Coolant Temp sensor SUBARU LEGACY 1995 Service Repair Manual

3. Engine Coolant Pipe
G2M0203

1Engine coolant temperature sensor


2Engine coolant temperature gauge


3Engine coolant pipe


4O-ring


5By-pass hose
Tightening torque: N⋅m (kg-m, ft-lb)
T: 6.4±0.5 (0.65±0.05, 4.7±0.4)
5
2-5COMPONENT PARTS
3. Engine Coolant Pipe

1. Engine Cooling System
Trouble Possible cause Corrective action
Over-heatinga. Insufficient engine coolantReplenish engine coolant, inspect for leakage, and
repair.
b. Loose timing belt Repair or replace timing belt tensioner.
c. Oil on drive belt Replace.
d. Malfunction of thermostat Replace.
e. Malfunction of engine coolant pump Replace.
f. Clogged engine coolant passage Clean.
g. Improper ignition timingInspect and repair ignition control system.

h. Clogged or leaking radiator Clean or repair, or replace.
i. Improper engine oil in engine coolant Replace engine coolant.
j. Air/fuel mixture ratio too leanInspect and repair fuel injection system.

k. Excessive back pressure in exhaust system Clean or replace.
l. Insufficient clearance between piston and cylinder Adjust or replace.
m. Slipping clutch Repair or replace.
n. Dragging brake Adjust.
o. Improper transmission oil Replace.
p. Defective thermostat Replace.
q. Malfunction of electric fanInspect radiator fan relay, engine coolant temperature
sensor or radiator motor and replace there.
Over-coolinga. Atmospheric temperature extremely low Partly cover radiator front area.
b. Defective thermostat Replace.
Engine coolant
leaks.a. Loosened or damaged connecting units on hoses Repair or replace.
b. Leakage from engine coolant pump Replace.
c. Leakage from engine coolant pipe Repair or replace.
d. Leakage around cylinder head gasket Retighten cylinder head bolts or replace gasket.
e. Damaged or cracked cylinder head and crankcase Repair or replace.
f. Damaged or cracked thermostat case Repair or replace.
g. Leakage from radiator Repair or replace.
Noisea. Defective drive belt Replace.
b. Defective radiator fan Replace.
c. Defective engine coolant pump bearing Replace engine coolant pump.
d. Defective engine coolant pump mechanical seal Replace engine coolant pump.
19
2-5DIAGNOSTICS
1. Engine Cooling System

B2M0342
12) Disconnect brake booster hose.
B2M0343
13) Remove EGR pipe.
G2M0370
14) Disconnect canister hose from pipe.
B2M0019
15) Disconnect engine harness connectors from bulkhead
harness connectors.
B2M0345A
16) Disconnect connectors from engine coolant tempera-
ture sensor

1and thermometer
2.
10
2-7SERVICE PROCEDURE
4. Intake Manifold

G2M0091
3) Connect connector to oil pressure switch.
G2M0408
4) Connect connector to crankshaft position sensor.
G2M0416
5) Connect connector to camshaft position sensor.
B2M0346
6) Connect connector to knock sensor.
B2M0345A
7) Connect connectors to engine coolant temperature sen-
sor

1and thermometer
2.
14
2-7SERVICE PROCEDURE
4. Intake Manifold

G2M0280
16) Connect accelerator cable
1.
17) Connect cruise control cable

2. (With cruise control
model)
B2M0154
18) Install air cleaner element, air cleaner upper cover and
air intake duct.
19) Connect connector to mass air flow sensor.
B2M0154
5. Engine Coolant Temperature Sensor
A: REMOVAL AND INSTALLATION
1) Remove air intake duct.
G2M0407
2) Disconnect connector from engine coolant temperature
sensor.
3) Remove engine coolant temperature sensor.
G2M0407
4) Installation is in the reverse order of removal.
Tightening torque:
25±3 N⋅m (2.5±0.3 kg-m, 18.1±2.2 ft-lb)
17
2-7SERVICE PROCEDURE
4. Intake Manifold - 5. Engine Coolant Temperature Sensor

G2M0280
16) Connect accelerator cable
1.
17) Connect cruise control cable

2. (With cruise control
model)
B2M0154
18) Install air cleaner element, air cleaner upper cover and
air intake duct.
19) Connect connector to mass air flow sensor.
B2M0154
5. Engine Coolant Temperature Sensor
A: REMOVAL AND INSTALLATION
1) Remove air intake duct.
G2M0407
2) Disconnect connector from engine coolant temperature
sensor.
3) Remove engine coolant temperature sensor.
G2M0407
4) Installation is in the reverse order of removal.
Tightening torque:
25±3 N⋅m (2.5±0.3 kg-m, 18.1±2.2 ft-lb)
17
2-7SERVICE PROCEDURE
4. Intake Manifold - 5. Engine Coolant Temperature Sensor

1. General
1. GENERAL DESCRIPTION

The on-board diagnostics (OBD) system detects and
indicates a fault in various inputs and outputs of the com-
plex electronic control. CHECK ENGINE malfunction indi-
cator lamp (MIL) in the combination meter indicates occur-
rence of a fault or trouble.

Further, against such a failure or sensors as may disable
the drive, the fail-safe function is provided to ensure the
minimal driveability.

The OBD system incorporated with the vehicles within
this engine family complies with Section 1968.1, California
Code of Regulations (OBD-II regulation). The OBD system
monitors the components and the system malfunction
listed in Engine Section which affects on emissions.

When the system decides that a malfunction occurs, MIL
illuminates. At the same time of the MIL illumination or
blinking, a diagnostic trouble code (DTC) and a freeze
frame engine conditions are stored into on-board com-
puter.

The OBD system stores freeze frame engine condition
data (engine load, engine coolant temperature, fuel trim,
engine speed and vehicle speed, etc.) into on-board com-
puter when it detects a malfunction first.

If the OBD system detects the various malfunctions
including the fault of fuel trim or misfire, the OBD system
first stores freeze frame engine conditions about the fuel
trim or misfire.

When the malfunction does not occur again for three
trips, MIL is turned off, but DTC remains at on-board com-
puter.

The OBD-II system is capable of communication with a
general scan tool (OBD-II general scan tool) formed by ISO
9141 CARB.

The OBD-II diagnostics procedure is different from the
usual diagnostics procedure. When troubleshooting OBD-II
vehicles, connect Subaru select monitor or the OBD-II gen-
eral scan tool to the vehicle.
A: ENGINE
1. ENGINE AND EMISSION CONTROL SYSTEM

The Multipoint Fuel Injection (MFI) system is a system
that supplies the optimum air-fuel mixture to the engine for
all the various operating conditions through the use of the
latest electronic technology.
With this system fuel, which is pressurized at a constant
pressure, is injected into the intake air passage of the cyl-
inder head. The injection quantity of fuel is controlled by an
intermittent injection system where the electro-magnetic
injection valve (fuel injector) opens only for a short period
of time, depending on the quantity of air required for one
cycle of operation. In actual operation, the injection quan-
2
2-7ON-BOARD DIAGNOSTICS II SYSTEM
1. General

1Engine control module (ECM)

2Ignition coil

3Ignitor

4Crankshaft position sensor

5Camshaft position sensor

6Throttle position sensor

7Fuel injectors

8Pressure regulator

9Engine coolant temperature sensor

10Mass air flow sensor

11Idle air control solenoid valve

12Purge control solenoid valve

13Fuel pump

14PCV valve

15Air cleaner

16Canister

17Main relay

18Fuel pump relay

19Fuel filter

20Front catalytic converter

21Rear catalytic converter

22EGR valve
23EGR control solenoid valve

24Radiator fan

25Radiator fan relay

26Pressure sources switching solenoid valve (AT vehicles only)

27Knock sensor

28Back-pressure transducer (AT vehicles only)

29Front oxygen sensor

30Rear oxygen sensor

31Pressure sensor (AT vehicles only)

32A/C compressor

33Inhibitor switch

34CHECK ENGINE malfunction indicator lamp (MIL)

35Tachometer

36A/C relay

37A/C control module

38Ignition switch

39Transmission control module (TCM) (AT vehicles only)

40ABS/TCS control module (TCS equipped models)

41Vehicle speed sensor

42Data link connector (Subaru select monitor)

43Data link connector (OBD-II general scan tool)

44Two way valve
5
2-7ON-BOARD DIAGNOSTICS II SYSTEM
1. General

3. SENSOR
OBD0009A
1Pressure sensor (AT vehicles only)

2Mass air flow sensor

3Engine coolant temperature sensor

4Throttle position sensor
5Knock sensor

6Camshaft position sensor

7Crankshaft position sensor
OBD0010AOBD0011A
10
2-7ON-BOARD DIAGNOSTICS II SYSTEM
2. Electrical Components Location

3. READ DATA LIST

MODE $01
—Current powertrain diagnostic data—
Refers to data denoting the current operating condition of
analog input/output, digital input/output and/or the power-
train system.
A list of the support data and PID (Parameter Identification)
codes are shown in the following table.
PID DataUnit of measure
01 Number of emission-related powertrain trouble codes and MIL status ON/OFF
03 Fuel system control status—
04 Calculated engine load value%
05 Engine coolant temperature°C
06 Short term fuel trim%
07 Long term fuel trim%
0B Intake manifold absolute pressurekPa
0C Engine revolutionrpm
0D Vehicle speedkm/h
0E Ignition timing advance°
10 Air flow rate from mass air flow sensor g/sec
11 Throttle valve opening angle%
13 Check whether oxygen sensor is installed.—
14 Oxygen sensor output voltage and short term fuel trim associated with oxygen sensor—bank 1 V and %
15 Oxygen sensor output voltage and short term fuel trim associated with oxygen sensor—bank 2 V and %
1C On-board diagnosis system—
NOTE:
Refer to OBD-II general scan tool manufacturer’s instruc-
tion manual to access generic OBD-II PIDs (MODE $01).
29
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System