Subaru 2009 IMPREZA Service Manual page 422

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) 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(H4SO)(diag)-
55, 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. Refer to the "PC application help for Subaru
Select Monitor".
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.
General Description
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. (ECM is installed un-
der the passenger's side 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.
EN(H4SO)(diag)-5
ENGINE (DIAGNOSTICS)
(A)
(A) Stud bolt
EN-00001
FU-01090