UNI-T UT108, UT109 Operating Manual

P/N:110401102526

Operating Manual

UT108/109

Handheld Automotive Multi-Purpose Meters

UT108/109 OPERATING MANUAL

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Table of Contents

Title Page

Overview
Unpacking Inspection
Safety Information
Rules for Safe Operation
Automotive Servicing Safety Guide
International Electrical Symbols
The Meter Structure
Rotary Switch
Functional Buttons
Display Symbols
Measurement Operation
Part 1 Multimeter Basic Testing
A. AC/DC Voltage Testing
B. DC millvoltage Testing
C. AC/DC Current Testing
D. Resistance Testing
E. Continuity Testing

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Title Page

F. Diode Testing
G. Capacitance Testing
H. Frequency Testing
I. Temperature Measurement (UT109 only)
J. Dwell Testing
K. Engine Tach (Rotation Speed) Testing “RPMx10”
L. Operation of Hold Mode
M. RANGE button
N. MAX MIN button
O. Data Outputting
P. Display backlight
Q. The BLUE button
R. Automatic power off
Part 2 Diagnosis of Automotive Troubles
A. Fuse Testing: Check the fuse to see if it is blown out.
B. Switch Testing: Check the switch to see if it can work correctly.
C. Solenoid or Relay Testing
D. Starting/Charging System Testing

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E. Battery Power Consumption Testing when the Engine Is off
F. Trigger Voltage Battery Load Testing
G. Voltage Drop Testing
H. Charging System Voltage Testing
I. Ignition System Testing

1. Ignition Coil Testing

2. Ignition System High Voltage Damper Testing

3. Hall Switch/Sensor Testing

4. Magnetic Resistance Sensor

5. RPMx10 Testing

6. Fuel System Testing
J. Engine Sensor Testing

1. Oxygen Sensor

2. Temperature Sensor

3. Position Sensor

4. Absolute Pressure (MAP) and Baro Sensor

5. Mass Air Flow (MAF) Sensor

Title Page

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General Specications
Accurate Specications

A. DC Voltage
B. AC Voltage
C. DC millvoltage
D. AC Current
E. DC Current
F. Resistance
G. Capacitance
H. Frequency
I. Diode
J. Continuity
K. Dwell
L. Tach (Rotation Speed)
M. Temperature
Maintenance
A. General Services
B. Replacing the Fuses
C. Replacing the Battery

Title Page

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Overview

This Operating Manual covers information on safety and cautions. Please read the
relevant information carefully and observe all the Warnings and Notes strictly.

Warning
To avoid electric shock or personal injury, read the “Safety Information” and “Rules
for Safe Operation” carefully before using the Meter.

Automotive Digital Multimeter Model UT108/UT109 (hereafter referred to as “the Meter”)
is a 4000 counts, 3-3/4 digits manual ranging meter. The meter uses large scale of
integrated circuit with integrated A/D converter as its core. Spotting a unique design
with an extra large LCD display. Connect Test Leads display, full overload protection
and unique outlook design. For this reason, it emerges as an electric meter with more
outstanding performance for safer operation than other meters. In addition to the Dwell,
Tach and Data Hold feature, the Meter can be used to test the AC/DC voltage, AC/DC
current, resistance, frequency, diode, continuity, and Capacitance.

UT109 has an extra temperature feature.

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Unpacking Inspection

Open the package case and take out the Meter. Check the following items carefully to see
any missing or damaged part:

Item Description Qty

1 English Operating Manual 1 piece
2 Test Lead 1 pair
K-Type Point Contact Temperature Probe.
3 (UT109 only and It is only suitable for 1 pair
measuring temperature under 230℃)
4 Alligator Clip 1 piece
5 RS232C interface cable 1 piece
6 CD-ROM 1 piece
7 9V Battery (NEDA 1604, 6F22 or 006P) 1 piece
8 Multi-Purpose Socket ( Optional) 1 piece
9 USB interface cable ( Optional) 1 piece

In the event you nd any missing or damage, please contact your dealer immediately.

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Safety Information

This Meter complies with standards IEC61010: in pollution degree 2, overvoltage category
(CATIII 1000V, CATⅣ 600V) and double insulation.

CAT III: Distribution level, xed installation, with smaller transient overvoltages than CAT

IV
CAT IV: Primary supply level, overhead lines, cable systems ets.

Use the Meter only as specied in this operating manual, otherwise the protection

provided by the Meter may be impaired.

International electrical symbols used on the Meter and in this Operating Manual are
explained on page 13.

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Rules For Safe Operation

Warning
To avoid possible electric shock or personal injury, and to avoid possible damage to
the Meter or to the equipment under test, adhere to the following rules:

● Before using the Meter inspect the case. Do not use the Meter if it is damaged or the

case (or part of the case) is removed. Look for cracks or missing plastic. Pay
attention to the insulation around the connectors.

● Inspect the test leads for damaged insulation or exposed metal. Check the test leads

for continuity. Replace damaged test leads with identical model number or electrical

specications before using the Meter.

● When using the test leads, keep your ngers behind the nger guards.

● Do not apply more than the rated voltage, as marked on the Meter, between the

terminals or between any terminal and grounding.

● When the meter working at an effective voltage over 60V in DC or 30V rms in AC,

special care should be taken for there is danger of electric shock.

● Use the proper terminals, function, and range for your measurements.

● The rotary switch should be placed in the right position and no any changeover of

range shall be made during measurement is conducted to prevent damage of the

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Meter.

● Disconnect circuit power and discharge all high-voltage capacitors before testing,

resistance, diodes or continuity.

● Before measuring current, check the fuse is ok. Before connecting the Meter in serial

to the tested in-circuit, disconnect in-circuit power.

● If the value of current to be measured is unknown, use the maximum measurement

position, and reduce the range step by step until a satisfactory reading is obtained

● Replace the battery as soon as the battery indicator appears. With a low battery, the

Meter might produce false readings that can lead to electric show and personal injury.

● When servicing the Meter, use only the same model number or identical electrical
specications replacement parts.

● The internal circuit of the Meter shall not be altered at will to avoid damage of the

Meter and any accident.

● Soft cloth and mild detergent should be used to clean the surface of the Meter when

servicing. No abrasive and solvent should be used to prevent the surface of the Meter
from corrosion, damage and accident.

● Turn off the Meter when it is not in use and take out the battery when not using for a

long time.

● Do not use or store the Meter in an environment of high temperature, humidity,
explosive, inammable and strong magnetic eld. The performance of the Meter may

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deteriorate after dampened.

● The Meter is suitable for indoor use.

Automotive Servicing Safety Guide

Warning
As some automobiles are installed with safety air bags, you must pay attention to
the cautions in the automotive servicing manual when you are working around the
components and wiring of the air bags, or any carelessness will open an air bag,
resulting in some personal injury. Note that the air bag will also be opened for a few
minutes after the ignition lock is closed (or even when the automotive battery is cut
off), which is driven by the special energy reserve.

To prevent an accident from causing any personal injury or any damage to an automobile
or any of its meters, please read the following safety guidelines and testing procedure in
earnest:

● Wear protective eyeglasses which meet safety requirements.

● Operate the automobile in a well-ventilated place so as to prevent the inhalation of

any toxic tail gas.

● Keep your own tools and testing instruments far from all the heater components of the

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operating engine.

● Ensure that the automobile has stopped (automatic transmission) or put into neutral

gear (manual transmission) and be sure that it is equipped with brakes and the
wheels have been locked.

● Do not place any tool on the automotive battery which will cause a short circuit of the

electrodes and in turn lead to any personal injury or damage to a tool or battery.

● Smoking or striking a light near the automobile is prohibited.

● Pay attention to ignition coil, an ignition lead or a spark plug socket because these

components are provided with high voltages when the automobile is operating.

● To connect or cut off an electronic component, close the ignition lock.

● Pay attention to the automotive producer’s cautions, notes and servicing procedures.

All the information, explanations and detailed descriptions in the operation manual have
originated from the industrial information recently published. It is impossible to prove the
accuracy and completeness of the information, of which we shall not be responsible for
the assumption.

A.The data of the automotive servicing manual have originated from the automotive
servicing information.

1. Contact the local distributors of automotive components.

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2. Contact the local retailers of automotive components.

3. Contact the local libraries to look up any book for the proofreading of your automotive
servicing manual so as to provide you with the latest information.

B.before the diagnosis of any trouble opens the engine hood to make a thorough

visual inspection. You will nd the causes for many of your problems to be

solved, which will save you a lot of time.

1. Has the automobile recently been serviced? Has the same problem sometimes
occurred where the trouble lies?

2. Do not try to nd any short cut. Check the hoses and leads where it is probably very
difcult to nd out where any trouble lies.

3. Check any trouble with the air purier or pipeline system.

4. Check any damage to any sensor or the driving gear.

5. Check the ignition lead: any breakage of any terminal, crack on any spark plug or
breakage at the insulation of the ignition lead.

6. Check all the vacuum hoses: any right line, shrinkage, bend, crack, fracture or damage.

7. Check the leads: any connection of sharp edges, connection of hot surfaces (such as
exhaust manifold), shrinkage, burn or scratch at the insulation or right line connection.

8. Check circuit connections: any pin corrosion, bend or damage, inappropriate connection
position or damaged electrode lead.

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International Electrical Symbols

AC (Alternating Current).

DC (Direct Current)

Grounding.

AC or DC

Diode

Double Insulated.

Deciency of Built-In Battery.

Fuse.

Warning. Refer to the Operating Manual.

Conforms to Standards of European Union.

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The Meter Structure (see gure 1)

1. LCD display

2. Functional buttons

3. SELECT button
4 Power button
5 Rotary Switch
6 Input Terminals

(Figure 1)

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V

mV

℃
℉
Ω

Hz
uA
mA

A

RPM×10

Dwell

Rotary Switch

Below table indicated for information about the rotary switch positions.

AC or DC Voltage Measurement.
millvoltage Measurement.
The unit of temperature, ℃: Centigrade temperature (UT109 only)
The unit of temperature, ℉: Fahrenheit temperature (UT109 only)
Resistance Measurement.
Capacitance measurement
Continuity Test,
Diode Test.
Frequency Measurement,

Current measurement, unit: μA

Current measurement, unit: mA
Current measurement, unit: A
Automotive engine tach testing (Displayed Reading x 10), Unit: rpm
Automotive ignition dwell testing, Unit: degree

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Functional Buttons (see gure 2)

Below table indicated for information about the functional button operations

Figure 2

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Operation Performed

Turn the power on and off.

● Press HOLD once to enter hold mode.

● Press HOLD again to exit hold mode and the present value is shown.

● Press and hold for 2 seconds to turn the display backlight on or off.

Start recording of maximum and minimum values.

Press to step the display through high (MAX) and low (MIN) readings at

any time.

● Press once to enter Frequency measurement mode.

● Press and hold for 2 seconds to enter RS232C or USB mode.

● Press RANGE to enter the manual ranging mode;

● Press and hold RANGE for 2 seconds to return to auto ranging mode;

● Under RPM or Dwell testing mode, press RANGE to select 4CYL,

6CYL, or 8CYL.

Press SELECT to select the alternate functions.

Button

HOLD/

MAX/MIN

Hz

RANGE

SELECT

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Display Symbols (see gure 3)

Figure 3

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1 Data output is in progress.

2 The battery is low.

Warning: To avoid false readings, which could lead to possible

electric shock or personal injury, replace the battery as soon as the battery

indicator appears.

3 maximum or minimum reading displayed

4 4CYL, 6CYL, or 8CYL displayed

5 Test of continuity

6 Indicates for DC voltage or current

7 Indicates for AC voltage or current

8 Indicates for dangers

9 Data hold is active

10 The meter is in the auto range mode

11 The meter is in the auto range mode

12 Indicates for 841000mV range

13 Test of DWLL

14 Test of RPM

15 Indicates for units

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Measurement Operation

Part 1 Multimeter Basic Testing

A. AC/DC Voltage Testing (see gure 4)

Warning
To avoid harms to you or damages to the Meter from electric shock, please do
not attempt to measure voltages higher than 1000Vp although readings may be
obtained.
Please take extra care when measuring high voltages to avoid electric shock.
To measure DC voltage, connect the Meter as follows:

1. Insert the red test lead into the V terminal and the black test lead into the COM terminal.

2. Set the rotary switch to an appropriate measurement position in V , press BLUE
button to switch between AC and DC measurement mode.

3. AC voltage measurement display true rms value and press Hz button to obtain the
frequency value, input amplitude and frequency response refer to accuracy

specications.

4. Connect the test leads across with the object being measured.
The measured value shows on the display.

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Note

● If the value of voltage to be measured is unknown, use the maximum measurement

position (1000V) and reduce the range step by step until a satisfactory reading is
obtained.

● Please take extra care when measuring high voltages to avoid electric shock.

● In each range, the Meter has an input impedance of approx. 10MΩ. this loading effect

can cause measurement errors in high impedance circuits. If the circuit impedance is

less than or equal to 10kΩ, the error is negligible (0.1% or less).

● When voltage measurement has been completed, disconnect the connection between

the testing leads and the circuit under test, and remove the testing leading away from
the input terminals of the meter

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Figure 4

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B. DC millvoltage Testing (see gure 5)

Warning
To avoid harms to you or damages to the Meter from electric shock, please do
not attempt to measure voltages higher than the range although readings may be
obtained.
When AC voltage measurement has been completed, disconnect the connection
between the testing leads and the circuit under test.

To measure DC millvoltage, connect the Meter as follows:

1. Insert the red test lead into the V terminal and the black test lead into the COM terminal.

2. Set the rotary switch to an appropriate measurement position in .

3. Connect the test leads across with the object being measured.
The measured value shows on the display. Press Hz button to obtain the frequency

value, input amplitude and frequency response refer to accuracy specications.

4. The Meter has an input impedance of approx. 4000MΩ.

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Figure 5

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C. AC/DC Current Testing (see gure 6)

Warning
Before connecting the Meter in serial to the tested in-circuit, disconnect in-circuit
power.
If the fuse burns out during measurement, the Meter may be damaged or the
operator himself may be hurt.
Use proper terminals, function, and range for the measurement. When the testing
leads are connected to the current terminals, do not parallel them across any circuit
otherwise it will burn the fuse or damage to the Meter.

To measure AC/DC current, connect the Meter as follows:

1. Insert the red test lead into the “μA, mA” or “A” terminal and the black test lead into the
COM terminal.

2. Set the rotary switch to an appropriate measurement position in “μA, mA” or “A” .
Press blue button to switch between AC and DC measurement mode.

3. AC current measurement display true rms value and press Hz button to obtain the
frequency value, input amplitude and frequency response refer to accuracy

specications.

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4. Connect the test leads across with the object being measured.
The measured value shows on the display.

Note

● If the value of current to be measured is unknown, use the maximum measurement

position 10A terminal, and reduce the range step by step until a satisfactory reading is
obtained.

● When current measurement has been completed, disconnect the connection between

the testing leads and the circuit under test.

● When measuring 5A~10A: for continuous measurement ≤10 seconds and interval

time between 2 measurement greater than 15 minutes.

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Figure 6