sensor SUBARU LEGACY 1997 Service Repair Manual

B6M0557A
2) Disconnect mass air flow sensor connector.
3) Remove four clips securing air cleaner upper cover.
B6M0558
4) Loosen the clamp screw and separate air cleaner upper
cover from air intake duct.
5) Remove air cleaner element.
B6M0559A
6) Remove #3 spark plug cord by pulling boot, not cord
itself.
B6M0560
7) Remove spark plug with the spark plug socket.
8) Installation is in the reverse order of removal.
Tightening torque (Spark plug):
20.6±2.9 N⋅m (2.10±0.30 kg-m, 15.19±2.14 ft-lb)
27
6-1SERVICE PROCEDURE
3. Spark Plug

B6M0557A
2) Disconnect mass air flow sensor connector.
3) Remove four clips securing air cleaner upper cover.
B6M0558
4) Loosen the clamp screw and separate air cleaner upper
cover from air intake duct.
B6M0565A
5) Remove air cleaner element and air cleaner case.
B6M0566A
6) Remove #1 spark plug cord by pulling boot, not cord
itself.
B6M0567A
7) After connecting
1spark plug socket,
2extension and


3Universal Joint to each other, securely set them over the
spark plug in cylinder head.
8) Cover ABS pipes with rag to prevent damage.


1Spark plug socket 16 mm (5/8 in)


2Extension


3Universal Joint


4Extension


5Ratchet
30
6-1SERVICE PROCEDURE
3. Spark Plug

B6M0555A
3) Remove #2 spark plug cord by pulling boot, not cord
itself.
4) For subsequent procedures, refer to the procedure for
#1 spark plug.
CAUTION:
When removing spark plug, cover the ATF cooling
pipes with a rag to prevent damage.
G6M0095
3. #3 SPARK PLUG
1) Disconnect battery ground cable.
B6M0557A
2) Disconnect mass air flow sensor connector.
3) Remove four clips securing air cleaner upper cover.
B6M0558
4) Loosen the clamp screw and separate air cleaner upper
cover from air intake duct.
B6M0565A
5) Remove air cleaner element and air cleaner case.
32
6-1SERVICE PROCEDURE
3. Spark Plug

14. Vehicle Speed Sensor 2
A: GENERAL PRECAUTIONS
1) Be careful not to drop or bump sensor as this may break
built-in magnet.
2) Drive key is designed to separate from vehicle speed
sensor 2. Be careful not to lose it or forget to install.
3) Vehicle speed sensor 2 is installed in part (which con-
tains bearings, etc., finished to a high degree of accuracy).
Do not allow foreign matter (filings, sand, etc.) to get into
it.
4) When checking output of vehicle speed sensor 2 as a
single unit, ensure test leads are connected to their correct
terminals. Failure to do this may damage internal IC.
5) Discard vehicle speed sensor 2 after removal; replace
with new one.
B: REMOVAL
CAUTION:

Be careful when removing vehicle speed sensor 2
immediately after driving vehicle for a while, as tem-
perature around it is high.

Before removing vehicle speed sensor 2, clean dirt,
etc. from surrounding areas. Take care not to allow
foreign matter to get into mounting hole.
B2M0211
1) Remove collector cover.
2) Disconnect vehicle speed sensor 2 connector.
3) Turn and remove vehicle speed sensor 2.
4) Remove key and packing.
35
6-2SERVICE PROCEDURE
14. Vehicle Speed Sensor 2

C: INSTALLATION
CAUTION:

Ensure sensor mounting hole is clean and free of
foreign matter.

Apply grease to tip end of key to prevent key from
falling off sensor.

Align tip end of key with key groove on end of
speedometer shaft during installation.
1) Hand tighten vehicle speed sensor 2, then tighten it
using suitable tool.
Tightening torque required for sensor to reach bottom of
transmission is as follows:
Tightening torque:
0.39—0.88 N⋅m (4.0—9.0 kg-cm, 3.5—7.8 in-lb)
CAUTION:

When torque must be applied that exceeds 0.88 N⋅m
(9.0 kg-cm, 7.8 in-lb), the key and key groove on end of
speedometer may not be aligned properly. Remove the
key, align it correctly and reassemble.

Sensor threads are secured by Locktite. The reas-
sembly must be completed within 5 minutes before
Locktite dries.
2) Tighten vehicle speed sensor 2 further to specified
torque.
Tightening torque:
5.9±1.5 N⋅m (60±15 kg-cm, 52±13 in-lb)
36
6-2SERVICE PROCEDURE
14. Vehicle Speed Sensor 2

3. Combination Meter
A: DIAGNOSTICS PROCEDURE
If speedometer does not operate, or operates abnormally,
check combination meter circuit (shown in flow chart as
described below).
CAUTION:
Make sure that trouble code of vehicle speed sensor 2
system appears in electrical system on-board diagno-
sis.
Speedometer does not operate, or operates
abnormally.
1. Check power supply for combination meter.
OK
Not OK

Check for disconnection of the combination meter
connector terminal.

Check for open circuit between combination meter
and battery.
,Repair or replace wiring harness.
2. Check ground circuit of combination meter.
OK
Not OK
Repair or replace wiring harness.
3. Check harness connector between
combination meter and vehicle speed sensor
2.
OK
Not OK
Repair or replace wiring harness.
4. Check vehicle speed sensor 2.
OK
Not OK
Replace vehicle speed sensor 2.
Failure of the speedometer.





74
6-2DIAGNOSTICS
3. Combination Meter

B6M0530A
1. CHECK POWER SUPPLY FOR COMBINATION
METER.
1) Remove combination meter.
2) Turn ignition switch to ON.
3) Measure voltage at combination meter connector termi-
nal.
Connector & terminal / Specified voltage:
(i14) No. 11—Body / 10 V, or more
B6M0252B
2. CHECK GROUND CIRCUIT OF COMBINATION
METER.
1) Turn ignition switch to OFF.
2) Measure resistance of harness connector between
combination meter and body.
Connector & terminal / Specified voltage:
(i12) No. 1—Body / 10Ω, max.
B6M0294B
3. CHECK HARNESS CONNECTOR BETWEEN
COMBINATION METER AND VEHICLE SPEED
SENSOR 2.
1) Disconnect connector from vehicle speed sensor 2.
2) Measure resistance of harness connector between
vehicle speed sensor 2 and combination meter.
Connector & terminal / Specified resistance:
(B17) No. 1—(i11)No.2/10Ω, max.
(B17) No. 2—(i11)No.3/10Ω, max.
4. CHECK VEHICLE SPEED SENSOR 2.
NOTE:

If resistance between terminals of vehicle speed sensor
2 is out of specification, the sensor may have a failure.

If resistance is OK and voltage between terminals of
vehicle speed sensor 2 is out of specification, mechanical
trouble may be present between vehicle speed sensor 2
and speedometer shaft in transmission.
75
6-2DIAGNOSTICS
3. Combination Meter

B3M0289
1) Disconnect connector from vehicle speed sensor 2.
2) Measure resistance between terminals of vehicle speed
sensor 2.
Terminals / Specified resistance:
No. 1—No. 2 / 350—450Ω
B3M0256
WARNING:
Be careful not to be caught up by the running wheels.
3) Set the vehicle on free roller, or lift-up the vehicle and
support with safety stands.
4) Drive the vehicle at speed greater than 20 km/h (12
MPH).
5) Measure voltage between terminals of vehicle speed
sensor 2.
Terminals / Specified voltage:
No. 1—No.2/5V,min. (AC range)
B3M0257

Using an oscilloscope:
(1) Turn ignition switch to OFF.
(2) Set oscilloscope to vehicle speed sensor 2.
(3) Drive the vehicle at speed greater than 20 km/h (12
MPH).
(4) Measure signal voltage.
Specified voltage (V): 5 V, min.
B3M0254A
76
6-2DIAGNOSTICS
3. Combination Meter

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
consecutive driving cycles, MIL is turned off, but DTC
remains at on-board computer.

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 (AT vehicles only)

23EGR control solenoid valve (AT vehicles only)

24Radiator fan
25Radiator fan relay

26Pressure sources switching solenoid valve

27Knock sensor

28Back-pressure transducer (AT vehicles only)

29Front oxygen sensor

30Rear oxygen sensor (2200 cc Federal spec. vehicles)

31Pressure sensor

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 (For Subaru select monitor)

43Data link connector (For Subaru select monitor and OBD-II
general scan tool)

44Two way valve

45Rear oxygen sensor (2200 cc California spec. vehicles)

46Filter
5
2-7ON-BOARD DIAGNOSTICS II SYSTEM
1. General