GENERAL INFORMATION 0A-15
Electrical Circuit Inspection Procedure
While there are various electrical circuit inspection methods,
described here is a general method to check its open and short
circuit by using an ohmmeter and a voltmeter.
Open circuit check
Possible causes for the open circuit are as follows. As the cause
is in the connector or terminal in many cases, they need to be
checked particularly carefully.
• Loose connection of connector
• Poor contact of terminal (due to dirt, corrosion or rust on it,
poor contact tension, entry of foreign object etc.)
• Wire harness being open
When checking system circuits including an electronic control unit
such as ECM, TCM, ABS control module, etc., it is important to
perform careful check, starting with items which are easier to
check.
1) Disconnect negative (–) cable from battery
2) Check each connector at both ends of the circuit being
checked for loose connection. Also check lock condition of
connector if equipped with connector lock.
3) Using a test male terminal, check both terminals of the circuit
being checked for contact tension of its female terminal.
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
locked in the connector fully.
4) Using continuity check or voltage check the following proce-
dure, check the wire harness for open circuit and poor con-
nection with its terminals. Locate abnormality, if any.
1. Check contact tension by inserting and removing just for once.
1. Looseness of crimping
2. Open
3. Thin wire (single strand of wire)
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