Subaru Legacy III (2000-2003 year). Manual - part 98

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ENGINE (DIAGNOSTICS)

CHECK LIST FOR INTERVIEW

2. Check List for Interview

A: CHECK

1. CHECK LIST NO. 1

Check the following items when problem has occurred.

NOTE:
Use copies of this page for interviewing customers.

Customer's name

Engine no.

Date of sale

Fuel brand

Date of repair

Odometer reading

km

Vin no.

miles

Weather

❏

 Fine

❏

 Cloudy

❏

 Rainy

❏

 Snowy

❏

 Various/Others:

Outdoor temperature

°

F (

°

C)

❏

 Hot 

❏

 Warm 

❏

 Cool 

❏

 Cold

Place

❏

 Highway 

❏

 Suburbs 

❏

 Inner city 

❏

 Uphill 

❏

 Downhill 

❏

 Rough road 

❏

 Others: 

Engine temperature

❏

 Cold 

❏

 Warming-up 

❏

 After warming-up 

❏

 Any temperature 

❏

 Others: 

Engine speed

rpm

Vehicle speed

MPH

Driving conditions 

❏

 Not affected 

❏

 At starting 

❏

 While idling 

❏

 At racing 

❏

 While accelerating 

❏

 While cruising 

❏

 While decelerating 

❏

 While turning (RH/LH)

Headlight 

❏

 ON/

❏

 OFF

Rear defogger

❏

 ON/

❏

 OFF

Blower

❏

 ON/

❏

 OFF

Radio

❏

 ON/

❏

 OFF

A/C compressor

❏

 ON/

❏

 OFF

CD/Cassette

❏

 ON/

❏

 OFF

Cooling fan 

❏

 ON/

❏

 OFF 

Car phone 

❏

 ON/

❏

 OFF

Front wiper

❏

 ON/

❏

 OFF

CB

❏

 ON/

❏

 OFF

Rear wiper 

❏

 ON/

❏

 OFF

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ENGINE (DIAGNOSTICS)

CHECK LIST FOR INTERVIEW

2. CHECK LIST NO. 2

Check the following items about the vehicle's state when MI turns on.

NOTE:
Use copies of this page for interviewing customers.

a) Other warning lights or indicators turn on. 

❏

 Yes/

❏

 No 

❏

 Low fuel warning light 

❏

 Charge indicator light 

❏

 AT diagnostics indicator light 

❏

 ABS warning light 

❏

 VDC warning light

❏

 Engine oil pressure warning light

b) Fuel level

• Lack of gasoline: 

❏

 Yes/

❏

 No

• Indicator position of fuel gauge: 

c) Intentional connecting or disconnecting of harness connectors or spark plug cords: 

❏

 Yes/

❏

 No

• What:

d) Intentional connecting or disconnecting of hoses: 

❏

 Yes/

❏

 No 

• What:

e) Installing of parts other than genuine parts: 

❏

 Yes/

❏

 No

• What:
• Where: 

f) Occurrence of noise: 

❏

 Yes/

❏

 No

• From where:
• What kind:

g) Occurrence of smell: 

❏

 Yes/

❏

 No

• From where:
• What kind:

h) Intrusion of water into engine compartment or passenger compartment: 

❏

 Yes/

❏

 No

i) Troubles occurred

❏

 Engine does not start. 

❏

 Engine stalls during idling. 

❏

 Engine stalls while driving. 

❏

 Engine speed decreases. 

❏

 Engine speed does not decrease. 

❏

 Rough idling 

❏

 Poor acceleration 

❏

 Back fire 

❏

 After fire 

❏

 No shift 

❏

 Excessive shift shock

EN(H4SO)-6

ENGINE (DIAGNOSTICS)

GENERAL DESCRIPTION

3. General Description

A: CAUTION

1) Airbag system wiring harness is routed near the
engine control module (ECM), main relay and fuel
pump relay.

CAUTION:
• All Airbag system wiring harness and con-
nectors are colored yellow. Do not use electri-
cal test equipment on these circuit.
• Be careful not to damage Airbag system wir-
ing harness when servicing the engine control
module (ECM), transmission control module
(TCM), main relay and fuel pump relay.
2) Never connect the battery in reverse polarity.
• The ECM will be destroyed instantly.
• The fuel injector and other part will be damaged
in just a few minutes more.
3) Do not disconnect the battery terminals while the
engine is running.
• A large counter electromotive force will be gener-
ated in the alternator, and this voltage may damage
electronic parts such as ECM, etc.
4) Before disconnecting the connectors of each
sensor and the ECM, be sure to turn OFF the igni-
tion switch.
5) Poor contact has been identified as a primary
cause of this problem. To measure the voltage and/
or resistance of individual sensors or all electrical
control modules at the harness side connector, use
a tapered pin with a diameter of less than 0.64 mm
(0.025 in). Do not insert the pin more than 5 mm
(0.20 in) into the part.
6) Before removing ECM from the located position,
disconnect two cables on battery.
• Otherwise, the ECM may be damaged.

CAUTION:
When replacing ECM, be careful not to use the
wrong spec. ECM to avoid any damage on fuel
injection system.
7) The connectors to each sensor in the engine
compartment and the harness connectors on the
engine side and body side are all designed to be
waterproof. However, it is still necessary to take
care not to allow water to get into the connectors
when washing the vehicle, or when servicing the
vehicle on a rainy day.

8) Use ECM mounting stud bolts at the body head
grounding point when measuring voltage and resis-
tance inside the passenger compartment.

9) Use engine grounding terminal or engine proper
as the grounding point to the body when measuring
voltage and resistance in the engine compartment.

10) Use TCM mounting stud bolts at the body head
grounding point when measuring voltage and resis-
tance inside the passenger compartment.

11) Every MFI-related part is a precision part. Do
not drop them.

(A) Stud bolt

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ENGINE (DIAGNOSTICS)

GENERAL DESCRIPTION

12) Observe the following cautions when installing
a radio in MFI equipped models.

CAUTION:
• The antenna must be kept as far apart as pos-
sible from the control unit.
(The ECM is located under the steering column,
inside of the instrument panel lower trim panel.)
• The antenna feeder must be placed as far
apart as possible from the ECM and MFI har-
ness.
• Carefully adjust the antenna for correct
matching.
• When mounting a large power type radio, pay
special attention to the three items above men-
tioned.
• Incorrect installation of the radio may affect
the operation of the ECM.
13) Before disconnecting the fuel hose, disconnect
the fuel pump connector and crank the engine for
more than five seconds to release pressure in the
fuel system. If engine starts during this operation,
run it until it stops.
14) Problems in the electronic-controlled automatic
transmission may be caused by failure of the en-
gine, the electronic control system, the transmis-
sion proper, or by a combination of these. These
three causes must be distinguished clearly when
performing diagnostics.
15) Diagnostics should be conducted by rotating
with simple, easy operations and proceeding to
complicated, difficult operations. The most impor-
tant thing in diagnostics is to understand the cus-
tomer's complaint, and distinguish between the
three causes.
16) In AT vehicles, do not continue the stall for
more than five seconds at a time (from closed throt-
tle, fully open throttle to stall engine speed).
17) On ABS vehicle, when performing driving test
in jacked-up or lifted-up position, sometimes the
warning light may be lit, but this is not a malfunction
of the system. The reason for this is the speed dif-
ference between the front and rear wheels. After di-
agnosis of engine control system, perform the ABS
memory clearance procedure of self-diagnosis sys-
tem.

B: INSPECTION

Before performing diagnostics, check the following
items which might affect engine problems:

1. BATTERY

1) Measure battery voltage and specific gravity of
electrolyte.

Standard voltage: 12 V

Specific gravity: Above 1.260

2) Check the condition of the main and other fuses,
and harnesses and connectors. Also check for
proper grounding.

2. ENGINE GROUNDING

Make sure the engine grounding terminal is proper-
ly connected to the engine.

C: NOTE

1. DESCRIPTION

• The on-board diagnostics (OBD) system detects
and indicates a fault in various inputs and outputs
of the complex electronic control. CHECK ENGINE
malfunction indicator lamp (MI) in the combination
meter indicates occurrence 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 compo-
nents and the system malfunction listed in Engine
Section which affects on emissions.
• When the system decides that a malfunction oc-
curs, MI illuminates. At the same time of the MI illu-
mination or blinking, a diagnostic trouble code
(DTC) and a freeze frame engine conditions are
stored into on-board computer.
• The OBD system stores freeze frame engine
condition data (engine load, engine coolant tem-
perature, fuel trim, engine speed and vehicle
speed, etc.) into on-board computer when it detects
a malfunction first.
• If the OBD system detects the various malfunc-
tions including the fault of fuel trim or misfire, the
OBD system first stores freeze frame engine condi-
tions about the fuel trim or misfire.
• When the malfunction does not occur again for
three consecutive driving cycles, MI 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.

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