Basic Automotive Diagnostic Testing - Urrea UD226 Manual De Usuario Y Garantía

Hz measurement mode to get correct
readings.
To Measure frequency (Hz):
•Select the Hz setting with the rotary
switch.
Insert:
•BLACK LEAD IN COM JACK.
•RED LEAD IN RPM, V, Ω jack.
Connect:
•The Black test probe to GROUND side.
•The Red test probe to the "SIGNAL
OUT" wire of the object to be tested.
NOTE: The display will show 00.00Hz for
frequencies below 0.5Hz.
6. BASIC AUTOMOTIVE
DIAGNOSTIC TESTING
These basic diagnostic tests begin by
checking the main source of power and the
chassis ground circuit connections. Ground
circuits are one of the least understood
but potentially most troublesome areas of
automotive electronics.
REFERENCE
VOLTAGE SIDE
SIGNAL
OUT GROUND
RED (+)
BLACK (+)
One of the most frustrating electrical
problems you will encounter in an
automobile is a high resistance ground.
This can create some very strange
symptoms that seem to be unrelated to the
cause. The symptoms can include problems
with turn signals, lights that stay dim,
the wrong lights turning on, transmission
shifting problems, gauges that change
when certain accessories are operated,
or even lights that will not turn on at all.
You can find a bad ground by checking the
voltage between the component's ground
wire and a clean chassis ground or the
negative vehicle battery terminal.
An excessive voltage drop in a ground
circuit affects the entire electrical circuit.
This is why it is so important to make sure
the basic circuits are in computer and
individual components.
Battery Tests
No Load Test
This test checks for battery charge state. A
fully charged battery will display at least
12.6V. Since voltage tests only show the
charge state, not the battery condition,
you should also perform a load test to
indicate the battery's performance.
To check battery charge state:
• Turn the headlights on for 15 seconds to
dissipate battery surface charge.
• Disconnect the negative (–) battery cable
terminal.
• Set the rotary switch to voltage ( ).
E N G L I S H
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