GENERAL -
How to Use Troubleshooting/Inspection Service Points
00-13
INSPECTION SERVICE POINTS FOR A BLOWN
FUSE
Remove the blown fuse and measure the resistance between
the load side of the blown fuse and the earth. Set the switches
of all circuits which are connected to this fuse to a condition
of continuity. If t he resistance is almost 0 W at this time,
there is a short somewhere between these switches and the
load. If the resistance is not 0 W, there is no short at t he
present time, but a momentary short has probably caused
the fuse to blow.
The main causes of a short circuit are the following.
D Harness being clamped by the vehicle body
D Damage to the outer casing of the harness due to wear
or heat
D Water getting into the connector or circuitry
D Human error (mistakenly shorting a circuit, etc.)
POINTS TO NOTE FOR INTERMITTENT
MALFUNCTIONS
Intermittent malfunctions often occur under certain conditions,
and if these conditions can be ascertained, determining the
cause becomes simple. In order to ascertain the conditions
under which an intermittent malfunction occurs, first ask the
customer for details about the driving conditions, weather
conditions, frequency of occurrence a nd trouble symptoms,
and then try to recreate the trouble symptoms. Next, ascertain
whether the reason why the trouble symptom occurred under
these conditions is du e to vibration, temperature or some
other factor. If vibration is thought to be the cause, carry
out the following checks with the connectors and components
to confirm whether the trouble symptom occurs.
The objects to be checked are connectors and components
which are indicated by inspection procedures or given as
probable causes (which generates diagnosis codes or trouble
symptoms.)
D Gently shake the connector up, down and to the left and
right.
D Gently shake the wiring harness up, down and to the
left and right.
D Gently rock each sensor and relay, etc. by hand.
D Gently shake the wiring harness at suspensions and other
moving parts.
NOTE
If determining the cause is difficult, the flight recorder function
of the MUT-II can also be used.
Fuse
Battery
Load
switch
Load
Short circuit
occurrence
section
To Next Page
Loading...
Need help?
General
