Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 195

EN(H4DOTC)(diag)-4

Check List for Interview

ENGINE (DIAGNOSTICS)

2. Check List for Interview

A: CHECK

1. CHECK LIST NO. 1

Check the following item when problem has occurred.
NOTE:

Use copies of this page for interviewing customers.

Customer’s name

Engine No.

Date of purchase

Fuel type

Date of repair

Odometer reading

km

V.I.N.

miles

Weather

Fine
Cloudy
Rainy
Snowy
Various/Others:

Ambient air temperature

°C (°F)

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

km/h (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

Audio

ON/

OFF

A/C compressor

ON/

OFF

Rear entertainment system

ON/

OFF

Radiator fan

ON/

OFF

Car phone

ON/

OFF

Front wiper

ON/

OFF

Wireless device

ON/

OFF

Rear wiper

ON/

OFF

EN(H4DOTC)(diag)-5

Check List for Interview

ENGINE (DIAGNOSTICS)

2. CHECK LIST NO. 2

Check the following item about the vehicle’s state when the malfunction indicator light turns on.
NOTE:

Use copies of this page for interviewing customers.

a) Other warning lights or indicators illuminate:

Yes /

No

Fuel level warning light
Charge warning light
Engine coolant temperature warning light
Oil pressure warning light
ATF temperature warning light or SPORT indicator light
Driver’s control center differential indicator light
ABS warning light
VDC warning light
Cruise indicator light
SI-CRUISE warning light
Immobilizer indicator light
STEERING warning light
Electronic parking brake warning light
Glow indicator light
Sedimenter warning light
Others:

b) Fuel level
• Lack of fuel:

Yes /

No

• Indicator position of fuel gauge:
• Experienced running out of fuel:

Yes /

No

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

Yes /

No

• What:
d) Intentional connecting or disconnecting of hoses:

Yes /

No

• What:
e) Installing of other parts except 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
Does not shift.
Excessive shift shock

EN(H4DOTC)(diag)-6

General Description

ENGINE (DIAGNOSTICS)

3. General Description

A: CAUTION

1) Airbag system wiring harness is routed near the

ECM, main relay and fuel pump relay.
CAUTION:

• Do not use electrical test equipment on the

airbag system circuits.

• Be careful not to damage the airbag system

wiring harness when servicing the ECM, TCM,

main relay and fuel pump relay.

2) Never connect the battery in reverse polarity.

Doing so will damage the ECM instantly, and other

parts will also be damaged.

3) Do not disconnect the battery terminals while the

engine is running. A large counter electromotive

force will be generated in the generator, and this

voltage may damage electronic parts such as ECM

etc.

4) When disconnecting the connectors of the elec-

trical components, always be sure to turn the igni-

tion switch to OFF. Perform the Clear Memory

Mode after connecting the connectors. <Ref. to

EN(H4DOTC)(diag)-63, Clear Memory Mode.>

5) When measuring the voltage or resistance of in-

dividual sensor or all electrical control modules,

use a tapered pin with a diameter of less than 0.6

mm (0.024 in). Do not insert the pin 4 mm (0.16 in)

or more into the part.
CAUTION:

When replacing the ECM, be careful not to use

the ECM of wrong specification to avoid any

damage on the fuel injection system.
NOTE:

When replacing the ECM of the models with immo-

bilizer, immobilizer system must be registered. For

detailed procedures, refer to “REGISTRATION

MANUAL FOR IMMOBILIZER”.

6) Take care not to allow water to get into the con-

nectors when servicing or washing the vehicle in

rainy weather. Avoid exposure to water even if the

connectors are waterproof.

7) Use ECM mounting stud bolts for the grounding

point when measuring voltage and resistance in-

side the passenger compartment.

8) Use the engine ground terminal or engine as-

sembly for the grounding point when measuring the

voltage and resistance in engine compartment.

9) All parts related to the engine control system are

precision parts. Do not drop or otherwise apply im-

pact. Do not reuse the parts that are dropped acci-

dentally.

10) Observe the following cautions when installing

a radio in vehicle.
CAUTION:

• The antenna must be kept as far apart as pos-

sible from the ECM. <Ref. to EN(H4DOTC)(di-

ag)-9,

CONTROL

MODULE,

LOCATION,

Electrical Component Location.>

• The antenna feeder must be placed as far

apart as possible from the ECM and engine

control system harness.

• Carefully adjust the antenna for correct

matching.

• When mounting a large power type radio, pay

special attention to the three items mentioned

above.

• Incorrect installation of the radio may affect

the operation of ECM.

(A) Stud bolt

EN-00069

(A)

FU-01170

EN(H4DOTC)(diag)-7

General Description

ENGINE (DIAGNOSTICS)

11) When disconnecting the fuel hose, be sure to

release the fuel pressure beforehand. <Ref. to

FU(STI)-67, RELEASING OF FUEL PRESSURE,

PROCEDURE, Fuel.> <Ref. to FU(w/o STI)-65,

RELEASING OF FUEL PRESSURE, PROCE-

DURE, Fuel.>

12) Warning lights may illuminate when performing

driving test with jacked-up or lifted-up condition, but

this is not a system malfunction. The reason for this

is the rotating speed difference between the front

and rear wheels. After diagnosis of engine control

system, perform the VDC memory clear procedure

of self-diagnosis function. <Ref. to VDC(diag)-27,

Clear Memory Mode.>

B: INSPECTION

Before performing diagnostics, check the following

item which might affect engine problems.

1. BATTERY

1) Measure the battery voltage and specific gravity

of the electrolyte.
Standard voltage: 12 V
Specific gravity: 1.260 or more

2) Check the condition of the main and other fuses,

and harnesses and connectors. Also check for

proper grounding.

2. ENGINE GROUND

Make sure that the engine ground terminal is prop-

erly connected to the engine.

C: NOTE

• The on-board diagnostic (OBD) system detects

and indicates a fault in various inputs and outputs

of the complex electronic control. Malfunction indi-

cator light in the combination meter indicates oc-

currence of a fault or trouble.

• Further, against such a failure of sensors as may

disable the drive, the fail-safe function is provided

to ensure the minimal drivability.

• The OBD system incorporated with the vehicles

within this type of engine complies with OBD-II reg-

ulations. 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, malfunction indicator light illuminates. At the

same time of the malfunction indicator light illumi-

nation or blinking, a DTC and a freeze frame en-

gine 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.

• Freeze frame engine condition data are stored

until the DTCs are cleared. However when such

malfunctions as fuel trim fault and misfire are de-

tected with the freeze frame engine condition data

stored, they are rewritten into those related to the

fuel trim fault and misfire.

• When the malfunction does not occur again for

three consecutive driving cycles*, malfunction indi-

cator light is turned off, but DTC remains at on-

board computer.

*: One driving cycle means the period between the

ignition switch ON and the ignition switch OFF after

driving.

• When performing diagnosis, connect the Subaru

Select Monitor or general scan tool to the vehicle.

FU-01170