass air flow sensor circuit range/performance problem 141
P0105 P
—S Pressure sensor circuit malfunction 144
P0106 P
—R Pressure sensor circuit range/performance problem 151
P0115 TW Engine coolant temperature sensor circuit malfunction 156
P0120 THV Throttle position sensor circuit malfunction 161
P0121 TH
—R Throttle position sensor circuit range/performance problem 167
P0125 TW
—CL Insufficient coolant temperature for closed loop fuel control 169
P0130 FO2
—V Front oxygen sensor circuit malfunction 171
P0133 FO2
—R Front oxygen sensor circuit slow response 177
P0135 FO2H Front oxygen sensor heater circuit malfunction 180
P0136 RO2
—V Rear oxygen sensor circuit malfunction 185
P0139 RO2
—R Rear oxygen sensor circuit slow response 190
P0141 RO2H Rear oxygen sensor heater circuit malfunction 193
P0170 FUEL Fuel trim malfunction 198
P0201 INJ1 Fuel injector circuit malfunction - #1
203 P0202 INJ2 Fuel injector circuit malfunction - #2
P0203 INJ3 Fuel injector circuit malfunction - #3
P0204 INJ4 Fuel injector circuit malfunction - #4
P0301 MIS
—1 Cylinder 1 misfire detected
210 P0302 MIS
—2 Cylinder 2 misfire detected
P0303 MIS
—3 Cylinder 3 misfire detected
P0304 MIS
—4 Cylinder 4 misfire detected
P0325 KNOCK Knock sensor circuit malfunction 217
P0335 CRANK Crankshaft position sensor circuit malfunction 221
P0340 CAM Camshaft position sensor circuit malfunction 225
P0400 EGR Exhaust gas recirculation flow malfunction 229
P0403 EGRSOL Exhaust gas recirculation circuit malfunction 235
P0420 CAT Catalyst system efficiency below threshold 240
P0441 CPC
—F Evaporative emission control system incorrect purge flow 244
P0443 CPC Evaporative emission control system purge control valve circuit malfunction 248
P0500 VSP Vehicle speed sensor malfunction 253
P0505 ISC Idle control system malfunction 256
P0506 ISC
—L Idle control system RPM lower than expected 262
P0507 ISC
—H Idle control system RPM higher than expected 264
P0600—Serial communication link malfunction 266
P0601 RAM Internal control module memory check sum error 268
P0703 BRK Brake switch input malfunction 271
133
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

DTC
No.Abbreviation
(Subaru select monitor)Item Page
P0705 RNG Transmission range sensor circuit malfunction 274
P0710 ATF Transmission fluid temperature sensor circuit malfunction 279
P0720 ATVSP Output speed sensor (vehicle speed sensor 1) circuit malfunction 281
P0725 ATNE Engine speed input circuit malfunction 283
P0731 GR
—1 Gear 1 incorrect ratio
285 P0732 GR
—2 Gear 2 incorrect ratio
P0733 GR
—3 Gear 3 incorrect ratio
P0734 GR
—4 Gear 4 incorrect ratio
P0740 LU
—F Torque converter clutch system malfunction 289
P0743 LU Torque converter clutch system electrical 294
P0748 PL Pressure control solenoid electrical 296
P0753 SFT1 Shift solenoid A electrical 298
P0758 SFT2 Shift solenoid B electrical 300
P0760 OVR
—F Shift solenoid C malfunction 302
P0763 OVR Shift solenoid C electrical 307
P1100 ST
—SW Starter switch circuit malfunction 309
P1101 N
—SW Neutral position switch circuit malfunction [MT vehicles] 311
P1101 N
—SW Neutral position switch circuit malfunction [AT vehicles] 315
P1102 BR Pressure sources switching solenoid valve circuit malfunction 319
P1103 TRQ Engine torque control signal circuit malfunction 325
P1104 TCS TCS signal circuit malfunction 328
P1500 FAN
—1 Radiator fan relay 1 circuit malfunction 331
P1502 FAN
—F Radiator fan function problem 338
P1700 ATTH Throttle position sensor circuit malfunction for automatic transmission 341
P1701 CRS Cruise control set signal circuit malfunction for automatic transmission 343
P1702 ATDIAG Automatic transmission diagnosis input signal circuit malfunction 346
134
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0142
B: DTC P0100
—MASS AIR FLOW SENSOR CIRCUIT
MALFUNCTION (QA)—
OBD0143A
DESCRIPTION:

The MFI system employs a hot film type air flow sensor.
These mass air flow sensors convert the amount of air
taken into the engine into an electric signal by utilizing the
heat transfer phenomenon between the incoming air and a
heating resistor (hot film) located in the air intake.

The features of these flow sensor types are as follows:
1) High-altitude compensation is made automatically.
2) Quick response
3) These are no moving parts.
4) They are compact.
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Poor driving performance
135
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

1.Connect Subaru Select Monitor or the OBD-
II general scan tool, and read data.5.Check harness.
2.Check input signal for ECM. (Using voltage
meter and Subaru Select Monitor.)
3.Check power supply to mass air flow
sensor.
4.Check harness connector between ECM and
mass air flow sensor.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>
WIRING DIAGRAM:

LHD model
OBD0144



136
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0145A
B2M0271
OBD0616
1CONNECT SUBARU SELECT MONITOR OR
THE OBD-II GENERAL SCAN TOOL, AND
READ DATA.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
3) Turn ignition switch to ON and Subaru Select Monitor or
the OBD-II general scan tool switch to ON.
4) Start engine.
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F08 or F47

F08: Voltage input from mass air flow sensor is shown
on display.

F47: Mass air flow is shown on display.

F08: Is sensor output equal to or more
than 0.3 V and equal to or less than
5.0 V?

F47: Is sensor output equal to or more
than 1.3 g/sec and equal to or less
than 250 g/sec?
Probable cause: Poor connect of connectors, circuit and
grounding line.
: Even if MIL lights up, the circuit has returned to a
normal condition at this time. A temporary poor
contact of the connector or harness may be the
cause. Repair harness or connector of the mass
air flow sensor.
HINT:
1Open or short circuit between mass air flow sen-
sor and ECM.

2Poor contact of connectors for mass air flow sen-
sor or ECM.
: Go to next.
: Is the value less than 0.3 V (1.3 g/sec)?
: Go to step 2.
: Go to step 5.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
138
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0689A
2CHECK INPUT SIGNAL FOR ECM. (USING
VOLTAGE METER AND SUBARU SELECT
MONITOR.)
Measure voltage between ECM and body while engine is
idling.
: Connector & terminal
(B84) No. 26—Body/0.3 V, or less
: Go to step 3.
: Go to next.
G2M0527
: Is the voltage more than 0.3 V while shaking
harness and connector of ECM and monitor-
ing the value with Subaru select monitor?
: Repair poor contact in ECM connector.
: Replace ECM with a new one.
B2M0623A
3CHECK POWER SUPPLY TO MASS AIR
FLOW SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from mass air flow sensor.
3) Turn ignition switch to ON.
4) Measure voltage between mass air flow sensor connec-
tor and body.
: Connector & terminal
(B3) No. 1—Body/10 V, or more
: Go to step 4.
: Repair open circuit of harness between main relay
connector and mass air flow sensor connector.
139
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0690A
4CHECK HARNESS CONNECTOR BETWEEN
ECM AND MASS AIR FLOW SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness connector between
ECM and mass air flow sensor.
: Connector & terminal

1(B84) No. 26—(B3) No. 4/10Ω, or less

2(B84) No. 46—(B3) No. 3/10Ω, or less

3(B84) No. 25—(B3) No. 2/10Ω, or less
: Replace mass air flow sensor with a new one.
: Repair poor contact and open circuit of harness
between ECM and mass air flow sensor connec-
tor.
G2M0527
5
CHECK HARNESS.
1) Turn ignition switch to OFF.
2) Disconnect connector from mass air flow sensor.
3) Connect Subaru Select Monitor or OBD-II General
Scan Tool to data link connector.
4) Turn ignition switch to ON.
5) Read data on Subaru select monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F08
: Is the value more than 5 V?
: Repair short circuit of harness between mass air
flow sensor and ECM.
: Go to next.
: Is there poor contact in mass air flow sensor
connector?
: Repair poor contact in mass air flow sensor con-
nector.
: Replace mass air flow sensor.

OBD-II general scan tool
For detailed operation procedures, refer to OBD-II General
Scan Tool Instruction Manual.
140
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0152
C: DTC P0101
—MASS AIR FLOW SENSOR CIRCUIT
RANGE/PERFORMANCE PROBLEM (QA
—R)
—
DESCRIPTION:
Refer to“B: DTC P0100—MASS AIR FLOW SENSOR
CIRCUIT MALFUNCTION—[T11B0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Poor driving performance
141
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

1.Check DTC P0100 on display.
No
Ye s

Inspect DTC P0100 using“11. Diagnostics
Chart with Trouble Code [T1100]”.

In this case, it is unnecessary to inspect DTC
P0101.
Replace mass air flow sensor.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>
WIRING DIAGRAM:

LHD model
OBD0144

142
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code