1997 SUBARU LEGACY engine coolant

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 53 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
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
5. Specified Data

9. General Diagnostic Table
A: GENERAL DIAGNOSTICS TABLE WITH
NONCONFORMITY SYMPTOM FOR ENGINE
NOTE:
Malfunction of parts other than those listed is also possible.

Symptom Problem parts
1. Engine stalls during idling.1) Idle air control solenoid valve
2) Mass air flow sensor
3) Ignition parts (*1)
4) Engine coolant temperature sensor (*2)
5) Crankshaft position sensor (*3)
6) Camshaft position sensor (*3)
7) EGR valve
8) Fuel injection parts (*4)
2. Rough idling1) Idle air control solenoid valve
2) Mass air flow sensor
3) Engine coolant temperature sensor (*2)
4) Ignition parts (*1)
5) Air intake system (*5)
6) Fuel injection parts (*4)
7) Throttle position sensor
8) Crankshaft position sensor (*3)
9) Camshaft position sensor (*3)
10) EGR valve
11) Oxygen sensor
12) Fuel pump and fuel pump relay
3. Engine does not return to idle.1) Idle air control solenoid valve
2) Engine coolant temperature sensor
3) Accelerator cable (*6)
4) Throttle position sensor
5) Mass air flow sensor
4. Poor acceleration1) Mass air flow sensor
2) Throttle position sensor
3) Fuel injection parts (*4)
4) Fuel pump and fuel pump relay
5) Engine coolant temperature sensor (*2)
6) Crankshaft position sensor (*3)
7) Camshaft position sensor (*3)
8) A/C switch and A/C cut relay
9) Engine torque control signal circuit
10) Ignition parts (*1)
5. Engine stalls or engine sags or hesitates at
acceleration.1) Mass air flow sensor
2) Engine coolant temperature sensor (*2)
3) Crankshaft position sensor (*3)
4) Camshaft position sensor (*3)
5) Purge control solenoid valve
6) EGR valve
7) Fuel injection parts (*4)
8) Throttle position sensor
9) Fuel pump and fuel pump relay
6. Surge1) Mass air flow sensor
2) Engine coolant temperature sensor (*2)
3) Crankshaft position sensor (*3)
4) Camshaft position sensor (*3)
5) EGR valve
6) Fuel injection parts (*4)
7) Throttle position sensor
8) Fuel pump and fuel pump relay
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
9. General Diagnostic Table

Symptom Problem parts
7. Spark knock1) Mass air flow sensor
2) Engine coolant temperature sensor
3) Knock sensor
4) Fuel injection parts (*4)
5) Fuel pump and fuel pump relay
8. After burning in exhaust system1) Mass air flow sensor
2) Engine coolant temperature sensor (*2)
3) Fuel injection parts (*4)
4) Fuel pump and fuel pump relay
*1: Check ignitor, ignition coil and spark plug.
*2: Indicate the symptom occurring only in cold temperatures.
*3: Ensure the secure installation.
*4: Check fuel injector, fuel pressure regulator and fuel filter.
*5: Inspect air leak in air intake system.
*6: Adjust accelerator cable.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
9. General Diagnostic Table

10. Diagnostic Chart with Trouble Code
for LHD Vehicles
A: DIAGNOSTIC TROUBLE CODE (DTC) LIST
DTC
No.Abbreviation
(Subaru Select Monitor)Item Page
P0101 QA
—RLOW Mass air flow sensor circuit range/performance problem (low input) 132
P0102 QA
—LOW Mass air flow sensor circuit low input 134
P0103 QA
—HI Mass air flow sensor circuit high input 138
P0106 PS
—R2 Pressure sensor circuit range/performance problem 141
P0107 P
—SLOW Pressure sensor circuit low input 145
P0108 P
—SHI Pressure sensor circuit high input 149
P0116 TW
—LOW Engine coolant temperature sensor circuit low input 154
P0117 TW
—HI Engine coolant temperature sensor circuit high input 157
P0121 TH
—RHI Throttle position sensor circuit range/performance problem (high input) 160
P0122 THV
—LOW Throttle position sensor circuit low input 162
P0123 THV
—HI Throttle position sensor circuit high input 167
P0125 TW
—CL Insufficient coolant temperature for closed loop fuel control 170
P0130 FO2
—V Front oxygen sensor circuit malfunction 172
P0133 FO2
—R Front oxygen sensor circuit slow response 175
P0135 FO2H Front oxygen sensor heater circuit malfunction 177
P0136 RO2
—V Rear oxygen sensor circuit malfunction 181
P0139 RO2
—R Rear oxygen sensor circuit slow response 184
P0141 RO2H Rear oxygen sensor heater circuit malfunction 186
P0170 FUEL Fuel trim malfunction 190
P0181 TNKT
—F Fuel temperature sensor A circuit range/performance problem 195
P0182 TNKT
—LOW Fuel temperature sensor A circuit low input 197
P0183 TNKT
—HI Fuel temperature sensor A circuit high input 200
P0261 INJ1 Fuel injector circuit low input - #1 203
P0262 INJ1
—HI Fuel injector circuit high input - #1 207
P0264 INJ2 Fuel injector circuit low input - #2 203
P0265 INJ2
—HI Fuel injector circuit high input - #2 207
P0267 INJ3 Fuel injector circuit low input - #3 203
P0268 INJ3
—HI Fuel injector circuit high input - #3 207
P0270 INJ4 Fuel injector circuit low input - #4 203
P0271 INJ4
—HI Fuel injector circuit high input - #4 207
P0301 MIS
—1 Cylinder 1 misfire detected 211
P0302 MIS
—2 Cylinder 2 misfire detected 211
P0303 MIS
—3 Cylinder 3 misfire detected 211
P0304 MIS
—4 Cylinder 4 misfire detected 211
P0325 KNOCK Knock sensor circuit malfunction 219
P0335 CRANK Crankshaft position sensor circuit malfunction 222
P0336 CRANK
—R Crankshaft position sensor circuit range/performance problem 225
P0340 CAM Camshaft position sensor circuit malfunction 227
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M1067
H: DTC P0116
—ENGINE COOLANT TEMPERATURE
SENSOR CIRCUIT LOW INPUT—
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Hard to start

Erroneous idling

Poor driving performance
WIRING DIAGRAM:
B2M0539
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

154
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0145A
10H1CONNECT 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.
B2M0479
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F04

F04: Water temperature is indicated in“°C”and“°F”.
: Is the value greater than 150°Cor300°Fin
function mode F04?
: Go to step10H2.
: Repair poor contact.
NOTE:
In this case, repair the following:

Poor contact in engine coolant temperature sensor

Poor contact in ECM

Poor contact in coupling connector (B21)

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
OBD0618A
10H2CHECK HARNESS BETWEEN ENGINE
COOLANT TEMPERATURE SENSOR AND
ECM CONNECTOR.
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.
OBD0145A
4) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
5) Turn ignition switch and Subaru Select Monitor or
OBD-II general scan tool switch to ON.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M0479
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: F04

F04: Water temperature is indicated in“°C”and“°F”.
: Is the value less than40°Cor40°Fin
function mode F04?
: Replace engine coolant temperature sensor.
: Repair ground short circuit in harness between
engine coolant temperature sensor and ECM con-
nector.

OBD-II general scan tool
For detailed operation procedures, refer to the OBD-II Gen-
eral Scan Tool Instruction Manual.
156
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M1068
I: DTC P0117
—ENGINE COOLANT TEMPERATURE
SENSOR CIRCUIT HIGH INPUT—
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Hard to start

Erroneous idling

Poor driving performance
WIRING DIAGRAM:
B2M0539
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES.

157
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles