Uni-Trend UT105 multimeter Specification

Model UT105: OPERATING MANUAL

Table of Contents

Title Page

Overview

Unpacking Inspection

Safety Information

Rules For Safe Operation

5

6

3

4

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 and DC Voltage Testing

B. DC Current Testing

C. Resistance Testing

D. Diode Testing

E. Continuity Testing

F. Dwell Testing

G. Engine Tach (Rotation Speed)

Testing “RPMx10”

8

11

12

13

14

15

17

17

17

18

20

21

23

24

25

26

27

H. Data Holding

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

27

27

28

28

E. Battery Power Consumption Testing

when the Engine Is off

F. Trigger Voltage Battery Load Testing

G. Voltage Drop Testing

29

30

31

1


Title Page

H. Charging System Voltage Testing 33

I. Ignition System Testing 34

1. Ignition Coil Testing

2. Ignition System High Voltage

Damper Testing

3. Hall Switch/Sensor Testing

34

35

4. Magnetic Resistance Sensor

5. RPMx10 Testing

6. Fuel System Testing

J. Engine Sensor Testing

36

37

38

39

1. Oxygen Sensor

2. Temperature Sensor

3. Position Sensor

4. Absolute Pressure (MAP) and

40

41

43

44

45 Baro Sensor

5. Mass Air Flow (MAF) Sensor

General Specifications

Accurate Specifications

47

49

50

50 A. DC Voltage

B. AC Voltage

C. DC Current

D. Resistance

50

50

51

51 E. Diode

F. Continuity Testing

G. Dwell Testing

H. Tach (Rotation Speed) Testing

51

52

52

Maintenance

A. General Services

B. Replacing the Fuses

C. Replacing the Battery

53

53

53

54

2


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.

In 1999 counts and 3-1/2 digits, the UT105 Meter is a manual testing automotive digital Multimeter. Spotting a unique design with an extra large screen, this meter has useful features such as a fully-functional symbol display, connect prompt, and full testing overload protection. For this reason, it emerges as an electric

Meter with more outstanding performance for safer operation than other Meters. In addition to the automotive dwell and tach (rotation speed), this Meter can be used to test the AC voltage, DC voltage, DC current, resistance, diode and continuity.

3


Unpacking Inspection

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

Item

1

2

3

4

Description

English Operating Manual

Test Lead

Alligator Clip

9V Battery (NEDA 1604, 6F22 or 006P)

Qty

1 piece

1 pair

1 pair

1 piece

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

4


Safety Information

This Meter complies with standards IEC61010: in pollution degree 2, overvoltage category (CAT. II 1000V, CAT. III

600V) and double insulation.

CAT.II: Local level, appliance, PORTABLE EQUIPMENT etc., with smaller transient overvoltages than CAT. III

CAT.III: Distribution level, fixed installation, with smaller transient overvoltages than CAT. IV

Use the Meter only as specified 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 11.

5


Rules For Safe Operation (1)

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: l 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.

l 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 specifications

before using the Meter.

l When using the test leads, keep your fingers

behind the finger guards.

l Do not apply more than the rated voltage, as

marked on the Meter, between the terminals or

between any terminal and grounding.

l When the Meter working at an effective voltage

over 60V in DC or 30V in AC, special care should

be taken for there is danger of electric shock.

l Use the proper terminals, function, and range

for your measurements.

l 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 Meter.

l Disconnect circuit power and discharge all

high-voltage capacitors before testing current,

resistance, diodes or continuity.

l 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 shock and personal injury.

6


Rules For Safe Operation (2)

7


8


Automotive Servicing Safety Guide(2) l To connect or cut off an electronic component,

close the ignition lock.

l 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.

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, open the engine hood to make a thorough visual inspection.

You will find 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 find any short cut. Check the hoses and

leads where it is probably very difficult to find out where

any trouble lies.

3. Check any trouble with the air purifier or pipeline system.

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

9


Automotive Servicing Safety Guide(3)

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.

10


International Electrical Symbols

AC (Alternating Current).

Grounding.

Double Insulated.

Deficiency of Built-In Battery.

Fuse.

Warning. Refer to the Operating Manual.

Conforms to Standards of European Union.

11


The Meter Structure (see figure 1)

1. LCD display

2. Data Hold button

3. Rotary Switch

4. Input Terminals

5. Power button

(figure 1)

12


Rotary Switch

Below table indicated for information about the rotary switch positions.

Rotary

Switch

Position

V

V

A

Function

DC voltage measurement.

AC voltage measurement.

DC Current Measurement

Diode test.

Continuity test.

Resistance measurement.

DWELL Automotive ignition dwell testing, Unit: degree

RPM x 10 Automotive engine tach (rotation speed) testing (Displayed Reading x 10), Unit: rpm

13


Functional Buttons

Below table indicated for information about the functional button operations.

AC voltage measurement.

Turn the power on and off.

HOLD l Press HOLD once to enter hold mode.

l Press HOLD again to exit hold mode

and the present value is shown.

l In Hold mode, is displayed

14


Display Symbols (see figure 2)

1

4

5

6

7

2

3

( figure 2)

8

4

5

6

No. Symbol Meaning

The battery is low.

1

Warning: To avoid false readings, which could lead to possible electric shock or personal injury, replace the battery as soon as the battery

2 AC indicator appears.

Indicator for AC voltage or current.

The displayed value is the mean value.

3 Indicates negative reading.

Test of diode.

The continuity buzzer is on.

Date hold is active.

7

Indicator of connecting test leads into different input terminals.

Connect

Terminal

15


Display Symbols(2)

(see figure 2)

No. Symbol Meaning

8

Ω

,k

Ω

,M

Ω

Ω:

Ohm. The unit of resistance.

k

Ω: kilohm.1 x 10

3

or 1000 ohms.

M

Ω:

Megaohm. 1 x 10

6

or

1,000,000 ohms.

mV, V

V: Volts. The unit of voltage.

mV: Millivolt. 1 x 10

-3

or 0.001 volts.

mA, A

A: Amperes (amps). The unit of

current.

mA: Milliamp. 1 x 10

-3

or 0.001

amperes.

DWELL Test of Dwell.

RPM x10 Tach x 10.

4CYL,

6CYL,

Number of cylinders.

8CYL

16


Measurement Operation(1)

Part 1 Multimeter Basic Testing

A.AC or DC Voltage Testing (see figure 3)

(figure 3)

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.

The DC voltage ranges are: 200.0mV, 2.000V, 20.00V,

200.0V and 1000V.

The AC voltage ranges are: 2.000V, 20.00V, 200.0V and

750V

To measure DC or AC 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 . or V

3. Connect the test leads across with the object being

measured.

The measured value shows on the display.

17



Note l 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.

l The LCD displays “1” indicating the existing selected

range is overloaded, it is required to select a higher

range in order to obtain a correct reading.

l In each range, the Meter has an input impedance of

approx. 10M

Ω

. This loading effect can cause

measurement errors in high impedance circuits. If the

circuit impedance is less than or equal to 10k

Ω

, the

error is negligible (0.1% or less).

When DC voltage measurement has been completed,

disconnect the connection between the testing leads

and the circuit under test.

B.DC Current Testing (see figure 4)

(figure 4)

Warning

Never attempt an in-circuit current measurement where the open circuit voltage between terminals and ground is greater than 250V .

If the fuse burns out during measurement, the Meter

18


Measurement Operation(3) 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.

The measurement ranges of DC current are: 200.0mA

and 10.00A.

To measure current, do the following:

1. Turn off power to the circuit. Discharge all high-

voltage capacitors.

2. Insert the red test lead into the mA or 10A terminal

and the black test lead into the COM terminal.


position in A r .

4. Break the current path to be tested. Connect the red

test lead to the more positive side of the break and

the black test lead to the more negative side of the

break.

5. Turn on power to the circuit.


Note l If the value of current to be measured is unknown,

use the maximum measurement position (10A) and

10A terminal, and reduce the range step by step until

a satisfactory reading is obtained.

l When DC current measurement has been completed,



l At 10A Range: for continuous measurement 10

seconds and interval time between 2 measurements

greater than 15 minutes.

19



C.Resistance Testing (see figure 5)

(figure 5)

Warning

To avoid damages to the Meter or to the devices under test, disconnect circuit power and discharge all the high-voltage capacitors before measuring resistance.

Never attempt an in-circuit current measurement where the open circuit voltage between terminals and ground is greater than 60V DC or 30V AC rms.

The resistance ranges are: 200.0

Ω

, 2.000k

Ω

, 20.00k

Ω

,

200.0k

Ω

, 2.000M

Ω and 20.00M

Ω

.

To measure resistance, connect the Meter as follows:

1. Insert the red test lead into the

Ω

terminal and the



position in

Ω

range.


measured.


20



Note l The test leads can add 0.1

Ω to 0.2

Ω

of error to the

resistance measurement. To obtain precision

readings in low-resistance, that is the range of 200

Ω

,

short-circuit the input terminals beforehand and

record the reading obtained (called this reading as

X). (X) is the additional resistance from the test lead.

Then use the equation:

measured resistance value (Y) – (X) = precision

readings of resistance.

l When the resistance reading 0.5

Ω in the short-circuit

condition, please check for loose test leads or other

reasons.

l For high resistance (>1M Ω

), it is normal taking several

seconds to obtain a stable reading, and it is better to

choose shorter test lead.

l When there is no input, for example in open circuit

condition, the Meter displays “1”.

l When resistance measurement has been completed,



D.Diode Testing (see figure 6)

(figure 6)

21



Warning

To avoid possible damage to the Meter and to the device under test, disconnect circuit power and discharge all high-voltage capacitors before testing diodes and continuity.


Use the diode test to check diodes, transistors, and other semiconductor devices. The diode test sends a current through the semiconductor junction, then measures the voltage drop across the junction. A good silicon junction drops between 0.5V and 0.8V.

To test a diode out of a circuit, connect the Meter as follows:

1. Insert the red test lead into the terminal and the


2. Set the rotary switch to .

3. For forward voltage drop readings on any semiconductor

component, place the red test lead on the component’s

anode and place the black test lead on the component’s

cathode.

The measured value shows on the display .

Note l In a circuit, a good diode should still produce a

forward voltage drop reading of 0.5V to 0.8V; however,

the reverse voltage drop reading can vary depending

on the resistance of other pathways between the probe

tips.

l Connect the test leads to the proper terminals as

said above to avoid error display.

l The open-circuit voltage is around 2.7V when testing

diode.

22


Measurement Operation(7) l The LCD will display 1 indicating open-circuit for

wrong connection.

l The unit of diode is Volt (V), displaying the positive-

connection voltage-drop value.

l When diode testing has been completed, disconnect

the connection between the testing leads and the

circuit under test.

E.Continuity Testing (see figure 6)

Warning

To avoid possible damage to the Meter and to the device under test, disconnect circuit power and discharge all high-voltage capacitors before testing diodes and continuity.


To test for continuity, connect the Meter as below:

1. Insert the red test lead into the terminal and the


2. Set the rotary switch to .


measured.

The buzzer does not sound when the resistance value is >50. The circuit is disconnected.

The buzzer sounds continuously when the resistance value is 30

Ω

. The circuit is in good condition.

Note l The LCD displays 1 indicating the circuit being tested

is open.

l Open-circuit voltage is approx. 2.7V.

l When continuity testing has been completed,



23



F.Dwell Testing (see figure 7)

It was very important in the past to test the dwell of the cut-off switch of an ignition system. The dwell testing means the duration when the cut-off switch remains off when the cam is turning. Now as an automobile is ignited electronically, it is no longer necessary to adjust the dwell.

In addition, the dwell testing can also be used to test a mixed-controlled solenoid.

(e.g. GM feedback carburetor).

1. Set the rotary switch to DWELL .

2. As prompted at the LCD connect terminal, insert the

red test lead into the terminal and the black test lead

into the COM terminal. Connect the ends to be tested

as illustrated.

l If the cut-off switch of an ignition system is

tested, connect the red test lead probe to the

primary negative end of the ignition coil.

(Refer to the automotive servicing manual for

the specific position.)

24



l If the GM feedback carburetor is tested, connect

the red probe to the ground terminal or the

computer drive of the solenoid. (Refer to the

automotive servicing manual for the specific

position.)

l If the dwell of an arbitrary ON/OFF equipment

is tested, connect the red probe to the end of

the equipment, fixed with an ON/OFF switch.

3. Connect the black test lead probe to the good ground

terminal of the automobile.

4. Read the ignition dwell of the tested automobile

directly from the display.

G.Engine Tach (Rotation Speed) Testing “RPMx10”

(see figure 8)

(figure 8)

The RPM means the rotating frequency of the main shaft of the engine per minute.

1. Set the rotary switch to RPMx10.


red test lead into the terminal and the black one

into the COM terminal. Select an appropriate number

of cylinders. Connect the ends to be tested as illustrated.

25



l If a DIS ignition system without any distributor

board is used in the automobile, connect the red

test lead probe to the TACH (tachometer) signal

line (which is connected to the computer DIS

module of the automotive engine). Refer to the

automotive servicing manual for the specific

position.

l If an ignition system with a distributor board is

used in the automobile, connect the red test lead

probe to the primary negative end of the ignition

coil. (Refer to the automotive servicing manual for

the specific position.)

3. Connect the black test lead probe to the good ground

terminal of the automobile.

4. Upon the start of the engine or during its operation, test

the rotation speed of the engine and read the displayed

value from the display. The actual rotation speed of the

automobile to be tested should be equal to the displayed

value multiplied by 10. For example, the actual rotation

speed of the engine of the automobile should be 2000

RPM (200 x 10) if the displayed value is 200 and the

meter is set at the 6CYL (6 cylinders) notch.

H.Data Holding

Under any testing circumstances, the display of the meter holds the testing result as soon as the HOLD is pressed down. When the HOLD is pressed once more, the testing result held in the display of the meter will be unlocked immediately and the meter randomly shows the current testing result.

26



Part 2 Diagnosis of Automotive Troubles

The digital multimeter is a tool for the very effective diagnosis of the troubles with the electronic systems of the automobile. This part gives a special introduction as to how the multimeter is used to diagnose any trouble with a fuse, switch, solenoid, relay, starting and charging systems, ignition system, fuel system and engine sensor.

A.Fuse Testing: Check the fuse to see if it is blown out.

1. Set the rotary switch to 200

Ω

.


red test lead into the

Ω terminal and the black one into

the COM terminal.

3. Short circuit the red and black test lead probes, when

the reading of the meter should be displayed between

0.2

Ω and 0.5

Ω

If it is more than 0.5

Ω

, check the test

leads to see whether they are well connected.

4. Connect the red and black test lead probes in parallel

to the two ends of the fuse, when the reading of the

meter should be displayed less than 10

Ω

, indicating

that the fuse is good. When the display is overload

“1”, it is shown that the fuse has been blown out.

l

It must be replaced with a fuse of the same type

and size.

B.Switch Testing: Check the switch to see if it can

work correctly.

1. The same as in Items 1 to 3 (Fuse Testing).

2. Connect the black test lead probe to one end of the

switch and the red one to another end. When the

switch is connected, the reading of the meter should

be displayed less than 10

Ω

. When the switch is cut

off, overload “1” should be displayed as the reading

of the meter.

27



C.Solenoid or Relay Testing

1. The same as in Items 1 to 3 (Fuse Testing).

2. Connect the red and black test lead probes in parallel

to the two end of a solenoid or relay. The impedance

of most of solenoids or relay coils is less than 200

Ω

.

(See the details in the automotive manual.)

Warning: l Both ends of a general solenoid or relay are

connected with diodes.

l Check to see if there is any damaged coil. Even

if the coil is found satisfactory, the solenoid or

relay may still be damaged. The relay may be

welded or worn due to the frequent sparking of

the contacts. The solenoid may be stuck when

the coil is in an on-position. Therefore some

potential problems cannot be found in testing.

D.Starting/Charging System Testing

The on-off package of the engine starting system consists of a battery, engine starting button, solenoid and relay starting buttons, lead connections and lines. During the operation of the engine, the charging system keeps the battery charged. This system consists of an AC generator, voltage calibrator, lead connections and circuits. The multimeter is an effective tool for the checking of these systems.

1.Load-Free Battery Testing

Before testing the starting/charging system, test the battery to see if it is fully charged.

(1) Set the rotary switch to 20 VDC.

28



(2) As prompted at the LCD connect terminal, insert the

red test lead into the V terminal and the black one

into the COM terminal.

(3) Turn off the ignition switch.

(4) Turn on the driving lights for 10 sec. to release charges

from the battery.

(5) Connect the black test lead probe to the negative

pole of the battery and the red one to the positive

pole of the battery.

2.The testing results are shown in contrast as follows and if the battery is less than 100%, please use it after charging it.

12.60 V 100%

12.45 V 75%

12.30 V 50%

12.15 V 25%

E.Battery Power Consumption Testing when the

Engine Is off

The test is carried out to find the amperage of the power consumption of the battery when both the ignition key and the engine are off. The test is helpful for the determination of the additional consumption of the battery, which may finally lead to the exhaustion of the battery.

29



Voltage Temperature

9.6 V or more 21.1

o

C (70 o

F)

9.5 V 15.6

o

C (60 o

F)

9.4 V 10.0

o

C (50 o

F)

9.3 V 4.4

o

C (40 o

F)

9.1V -1.1

o

C (30 o

F)

8.9 V -6.7

o

C (20 o

F)

8.7 V -12.2

o

C (10 o

F)

8.5 V -17.8

o

C (0 o

F)

G.Voltage Drop Testing

Test the voltage drops caused by the switch, cable, solenoid or connector. Any abnormal voltage drop generally results from an additional resistance. The resistance will restrict the currents upon the start of the engine, leading to the reduction of the load voltage of the battery and the slow-down of the start of the engine.

1.Cut off the ignition system so as to disable the start of the automobile.

Cut off the main ignition coil, shunt coil, cam and starting sensor so as to cut off the ignition system. Operate by reference to the automotive manual.

31



2.Set the rotary switch of the multimeter to the 200mV or 2VDC. As prompted at the LCD connect terminal, insert the red test lead into the V terminal and the black one into the COM terminal.

3.Refer to the LOSS typical trigger voltage circuit.

(See the details in figure 9)

Test the voltage between any of the following pairs of points respectively:1&2, 2&3, 4&5, 5&6, 6&7, 7&8, 8&

9, 8&10

Starter

Component Voltage

Switch 300 mV

Lead 200 mV

Grounding 100 mV

Battery Lead Connector 50 mV

Wiring 0.0 V

Compare the readings of the tested voltages against the said table. If the voltage is on the high side, check the components and connectors to see if there is anything wrong. If anything wrong is found, do necessary servicing.

32



H.Charging System Voltage Testing

This testing is used to see if the charging system operates normally so as to provide the electronic systems with adequate power (lamps, electric fans, radio sets, etc.).

1. Set the rotary switch of the multimeter to the 20VDC

As prompted at the LCD connect terminal,

insert the red test lead into the V terminal and the

black one into the COM terminal.

2. Connect the black test lead probe to the negative

pole of the battery and the red one to the positive

pole of the battery.

3. Run the engine idle and close or turn off all the

accessories with the normal voltage readings being

13.2 V to 15.2 v.

4. Open the throttle and control the rotation speed of

the engine between 1800 RPM and 2800 RPM. The

voltage readings should be consistent with those in

(3) (with the difference being no more than 0.5 V).

5. Turn on the lamps, windshield wipers, fans and so

on to increase the loads of the electronic systems

with the voltage readings being no less than 13.0 V.

6. If the readings in Steps 3., 4. and 5. are normal, the

charging system is also normal. If the readings in

Steps 3., 4. and 5. are beyond the limits or inconsistent

with those in the operation manual, check the current

ranges of the conveying belt, regulator, AC generator,

connector and open-circuit AC generator. If any further

diagnosis is required, refer to various kinds of automotive

manuals.

33



I.Ignition System Testing

1.Ignition Coil Testing

(1) Before the operation, cool the engine and cut off the

ignition coil.

(2) Set the rotary switch of the meter to the 200

Ω

. As

prompted at the LCD connect terminal, insert the red

test lead into the

Ω terminal and the black one into the

COM terminal. Test the primary coil of the ignition coil.

(3) Short circuit the red and black test lead probes. Their

short circuit resistance should be less than 0.5

Ω

. If it is

more, check the test lead to see if it is loose or damaged.

If it is damaged, replace it with a new one.

(4) Connect the red test lead probe to the primary “+” pole

of the ignition coil and the black one to the primary “-”

pole of the coil. (see figure 10.) See the detailed positions

in various kinds of automotive manuals.

figure 10 Secondary Coil

Warning: l The reading of the testing becomes the actual tested

resistance only after the reduction of the short-

circuit values of the test leads.

l The primary resistance is generally between 0.3 Ω

and 2.0

Ω

.

34



(5) Set the rotary switch to the 200k

Ω

and test the secondary

coil of the ignition coil.

(6) Connect the red test lead probe to the secondary

outlet and the black one to the primary “-” pole. Refer

to various kinds of automotive manuals for the details.

(7) The secondary resistance is generally in a range of 6 k

Ω

to 30 k

Ω

. Refer to various kinds of automotive manuals

for the details.

(8) For a heater ignition coil, repeat the said testing steps.

Note: For a heater ignition coil, the resistance may

be a little higher because the resistance of a coil will

vary with the temperatures. The higher the temperature,

the higher the resistance will be and vice versa.

2. Ignition System High-Voltage Damper Testing

(see figure 11)

(1) Move the connectors of the ignition system from the

engine. Refer to the ignition system movement

procedure in various kinds of automotive manuals for

the details.

35



Warning: l Some of Chrysler’s products use a spark plug

high voltage damper with “positive lock” end

electrodes, which can only be moved out of the

distributor board. If it is moved out of anywhere

else, some damage will result. Refer to various

kinds of automotive manuals for the details.

(2) Set the rotary switch of the meter to the 200 k

Ω

. As


test lead into the

Ω terminal and the black one into

the COM terminal.

(3) Connect the red and black test lead probes in parallel

to the two ends of the high-voltage damper and observe

the reading. The normal resistance is generally in a

range of 3 k

Ω

to 50 k

Ω

. In bending the lead, the reading

should remain unchanged.

3.Hall Switch/Sensor Testing (see figure 12)

When the tach and dwell are tested in the computer of the automobile, a Hall sensor is used. The Hall sensor is normally used in the ignition system to detect the position of the camshaft so that the computer of the automobile can set the optimal time for the ignition and the opening of the fuel injector.

36



(1) Move the Hall sensor out of the automobile and see

the details of the operation in various kinds of automotive

manuals.

(2) Connect the positive pole of the 9 V battery to the

source end of the sensor and the negative pole to the

ground end of the sensor by referring the details to

the positions of the source and ground ends of the

sensor in various kinds of automotive manuals.

(3) Set the rotary switch of the meter to 200

Ω

. As prompted

at the LCD connect terminal, insert the red test lead

into the

Ω

terminal and the black one into the COM

terminal.

(4) Connect the red and black test lead probes in parallel

to the signal connect terminal and ground end of the

sensor and the Meter should display a small ohm value.

(5) When a metal plate (blade, steel tape, etc.) is inserted

into a concave magnetic pole of the sensor, the display

of the meter will be enlarged or overloaded; if the metal

plate is moved away, the display will become smaller,

which proves that the sensor is satisfactory.

4.Magnetic Resistance Sensor (see figure 13)

37



The functions of a magnetic resistance sensor is similar to those of a Hall sensor and the testing methods of both sensors are also similar. Their normal resistance is generally in a range of 150

Ω

to 1 k

Ω

. Refer to the ranges of resistance in various kinds of automotive manuals for the details.

5.RPMx10 Testing (see figure 14)

(1) Set the rotary switch to RPMx10 and select the number

of cylinders in the automobile to be tested.

(2) As prompted at the LCD connect terminal, insert the

red test lead into the terminal and the black one

into the COM terminal.

(3) Connect the black test lead probe to the ground (i.e.

ground strap connection) of the automobile and the

red one to: the appropriate testing test terminal of

the computer of the automobile if the automobile is

in a DIS type (Refer to the servicing handbooks of

various kinds of automotive manuals for the detailed

position); or the negative pole of the ignition coil if the

automobile is equipped with a distributor board (Refer

to the servicing handbooks of various kinds of

automotive manuals for the detailed position).

38



(4) The normal starting rotation speed of an engine is

about 50 RPM to 275 RPM. Refer the detailed position

to the servicing handbooks of various kinds of automotive

manuals because this value relates to the current

temperature, engine size, battery size, etc.

Warning: l The displayed value of the meter becomes the

actual tach reading only after it is multiplied by 10.

6.Fuel System Testing

It is necessary to add more accurate engine fuel control to a low injection automobile. Since 1980, the automotive manufacturing industry has used electronically-controlled carburetor and fuel injection so as to achieve lower fuel injection.

(1) GM (General Motor): Testing the dwell of the C-3

mixed-control solenoid: Place the solenoid in a cylinder,

monitoring the ratio between the air and the fuel, which

should generally be 14.7 to 1 between the air and the

fuel so as to reduce the injection of surplus fuel. The

testing is used to see if the solenoid is installed right

in the position and the dwell of the meter can also

indirectly used for the testing.

A. Start the engine of the automobile to achieve a

rotation speed of 3000 RPM.

So far as a GM automobile is concerned, set the

rotary switch to the DWELL and select 6CYL.

B. When the automobile is operating in a short fuel

state or in a long fuel state, the dwell of the meter

should be displayed between 10 o

and 50 o

.

39



(2)Fuel Injector Resistance Testing (see figure 15)

The testing method is similar to that of the resistance of an ignition coil.

A. Cut the electric link off the injector.(Refer to the

servicing handbooks of various kinds of automotive

manuals for the detailed position.)

B. Connect the red and black test lead probes to the

two ends of the injector. The general normal resistance

is less than or equal to 10

Ω

.

J.Engine Sensor Testing (see figure 16)

40



To be adapted to the provisions for low injection and fuel saving in the early period of the eighties, the computercontrolled regulators were installed in the automobile and the sensors provided the computer with some data required. The multimeter is an effective tool for the detection of the operation of a sensor.

1.Oxygen Sensor

The oxygen sensor is used to test the oxygen content in the exhaust, giving rise to an appropriate voltage or resistance. A low voltage (high resistance) means a too high oxygen content in the exhaust, while a high voltage

(low resistance) means a too low oxygen content. The computer regulates the ratio between the air and the fuel according to the high or low voltage. There are normally two types of oxygen sensors: the zirconia and titania sensors.

(Refer to the different external properties of the two types for the details.)

Testing Procedure:

(1) Move the oxygen sensor out of the automobile.

(2) Set the rotary switch to 200

Ω

. As prompted at the

LCD connect terminal, insert the red test lead into

the

Ω terminal and the black one into the COM terminal.

(3) Connect the black test lead probe of the meter to the

ground terminal (i.e. cold end) of the sensor.

Warning: l If the sensor has a 1- or 3-lead outlet, the ground

terminal is its shell.

l If the sensor has a 2- or 4-lead outlet, the ground

terminal is its special wiring.

41



(4) Connect the red test lead probe of the meter to the

signal terminal (i.e. hot end) of the sensor.

If the sensor has more than 3 leads, what is used in the

automobile is a heat oxygen sensor, which has 2 hot

ends. Refer the positions of the hot ends in various

kinds of automotive manuals.

At this time, connect the red and black test lead probes

respectively to these two hot ends. Compare the readings

with the specifications in the operation manual provided

by the manufacturer.

The zirconia sensor is tested with the 2VDC. As


test lead into the V terminal and insert the black test

lead into the COM terminal.

The titania sensor is tested with the 200k

Ω

. As prompted

at the LCD connect terminal, insert the red test lead into

the

Ω

terminal and insert the black test lead into the COM

terminal.

Secure the sensor with a table vice, light up the propane

burner and add a heat sensor terminal. Make its

temperature about 660 o

F and exhaust the oxygen from

the sensor, when the readings can be obtained:

The zirconia sensor has a voltage of 0.6 V or more.

The titania sensor has a resistance of about 1

Ω

.

Move the burner away for heating, when the reading

can be obtained:

The zirconia sensor has a voltage of 0.4 V or more.

The titania sensor has a resistance of about 4 k

Ω

.

Warning: l In testing, the readings will vary with the heating

temperatures.

42



2.Temperature sensor (see figure 17)

The temperature sensor changes the output resistance through the changes in peripheral temperatures. The hotter the sensor is, the lower the resistance becomes.

The temperature sensor is generally used in engine braking, air ventilation, flow, fuel temperature and other equipment.

Testing Procedure:

(1) The same as in the resistance testing method.

(2) When the general temperature of a heating sensor

rises, its resistance will drop. The thermal resistance

of the temperature sensor of the automotive engine

is generally less than 300

Ω

.

43



3.Position Sensor (see figure 18)

The position sensor is an electrometer or variable resistance.

It is used for the computer monitoring of the position and direction of a mechanical device. The typical position sensors include throttle, exhaust recirculating EGR, blade air flow and other sensors.

Testing Procedure:

(1) The same as in the resistance testing method.

(2) Connect the red and black test lead probes respectively

to the signal test terminal and ground terminal. Refer

to various kinds of automotive servicing manuals for

its position and the resistance to be tested.

44



4.Absolute Pressure (MAP) and Baro Sensor (see figure 19)

The MAP sensor is used to change a pressure signal into a DC voltage or frequency one. All GM, Chrysler,

Honda and Toyota use DC voltage type MAP sensors, while Ford uses frequency type MAP sensors. Refer to relevant manuals for other automotive manufacturers.

Testing Procedure:

(1) Connect the DC voltage type MAP sensor in the DC

voltage testing method and set the rotary switch of

the meter to 20 VDC.

(2) Connect the frequency type MAP sensor in the RPM

x10 testing method and set the meter to the number

of cylinders in the automobile.

45



(3) Taking 4 cylinders (4CYL) for example, connect the

black test lead probe of the meter to the ground

terminal (i.e. ground strap connection) and connect

the red one as illustrated in figure 20.

(4) Turn on the ignition key but do not start the engine.

Displayed Values:

DC Voltage Type Sensor:

In a vacuum state, the displayed value is generally between 3 V and 5 V. (The details shall be based on the parameters furnished by the supplier.)

Frequency Type Sensor:

In a vacuum state, the displayed value is generally 4770

RPM 5%. (This only applies to the MAP sensor produced by Ford and the other sensors shall be based on the parameters furnished by the supplier.)

Warning: l The reading becomes the actual RPM only after

it is multiplied by 10.

l Frequency = RPM/30. (This only applies to 4CYL.)

46



5.Mass Air Flow (MAF) Sensor (see figure 20)

The sensor converts the air flow into a DC voltage, low frequency or high frequency signal. UT105 can only be used to test a DC voltage or low frequency signal.

Testing Procedure:

(1) Connect the DC voltage type MAF sensor in the DC

voltage testing method and set the rotary switch of

the meter to 20VDC. Connect the frequency type

MAF sensor in the RPMx10 testing method and set

the meter to the number of cylinders in the automobile.

Now take 4 cylinders (4CYL) for example.

(2) Connect the black test lead probe of the meter to the

ground terminal (i.e. ground strap connection) and

connect the red one as illustrated in figure 21.

(3) Turn on the ignition key but do not start the engine.

47



Displayed Values:

DC Voltage Type Sensor:

The displayed value should be less than or equal to 1V.

(The details shall be based on the parameters furnished by the supplier.)

Frequency Type Sensor:

In a vacuum state, the displayed value should be 330

RPM 5%. (This only applies to GM low frequency sensors.)

The other low frequency sensors shall be based on the parameters furnished by the supplier.)

Warning: l The reading becomes the actual RPM only after it

is multiplied by 10.

l Frequency = RPM/30. (This only applies to 4CYL.)

48


General Specifications l Maximum Voltage between any Terminals and

grounding: Refer to different range input protection

voltage.

l Fuse Protection of

mA terminal : CE Version: 315mA, 250V,

fast type, 5x20mm l Fuse Protection of

10A terminal : CE Version: 10A, 250V, fast

type, 5x20mm l Measurement Speed : Updates 2-3 times /second.

l Maximum Display : 1999.

l Temperature : Operating: 0 o

C~40 o

C(32 o

F~104 o

F)

Storage: -10 o

C~50 o

C(14 o

F~122 o

F) l Relative Humidity : 75% @ 0 o

C to below 30 o

C;

50% @ 30 o

C to 40 o

C.

l Altitude: Operating : 2000m; Storage: 10000m.

l Battery Type : One piece of 9V (NEDA1604

or 6F22 or 006P).

l Electromagnetic

Compatibility : In a radio field of 1 V/m,

Overall Accuracy = Specified

Accuracy + 5% of Range;

in a radio field of more than

1 V/m, no assigned accuracy

is specified l Battery Deficiency : Display .

l Negative reading : Display .

l Overloading : Display 1.

l Equipped with full icons display.

l Manual ranging.

l Polarity: Automatically display.

l Dimensions (HxWxL) : 179 x 88 x 39mm.

l Weight : 380g. (including holster and

battery) l Safety/Compliances : IEC61010: CAT. II 1000V,

CAT. III 600V overvoltage

and double insulation standard.

l Certification :

49


Accurate Specifications(1)

Accuracy: (a% Reading + Digits), guarantee for 1 year.

Operating Temperature: 18 o

C to 28 o

C.

Relative Humidity: No more than 75% RH.

A.DC Voltage

Range Resolution Accuracy

200mV

2 V

20V

200V

1000V

0.1mV

1mV

10mV

100mV

1V

(0.5%+5)

(0.8%+5)

Remark: Input impedance: 10M

Ω

B.AC Voltage

Overload Protection

230VAC

1000 VDC or 750

VAC continuous

Range Resolution

2V

20V

200V

750V

1mV

10mV

100mV

1V

Accuracy

(0.8%+5)

(1.0%+4)


1000 VDC or 750

VAC continuous

Remarks: l Input impedance: 10M Ω

.

l Frequency response: 40Hz ~ 400Hz.

l Displays effective value of sine wave (mean value

response).

C.DC Current

Range Resolution Accuracy

200mA 0.1mA


(0.8%+5)

CE:Fuse 315mA, 250V, fast type, 5x20mm

10A 10mA (1.2%+5) CE:Fuse 10A, 250V, fast type, 5x20mm

Remarks: l At 10A Range:

For continuous measurement 10 seconds and interval time between 2 measurement greater than 15 minutes.

50



D.Resistance

Accuracy Range Resolution

200

Ω

2k

Ω

20k

Ω

200k

Ω

2M

Ω

20M

Ω

0.1

1

10

1k

Ω

100

10k

Ω

Ω

Ω

Ω

Ω

(0.8%+5)

(1.5%+5)

Overload

Protection

600Vp

E.Diode

Range Resolution Overload Protection

1mV 600Vp

Remarks: l Open circuit voltage approximate 2.7V

l The silicon PN junction normal voltage is about 500

mV to 800 mV

F.Continuity Testing

Range Resolution Overload Protection

1

Ω

600Vp

Remarks: l Open circuit voltage approximate 2.7V.

l The buzzer does not sound when the resistance

value is >50

Ω

. The circuit is disconnected.

l The buzzer sounds continuously when the resistance

value is 30

Ω

. The circuit is in good condition.

51



G.Dwell Testing


4CYL

6CYL

8CYL

0.1

o

Accuracy Overload Protection

(3%+5) 600 VP

Remark:

Input Amplitude: More than or equal to 10 V in direct impulse; more than or equal to 0.5 mS in width.

H.Tach (Rotation Speed) Testing


4CYL

6CYL

8CYL

10 RPM

Accuracy Overload Protection

(3%+5) 600 VP

Remarks: l Input Amplitude: More than or equal to 10 V in direct

impulse; more than or equal to 0.5 mS in width.

l Maximum Tach: 10000 RPM, Tach = Displayed

Reading x 10.

52


Maintenance(1)

This section provides basic maintenance information including battery and fuse replacement instruction.

Warning

Do not attempt to repair or service your Meter unless you are qualified to do so and have the relevant calibration, performance test, and service information.

To avoid electrical shock or damage to the Meter, do not get water inside the case.

A.General Service l Periodically wipe the case with a damp cloth and mild

detergent. Do not use abrasives or solvents.

l To clean the terminals with cotton bar with detergent,

as dirt or moisture in the terminals can affect readings.

l Turn the Meter off when it is not in use and take out

the battery when not using for a long time.

l Do not store the Meter in a place of humidity, high

temperature, explosive, inflammable and strong

magnetic field.

B.Replacing the Fuses (see figure 21)

Holster

Screw

(figure 21)

53


Maintenance(2)

Warning

To avoid electrical shock or arc blast, or personal injury or damage to the Meter, use specified fuses

ONLY in accordance with the following procedure.

To replace the Meter's fuse:

1. Turn the Meter off and remove all connections from

the terminals.

2. Remove the holster from the Meter.

3. Remove the 3 screws from the case bottom, and

separate the case top from the case bottom.

4. Remove the fuse by gently prying one end loose,

then take out the fuse from its bracket.

5. Install ONLY replacement fuses with the identical type

and specification as follows and make sure the fuse

is fixed firmly in the bracket.

Fuse 1: CE 315mA, 250V, fast type, 5x20 mm.

Fuse 2: CE 10A, 250V, fast type, 5x20 mm.

6. Rejoin the case bottom and case top, and reinstall

the 3 screws and holster.

Replacement of the fuses is seldom required. Burning of a fuse always results from improper operation.

C.Replacing the Battery (see figure 22)

Open up Screw battery

(figure 22)

54


Maintenance(3)

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.

To replace the Meter’s battery:

1. Turn the Meter power off and remove all connections

from the terminals.

2. Take the Meter out from the holster.

3. Remove the 3 screws from the case bottom, and

separate the case top from the case bottom.

4. Remove the battery from the battery connector.

5. Replace with a new 9V battery (NEDA1604, 6F22 or

006P).

6. Rejoin the case bottom and case top, and reinstall

the 3 screws and the holster.

** END **

This operating manual is subject to change without notice.

55


Copyright 2001 Uni-Trend International Limited.

All rights reserved.

Manufacturer: UNI-TREND TECHNOLOGY(DONG GUAN)LIMITED

Address: Dong Fang Da Dao, Bei Shan Dong Fang Industrial

Development District, Hu Men Town, Dong Guan City,

Guang Dong Province, China

Headquarters: Uni-Trend International Limited

Address: Rm901, 9/F, Nanyang Plaza 57 Hung To Road

Kwun Tong Kowloon, Hong Kong

Tel: (852) 2950 9168

Fax: (852) 2950 9303

Email: [email protected]

http://www.uni-trend.com

56

Uni-Trend UT105 multimeter Specification

Unpacking Inspection

Rules For Safe Operation (2)

International Electrical Symbols

Functional Buttons

Display Symbols(2)

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