Subaru 2006 Legacy, Manual

Page: 1534 / 4302

EN(H4DOTC)(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:
• All the airbag system wiring harnesses and
connectors are colored yellow. Do not use elec-
trical test equipment on these 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.
The ECM will be destroyed instantly.
The fuel injector and other parts will be damaged.
3) Do not disconnect the battery terminals while the
engine is running.
A large counter electromotive force will be generat-
ed 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.
5) Poor contact has been identified as a primary
cause of this problem. Measure the voltage or re-
sistance of individual sensor or all electrical control
modules using 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) Remove the ECM from the located position after
disconnecting two cables on battery.
Otherwise, the ECM may be damaged.
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. Refer to the “IMMOBILIZER TEACHING
OPERATION MANUAL”.
7) Connectors of each sensor in the engine com-
partment and the harness connectors on the en-
gine side and body side are all designed to be
waterproof. Even if the connectors are waterproof,
take care not to allow water to get into them when
washing the vehicle, or when servicing the vehicle
in rainy weather.
8) Use ECM mounting stud bolts at the grounding
point to chassis when measuring voltage and resis-
tance in the passenger compartment.
9) Use the engine ground terminal or engine as-
sembly as the grounding point to chassis when
measuring the voltage and resistance in engine
compartment.
10) Every MFI-related part is a precision part. Do
not drop them.
11) 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 control unit. (The ECM is located un-
der the steering column, inside of 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 mentioned
above.
• Incorrect installation of the radio may affect
the operation of ECM.
12) Before disconnecting the fuel hoses, discon-
nect the fuel pump connector and crank the engine
for more than 5 seconds to release the pressure of
fuel system. If engine starts during this operation,
run it until it stops.
(A) Stud bolt
EN-00069
(A)
FU-01170
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