TGB EST 1000, Service Manual

Page: 42 / 269

4-2. FUEL INJECTION SYSTEM
4-2-4
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Never connect an ohmmeter to the ECU with its coupler connected. If attempted, damage to
the ECU 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
•
Disconnect the negative cable from the battery.
•
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.
•
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 increase tension or replace.
The terminals must be clean and free of any foreign
material, which could impede proper terminal
contact.
•
Using continuity inspect or voltage check
procedure as described below, inspect the wire
harness terminals for open circuit and poor
connection. Locate abnormality, if any.
1. Check for loose connection
1. Looseness of crimping
2. Open
3. Thin wire (a few strands left)