Coolant SUBARU LEGACY 1995 Service Manual PDF

Function mode Contents Abbreviation Unit of measure
F50 Load data (Freeze frame data) LOADF %
F51 Engine coolant temperature signal (Freeze frame data) TWF °C
F52 Short term fuel trim (Freeze frame data) ALPHF %
F53 Long term fuel trim (Freeze frame data) KBLRF %
F54Intake manifold absolute pressure signal (Freeze frame
data) MANIF kPa
F55 Engine speed signal (Freeze frame data) EREVF rpm
F56 Vehicle speed signal (Freeze frame data) VSPF km/h
FA 0 O N)OFF signal — —
FA 1 O N)OFF signal — —
FA 2 O N)OFF signal — —
FA 3 O N)OFF signal — —
FA 4 O N)OFF signal — —
FB0 Diagnostic trouble code (DTC) INSPECT —
FB1 Diagnostic trouble code (DTC) OBD —
FC0 Clear memory — —
NOTE:
1) Subaru select monitor is also available for monitoring
information other than that used for check and repair of the
vehicle.
2) The maximum values shown for F33, F34, F35 and F36
do not indicate the actual cylinder misfire rate.
36
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

G2M0523

FUNCTION MODE: F02 AND F03
—VEHICLE SPEED SIGNAL (VSP)—

F02: Vehicle speed is indicated in mile per hour (MPH).

F03: Vehicle speed is indicated in kilometer per hour
(km/h).
G2M0524

FUNCTION MODE: F04
—ENGINE SPEED SIGNAL (EREV)—
OBD0176

FUNCTION MODE: F05 AND F06
—ENGINE COOLANT TEMPERATURE
SIGNAL (TW)—

F05: Engine coolant temperature is indicated in“°F”.

F06: Engine coolant temperature is indicated in“°C”.
G2M0654

FUNCTION MODE: F07
—IGNITION SIGNAL (ADVS)—
NOTE:
The ignition timing value displayed in mode F07 is a value
computed by ECM and will not always correspond with the
value measured with a timing light.
B2M0271

FUNCTION MODE: F08
—MASS AIR FLOW SIGNAL (QA)—
38
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

OBD0642

FUNCTION MODE: F50
—LOAD DATA [FREEZE FRAME DATA)
(LOAD
—F)—
OBD0643

FUNCTION MODE: F51
—ENGINE COOLANT TEMPERATURE
SIGNAL [FREEZE FRAME DATA] (TW
—F)—
OBD0644

FUNCTION MODE: F52
—THROTTLE POSITION SIGNAL [FREEZE
FRAME DATA] (ALPH
—F)—
OBD0645

FUNCTION MODE: F53
—LONG TERM FUEL TRIM CONTROL COEFFICIENT> [FREEZE FRAME
DATA] (KBLR
—F)—
OBD0646

FUNCTION MODE: F54
—INTAKE MANIFOLD ABSOLUTE
PRESSURE SIGNAL
[FREEZE FRAME DATA] (MANI
—F)—
45
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

5. Specified Data
1. ENGINE CONTROL MODULE (ECM) I/O SIGNAL
OBD0092A
ContentConnector
No.Terminal
No.Signal (V)
Note Ignition SW
Engine ON (Idling)
ON (Engine OFF)
Crankshaft
position
sensorSignal (+) B84 8 0 ±7 Sensor output waveform
Signal () B84 7 0 0—
Shield B84 52 0 0—
Camshaft
position
sensorSignal (+) B84 6 0 ±7 Sensor output waveform
Signal () B84 5 0 0—
Shield B84 52 0 0—
Mass air
flow
sensorSignal B84 26 0—0.3 0.8—1.2—
Shield B84 54 0 0—
GND B84 25 0 0—
Throttle
position
sensorSignal B84 24Fully closed: 0.2—1.0
Fully opened: 4.2—4.7—
Power
supplyB84 22 5 5—
GND B84 25 0 0—
Front
oxygen
sensorSignal B84 28 0 0)0.9—
Shield B84 56 0 0—
Rear
oxygen
sensorSignal B84 27 0 0)0.9—
Shield B84 56 0 0—
Engine coolant
temperature sensorB84 29 1.0—1.4 1.0—1.4 After warm-up
Vehicle speed sensor
2B84 57 0or5 0or5“5”and“0”are repeatedly
displayed when vehicle is
driven.
67
2-7ON-BOARD DIAGNOSTICS II SYSTEM
5. Specified Data

10. General Diagnostics Table
1. FOR ENGINE
12345678910111213
Problem parts
Mass air flow sensor
Engine coolant temperature sensor (*1)
Throttle position sensor
Crankshaft position sensor & Camshaft position sensor (*2)
Idle air control solenoid valve
Knock sensor
Purge control solenoid valve
EGR valve
Fuel injection parts (*3)
Ignition parts (*4)
Fuel pump and relay
A/C switch and A/C cut relay
Engine torque control signal circuitSymptom
1 Engine stalls during idling.   
2 Rough idling    
3 Engine does not return to idle.
4 Poor acceleration   
5Engine stalls or engine sags or hesi-
tates at acceleration.    
6 Surge   
7 Spark knock
8 After burning in exhaust system  
*1: The mark,, indicates the symptom occurring only in cold temperatures.
*2: For items with the mark,, ensure the secure installation of crankshaft position sensor and camshaft position sensor. Replacement is
not necessary.
*3: Check fuel injector, fuel pressure regulator and fuel filter.
*4: Check igniter, ignition coil and spark plug.
NOTE:
Malfunction of parts other than the above is also possible. Refer to 1. Engine Trouble in General [K100] in Repair Section 2-3 of the Ser-
vice Manual.
128
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

OBD0172
F: DTC P0115
—ENGINE COOLANT TEMPERATURE
SENSOR CIRCUIT MALFUNCTION (TW)—
OBD0173A
DESCRIPTION:
The engine coolant temperature sensor is located on the
engine coolant pipe which is made of aluminum alloy. Its
thermistor changes resistance with respect to temperature.
A engine coolant temperature signal converted into resis-
tance is transmitted to the ECM to control the amount of
fuel injection, ignition timing, purge control solenoid valve,
etc.
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Hard to start

Erroneous idling

Poor driving performance
156
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0145A
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
OBD-II general scan tool switch to ON.
4) Start engine.
OBD0176
OBD0177
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F05 or F06

F05: Water temperature is indicated in“°F”.

F06: Water temperature is indicated in“°C”.
:
Is the value greater than 300°F with func-
tion mode F05?

Is the value greater than 150°C with func-
tion mode F06?
: Go to step 2.
: Go to next.
:
Is the value less than 40°F with function
mode F05?

Is the value less than 40°C with function
mode F06?
: Go to step 3.
: Repair poor contact in connectors or harness.

Engine coolant temperature sensor connector

ECM connector

Coupling connector (B21)

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
OBD0618A
2
CHECK HARNESS.
1) Turn ignition switch to OFF.
2) Remove idle air control solenoid valve by-pass air hose.
3) Disconnect connector from engine coolant temperature
sensor.
158
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0145A
4) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
OBD0176
OBD0177
5) Turn ignition switch and Subaru Select Monitor or
OBD-II general scan tool switch to ON.
6) Read data on Subaru Select Monitor or the OBD-II gen-
eral scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F05 or F06

F05: Water temperature is indicated in“°F”.

F06: Water temperature is indicated in“°C”.
:
Is the value less than40°F with function
mode F05?

Is the value less than40°C with function
mode F06?
: Replace engine coolant temperature sensor.
: Repair short circuit of harness between engine
coolant temperature sensor connector and ECM
connector.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
159
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0618A
3
CHECK HARNESS.
1) Turn ignition switch to OFF.
2) Remove idle air control solenoid valve by-pass air hose.
3) Disconnect connector from engine coolant temperature
sensor.
4) Turn ignition switch to ON.
OBD0696A
5) Measure voltage between engine coolant temperature
sensor and body.
: Connector & terminal
(E8) No. 1—Body/4 V, or more
: Repair open circuit of harness or poor contact in
ECM and engine coolant temperature sensor con-
nector.
: Go to the next step.
6) Turn ignition switch to OFF.
OBD0697A
7) Measure resistance of harness between engine coolant
temperature sensor connector and body.
: Connector & terminal
(E8) No. 2—Body/10Ω, or less
: Repair open circuit of harness or poor contact in
ECM and engine coolant temperature sensor con-
nector.
: Replace engine coolant temperature sensor.
160
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code