1996 SUBARU LEGACY coolant temperature

6. READ DATA FUNCTION KEY LIST FOR ENGINE
Function mode Contents Abbreviation Unit of measure
F00 ROM ID number YEAR—
F01 Battery voltage VB V
F02 Vehicle speed signal VSP km/h, MPH
F03 Engine speed signal EREV rpm
F04 Engine coolant temperature signal TW°C,°F
F05 Ignition signal ADVS deg
F06 Mass air flow signal QA g/s, V
F07 Throttle position signal THV %, V
F08 Injector pulse width TIM mS
F09 Idle air control signal ISC %
F10 Load data LOAD %
F11 Front oxygen sensor output signal O2 V
F12 Front oxygen sensor maximum and minimum output signal O2max - min V, V
F13 Rear oxygen sensor output signal RO2 V
F14 Rear oxygen sensor maximum and minimum output signal RO2max - min V, V
F17 Short term fuel trim ALPHA %
F19 Knock sensor signal KNOCK deg
F20 Atmospheric absolute pressure signal BARO. P kPa, mmHg
F21 Intake manifold absolute pressure signal MANI. P kPa, mmHg
F29 A/F correction (short term trim) by rear oxygen sensor PHOS %
F30 Long term fuel trim KBLRC %
F31 Long term whole fuel trim K0 %
F32 Front oxygen sensor heater current FO2H A
F33 Rear oxygen sensor heater current RO2H A
F35 Purge control solenoid valve duty ratio CPCD %
F36Maximum value of cylinder #1 misfire times during 100 rota-
tionsMF1 %
F37Maximum value of cylinder #2 misfire times during 100 rota-
tionsMF2 %
F38Maximum value of cylinder #3 misfire times during 100 rota-
tionsMF3 %
F39Maximum value of cylinder #4 misfire times during 100 rota-
tionsMF4 %
F42Maximum and minimum EGR system pressure value (AT
vehicles only)EGRmax - min kPa
F43 Fuel tank pressure signal TNKP kPa, mmHg
F44 Fuel temperature signal TNKT°C,°F
F45 Fuel level signal FLEVEL V
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——
FA 5 O N)OFF signal——
FB0 Diagnostic trouble code (DTC) INSPECT—
FB1 Diagnostic trouble code (DTC) OBD—
37
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

Function mode Contents Abbreviation Unit of measure
FB2Load data (Freeze frame data) LOADF %
Engine coolant temperature signal (Freeze frame data) TWF °C
Throttle position signal (Freeze frame data) ALPHF %
Long term fuel trim (Freeze frame data) KBLRF %
Intake manifold absolute pressure signal (Freeze frame data) MANIF kPa
Engine speed signal (Freeze frame data) EREVF rpm
Vehicle speed signal (Freeze frame data) VSPF km/h
FB3Mass air flow signal (Freeze frame data) QAF (P0100) V
Pressure signal (Freeze frame data) PSF (P0105) V
Pressure signal (Freeze frame data) PRF (P0106) V
Engine coolant temperature signal (Freeze frame data) TWF (P0115) V
Throttle position signal (Freeze frame data) THVF (P0120) V
EGR control solenoid valve signal (Freeze frame data) EGR (P0403) —*1
Purge control solenoid valve signal (Freeze frame data) CPC (P0443) —*1
Start switch signal (Freeze frame data) STSW (P1100) —*1
Pressure sources switching solenoid valve signal (Freeze
frame data)BR1 (P1102) —*1
Radiator fan relay 1 signal (Freeze frame data) FAN1 (P1500) —*1
FC0 Clear memory — —
FD01 Compulsory fuel pump relay operation check FUEL PUMP —
FD02 Compulsory purge control solenoid valve operation check CPC SOL —
FD03 Compulsory radiator fan relay operation check RAD FAN —
FD04 Compulsory A/C relay operation check A/C RELAY —
FD05 Compulsory EGR control solenoid valve operation check EGR SOL —
FD07 Compulsory pressure control solenoid valve operation check PCV SOL —
FD08 Compulsory vent control solenoid valve operation check VENT SOL —
FD10Compulsory pressure sources switching solenoid valve opera-
tion checkBR SOL —
NOTE:
1) Subaru select monitor is also available for monitoring
information other than that used for check and repair of the
vehicle.
2) F42 (Maximum and minimum EGR system pressure
value) will not read accurately until the EGR flow diagno-
sis terminates.
EGR flow diagnosis terminates when LED No. 2 illuminates
at function mode FA4.
3) *1: “Hi” or “Low” is shown instead of measured value.
4) Because ASV solenoid valve, FICD solenoid valve and
air injection system diagnosis solenoid valve are not
installed, FD06, FD09 and FD11 will be displayed but non-
functional.
38
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

B2M0754
9. FUNCTION MODE: F02
—VEHICLE SPEED SIGNAL (VSP)—

Vehicle speed is indicated in kilometer per hour (km/h)
and mile per hour (MPH) at the same time.
B2M0478
10. FUNCTION MODE: F03
—ENGINE SPEED SIGNAL (EREV)—
B2M0479
11. FUNCTION MODE: F04
—ENGINE COOLANT TEMPERATURE SIGNAL (TW)
—

Engine coolant temperature is indicated in“°C”and“°F”
at the same time.
B2M0480
12. FUNCTION MODE: F05
—IGNITION SIGNAL (ADVS)—
NOTE:
The ignition timing value displayed in mode F05 is a value
computed by ECM and will not always correspond with the
value measured with a timing light.
B2M0481
13. FUNCTION MODE: F06
—MASS AIR FLOW SIGNAL (QA)—

Mass air flow and voltage input from mass air flow sen-
sor are shown on display at the same time.
40
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

47. FB MODE FOR ENGINE
Function mode Abbreviation Contents Contents of display Page
FB0 INSPECT On-board diagnostics (Inspection)Current trouble code indicated by on-board
diagnostics after clear memory.58

FB1 OBD On-board diagnostics (Read data)Current trouble code indicated by on-board
diagnostics.32

FB2LOADF Load data

Freeze frame data

Data stored at the time of trouble
occurrence, is shown on display.34
TWF Engine coolant temperature signal
ALPHF Throttle position signal
KBLRF Long term fuel trim
MANIFIntake manifold absolute pressure
signal
EREVF Engine speed signal
VSPF Vehicle speed signal
FB3QAF (P0100) Mass air flow signal

Freeze frame data

Data stored at the time of trouble
occurrence, is shown on display.35
PSF (P0105) Pressure signal
PRF (P0106) Pressure signal
TWF (P0115) Engine coolant temperature signal
THVF (P0120) Throttle position signal
EGR (P0403) EGR control solenoid valve signal
CPC (P0443) Purge control solenoid valve signal
STSW (P1100) Start switch signal
BR1 (P1102)Pressure sources switching sole-
noid valve signal
FAN1 (P1500) Radiator fan relay 1 signal
48. FC MODE FOR ENGINE
Function mode Abbreviation Contents Contents of display Page
FC0 MEMORY CLR Back-up memory clearFunction of clearing trouble code stored in
memory.57

49. FD MODE FOR ENGINE
Function mode Abbreviation Contents Contents of display Page
FD01 FUEL PUMP
Compulsory valve operation checkFunction of checking operation of fuel
pump relay, purge control solenoid valve,
radiator fan relay, A/C relay, EGR control
solenoid valve, pressure control solenoid
valve, vent control solenoid valve and pres-
sure sources switching solenoid valve.63
FD02 CPC SOL
FD03 RAD FAN
FD04 A/C RELAY
FD05 EGR SOL
FD07 PCV SOL
FD08 VENT SOL
FD10 BR SOL
NOTE:
Because ASV solenoid valve, FICD solenoid valve and air
injection system diagnosis solenoid valve are not installed,
FD06, FD09 and FD11 will be displayed but non-functional.
50
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 ON
(Engine OFF)Engine ON (Idling)
Crankshaft
position
sensorSignal (+) B84 8 07—+7 Sensor output waveform
Signal () B84 29 0 0—
Shield B84 54 0 0—
Camshaft
position
sensorSignal (+) B84 7 07—+7 Sensor output waveform
Signal () B84 28 0 0—
Shield B84 54 0 0—
Mass air
flow sensorSignal B84 5 0—0.3 0.8—1.2—
Shield B84 57 0 0—
GND B84 20 0 0—
Throttle
position
sensorSignal B84 6Fully closed: 0.2—1.0
Fully opened: 4.2—4.7—
Power
supplyB84 21 5 5—
GND B84 20 0 0—
Front
oxygen
sensorSignal B84 23 0 0—0.9—
Shield B84 56 0 0—
Rear
oxygen
sensorSignal B84 24 0 0—0.9—
Shield B84 56 0 0—
Engine coolant
temperature sensorB84 22 1.0—1.4 1.0—1.4 After warm-up
Vehicle speed sensor 2 B84 83 0 or 5 0 or 5“5”and“0”are repeatedly
displayed when vehicle is
driven.
Starter switch B84 86 0 0 Cranking: 8 to 14
A/C switch B84 60ON: 10—13
OFF: 0ON: 13—14
OFF: 0—
Ignition switch B84 85 10—13 13—14—
Neutral position switch
(MT)
B84 82ON: 5.0±0.5
OFF: 0
On MT model; switch is ON
when gear is in neutral position.
Neutral position switch
(AT)ON: 0
OFF: 5.0±0.5
On AT model; switch is ON when
shift is in“N”or“P”position.
Test mode connector B84 84 5 5 When connected: 0
70
2-7ON-BOARD DIAGNOSTICS II SYSTEM
5. Specified Data

9. 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 ignitor, 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 or 2-3b of
the Service Manual.
11 8
2-7ON-BOARD DIAGNOSTICS II SYSTEM
9. General Diagnostics Table

10. 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 125
P0101 QA
—R Mass air flow sensor circuit range/performance problem 132
P0105 P
—S Pressure sensor circuit malfunction 134
P0106 PS
—R Pressure sensor circuit range/performance problem 142
P0115 TW Engine coolant temperature sensor circuit malfunction 147
P0120 THV Throttle position sensor circuit malfunction 151
P0121 TH
—R Throttle position sensor circuit range/performance problem 157
P0125 TW
—CL Insufficient coolant temperature for closed loop fuel control 159
P0130 FO2
—V Front oxygen sensor circuit malfunction 161
P0133 FO2
—R Front oxygen sensor circuit slow response 164
P0135 FO2H Front oxygen sensor heater circuit malfunction 166
P0136 RO2
—V Rear oxygen sensor circuit malfunction 172
P0139 RO2
—R Rear oxygen sensor circuit slow response 177
P0141 RO2H Rear oxygen sensor heater circuit malfunction 179
P0170 FUEL Fuel trim malfunction 185
P0180 TNKT Fuel temperature sensor A circuit malfunction 190
P0181 TNKT
—F Fuel temperature sensor A circuit range/performance problem 195
P0201 INJ1 Fuel injector circuit malfunction - #1
197 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
203 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 211
P0335 CRANK Crankshaft position sensor circuit malfunction 215
P0340 CAM Camshaft position sensor circuit malfunction 218
P0400 EGR Exhaust gas recirculation flow malfunction 221
P0403 EGRSOL Exhaust gas recirculation circuit malfunction 227
P0420 CAT Catalyst system efficiency below threshold 233
P0440 EVAP Evaporative emission control system malfunction 236
P0441 CPC
—F Evaporative emission control system incorrect purge flow 241
P0443 CPC Evaporative emission control system purge control valve circuit malfunction 244
P0446 VCMSOL Evaporative emission control system vent control malfunction 249
P0450 TNKP Evaporative emission control system pressure sensor malfunction 255
P0451 TNKP
—F Evaporative emission control system pressure sensor range/performance problem 264
123
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code

OBD0172
F: DTC P0115
—ENGINE COOLANT TEMPERATURE
SENSOR CIRCUIT MALFUNCTION (TW)—
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Hard to start

Erroneous idling

Poor driving performance
10F1Connect Subaru Select Monitor or the OBD-II
general scan tool, and read data.

10F2Check harness between engine coolant
temperature sensor and ECM connector.
10F3Check harness between engine coolant
temperature sensor and ECM connector.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

WIRING DIAGRAM:
B2M0539

147
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostics Chart with Trouble Code