Suzuki GSF650A Service Manual page 9

• 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 electronic unit
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 Procedure
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 circuit 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.
When checking system circuits including an electronic
control unit such as ECM, etc., it is important to perform
careful check, starting with items which are easier to
check.
1) Disconnect the negative (–) cable from the battery.
2) Check each connector/coupler at both ends of the
circuit being checked for loose connection. Also
check for condition of the coupler lock if equipped.
I310G1000011-01
1. Sensor
3) Using a test male terminal, check the female
terminals of the circuit being checked for contact
tension.
Check each terminal visually for poor contact
(possibly caused by dirt, corrosion, rust, entry of
foreign object, etc.). At the same time, check to
make sure that each terminal is fully inserted in the
coupler and locked.
If contact tension is not enough, rectify the contact to
I310G1000012-02
increase tension or replace. The terminals must be
clean and free of any foreign material which could
impede proper terminal contact.
"B": Check contact tension by inserting and removing.
"C": Check each terminal for bend and proper alignment.
"A"
"A"
1
"A": Check for loose connection
"B"
"C"
Precautions: 00-4
ECM
I718H1000002-01
I649G1000027-02