Precautions: 00-4
• When disconnecting and connecting the ECM
couplers, make sure to turn OFF the ignition switch
(1), or electronic parts may get damaged.
Battery
• Battery connection in reverse polarity is strictly
prohibited. Such a wrong connection will damage the
components of the FI system instantly when reverse
power is applied.
• Removing any battery terminal of a running engine is
strictly prohibited. The moment such removal is made,
damaging counter electromotive force will be applied
to the ECM which may result in serious damage.
• Before measuring voltage at each terminal, check to
make sure that battery voltage is 11 V or higher.
Terminal voltage check with a low battery voltage will
lead to erroneous diagnosis.
• Never connect any tester (voltmeter, ohmmeter, or
whatever) to the ECM when its coupler is
disconnected. Otherwise, damage to ECM may result.
• Never connect an ohmmeter to the ECM with its
coupler connected. If attempted, damage to ECM or
sensors may result.
• Be sure to use a specified voltmeter/ohmmeter.
Otherwise, accurate measurements may not be
obtained and personal injury may result.
Electrical Circuit Inspection Procedures
While there are various methods for electrical circuit
inspection, described here is a general method to check
for open and short circuit using an ohmmeter and a
voltmeter.
Open circuit check
Possible causes for the open circuits are as follows. As
the cause can exist in the connector/coupler or terminal,
they need to be checked carefully.
• Loose connection of connector/coupler
• Poor contact of terminal (due to dirt, corrosion or rust,
poor contact tension, entry of foreign object, etc.)
• Wire harness being open
• Poor terminal-to-wire connection
I705H1000004-03
I310G1000010-01
I310G1000011-01
I310G1000012-01
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