Subaru Legacy IV (2008 year). Manual - part 508

 

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Subaru Legacy IV (2008 year). Manual - part 508

 

 

EN(H6DO)(diag)-5

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 the electrical test equipment on
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.
Failure to do 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) Before disconnecting the connectors of each
sensor and ECM, be sure to turn the ignition switch
to OFF. Perform the Clear Memory Mode after con-
necting the connectors. <Ref. to EN(H6DO)(diag)-
52, 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 wrong spec. ECM 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. To
do so, all ignition keys and ID cards need to be pre-
pared. For detailed operation procedures, refer to
the “PC application help for Subaru Select Moni-
tor”.
6) Take care not to allow water to get into the con-
nector when servicing the vehicle in rainy weather
or when washing the vehicle. Avoid exposure to
water even if the connectors are waterproof.

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

8) Use the engine ground terminal or engine as-
sembly for the grounding point to chassis when
measuring the voltage and resistance in engine
compartment.

9) Every engine control system-related part is a
precision part. Do not drop them.
10) Observe the following cautions when installing
a radio in vehicle.

CAUTION:
• The antenna must be kept as far apart as pos-
sible from control module. (The ECM is located
under the passenger’s seat floor mat.)
• 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.
11) When disconnecting the fuel hose, release the
fuel pressure. <Ref. to FU(H6DO)-43, RELEASING
OF FUEL PRESSURE, PROCEDURE, Fuel.>

(A) Stud bolt

EN-00001

(A)

EN-02473

EN(H6DO)(diag)-6

General Description

ENGINE (DIAGNOSTICS)

12) For the model with ABS, the ABS warning light
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
speed difference between the front and rear
wheels. After diagnosis of engine control system,
perform the ABS memory clear procedure of self-
diagnosis function.

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

Check if the engine ground terminal is properly
connected to 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 or 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.
• When troubleshooting the vehicle which com-
plies with OBD-II regulations, connect the Subaru
Select Monitor or general scan tool to the vehicle.

EN-02473

EN(H6DO)(diag)-7

General Description

ENGINE (DIAGNOSTICS)

D: PREPARATION TOOL

ILLUSTRATION

TOOL NUMBER

DESCRIPTION

REMARKS

1B022XU0

SUBARU SELECT 
MONITOR III KIT

Used for troubleshooting the electrical system.

18252AA000

CRANKSHAFT 
SOCKET

Used for rotating crankshaft.

ST1B022XU0

ST18252AA000

EN(H6DO)(diag)-8

Electrical Component Location

ENGINE (DIAGNOSTICS)

4. Electrical Component Location

A: LOCATION

1. CONTROL MODULE

(1)

Engine control module (ECM)

(3)

Delivery (test) mode connector

(4)

Data link connector

(2)

Malfunction indicator light

 

 

 

 

(1)

(4)

(3)

(2)

EN-05722

(1)

EN-01147

EN-03104

CHECK
ENGINE

(2)

EN-02975

(3)

AT-01877

(4)

 

 

 

 

 

 

 

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