Hella Gutmann MT-HV User manual

MT-HV
Operating Instructions
manuals
08.23

Table of contents Hella Gutmann
2 MT-HV
Table of contents
1. About these Operating Instructions ....................................................................................................... 4
1.1. Notes about the Use of these Operating Instructions............................................................................................... 4
2. Symbols Used....................................................................................................................................... 5
2.1. Marking of Text Parts ................................................................................................................................................. 5
2.2. Symbols on the Product ............................................................................................................................................. 6
3. User Information................................................................................................................................... 7
3.1. Safety precautions ...................................................................................................................................................... 7
3.1.1. General Safety Precautions ........................................................................................................................... 7
3.1.2. Safety Precautions for the MT-HV................................................................................................................. 7
3.1.3. Safety Precautions for High Voltage/Line Voltage ....................................................................................... 8
3.1.4. Safety Precautions – Chemical Burns ........................................................................................................... 8
3.1.5. Safety Precautions – Risk of Injury ............................................................................................................... 9
3.1.6. Safety Precautions for Hybrid/Electric Vehicles ........................................................................................... 9
3.2. Disclaimer of liability .................................................................................................................................................. 10
3.2.1. Burden of Proof on the User.......................................................................................................................... 10
3.2.2. Documentation............................................................................................................................................... 10
4. Device description ................................................................................................................................ 12
4.1. Delivery Contents........................................................................................................................................................ 12
4.1.1. Basic ............................................................................................................................................................... 12
4.1.2. Positive ........................................................................................................................................................... 12
4.1.3. Pro................................................................................................................................................................... 13
4.1.4. Checking Delivery Contents........................................................................................................................... 14
4.2. Intended Use................................................................................................................................................................ 14
4.3. Using the Bluetooth® Function .................................................................................................................................. 15
4.4. MT-HV.......................................................................................................................................................................... 15
4.5. High-voltage test lead ................................................................................................................................................ 18
4.6. User Communication .................................................................................................................................................. 18
5. Installation ........................................................................................................................................... 20
5.1. Connecting the MT-HV with the mega macs X .......................................................................................................... 20
6. Low-Voltage Measurements .................................................................................................................. 21
6.1. Inserting the MT 77 into the MT–HV........................................................................................................................... 21
6.2. Connecting the Test Lead to the MT 77...................................................................................................................... 22

Hella Gutmann Table of contents
MT-HV 3
6.3. Connecting the Current Clamp to Vehicle and MT 77 ................................................................................................ 22
7. High-Voltage Measurement ................................................................................................................... 24
7.1. Connecting the high-voltage test lead to the MT-HV ................................................................................................ 24
7.2. Performing High-Voltage Measurements ................................................................................................................. 25
8. General information .............................................................................................................................. 26
8.1. Care and maintenance ................................................................................................................................................ 26
8.2. Disposal....................................................................................................................................................................... 27
8.3. Technical data MT-HV ................................................................................................................................................. 28
8.4. Technical Data of the MT 77........................................................................................................................................ 29
8.5. FCC Compliance Statement........................................................................................................................................ 31

1. | About these Operating Instructions Hella Gutmann
4 MT-HV
1. About these Operating Instructions
Original operating instructions
In these instructions, we have clearly structured the most important information so that you can use your MT-HV quickly
and efficiently.
1.1. Notes about the Use of these Operating Instructions
These operating instructions contain important information relevant to operator safety.
Go to www.hella-gutmann.com/manuals to find all the manuals, instructions, references and lists about our diagnostic
devices, tools and much more.
Please also visit our Hella Academy under www.hella-academy.com and expand your knowledge with various online tuto-
rials and other training courses.
Please read the operating instructions entirely. Pay special attention to the first pages containing the safety instructions.
They are provided solely to assure your safety when working with the product.
When working with the product, it is recommended to read the individual work steps in the manual again to prevent haz-
ard of persons and equipment or operating errors.
The product shall be used exclusively by a qualified person. Information and knowledge included in this training is not ex-
plained in these operating instructions.
The manufacturer reserves the right to modify these instructions and the product itself without prior notice. We therefore
recommend checking it for any updates. These operating instructions must accompany the product in case of sale or any
other transfer.
These operating instructions shall be kept for the entire service life of the product and shall be accessible at any time.

Hella Gutmann Symbols Used | 2.
MT-HV 5
2. Symbols Used
2.1. Marking of Text Parts
DANGER
Text parts marked in this way indicate an imminent dangerous situation, which will lead to death or se-
vere injuries if not avoided.
WARNING
Text parts marked in this way indicate a possibly dangerous situation, which may lead to death or se-
vere injuries if not avoided.
CAUTION!
Text parts marked in this way indicate a possibly dangerous situation, which may lead to minor or
slight injuries if not avoided.
These symbols indicate rotating parts.
This symbol indicates dangerous electric voltage/high voltage.
This symbol indicates the risk of crushing limbs.
This symbol indicates a potential injury of the hand.
IMPORTANT
All texts labeled IMPORTANT refer to a hazard in the diagnostic device or environment. The advices or
rather instructions stated here must therefore be observed by all means.
NOTICE
Texts marked with NOTICE contain important and helpful information. It is recommended to observe
these texts.

2. | Symbols Used Hella Gutmann
6 MT-HV
Struck-through waste bin
This marking indicates that the product must not be discarded as domestic waste.
The bar underneath the waste bin indicates whether the product was "placed on the market" after 13
August 2005.
Refer to manual
This marking indicates that the user manual must always be read and always be available.
2.2. Symbols on the Product
DANGER
Text parts marked in this way indicate an imminent dangerous situation, which will lead to death or se-
vere injuries if not avoided.
WARNING
Text parts marked in this way indicate a possibly dangerous situation, which may lead to death or se-
vere injuries if not avoided.
CAUTION!
Text parts marked in this way indicate a possibly dangerous situation, which may lead to minor or
slight injuries if not avoided.
Refer to manual
This marking indicates that the user manual must always be read and always be available.
Direct current voltage
This symbol indicates direct current voltage.
Direct current voltage means that the electrical voltage does not change throughout a longer period of
time.
Polarity
This symbol indicates a plus connection of a voltage source.
Ground connection
This symbol indicates a ground connection of a voltage source.

Hella Gutmann User Information | 3.
MT-HV 7
3. User Information
3.1. Safety precautions
3.1.1. General Safety Precautions
• The MT-HV is exclusively intended for use on a vehicle. It is a precondition for the use of the MT-HV that the user has
knowledge of automotive technology and is therefore aware of the sources of danger and risks in the workshop and
on motor vehicles.
• An additional country-specific qualification is mandatory for performing high-voltage measurements.
• Please read the entire operating instructions thoroughly and, where necessary, the mega macs X user manual before
using the MT-HV.
• All notes apply which are given in the individual sections of the MT-HV operating instructions and in the user docu-
mentation of the mega macs X. All the symbols on the MT-HV and the following measures and safety precautions
shall also be observed.
• Furthermore, pay attention to all general instructions from labour inspectorates, trade associations and vehicle man-
ufacturers as well as all laws, legal ordinances and instructions which have to be commonly obeyed by a repair shop.
3.1.2. Safety Precautions for the MT-HV
Observe the following to avoid incorrect handling and injury to the user or destruction of the MT-HV arising from this:
• Protect the MT-HV and all connecting cables from hot parts.
• Protect the MT-HV and all connecting cables from rotating parts.
• Regularly check all connecting cables/accessory parts for damage (destruction of the MT-HV due to short circuit).
• Only use approved test prods and high-voltage test leads.
• Regularly and prior to every application, check the test prods and high-voltage test leads for damage (visual inspec-
tion).
• Do not remove the protective cap from the test prods during high-voltage measurements.
• Do not exceed the allowed operating and ambient temperatures.
• Keep the MT-HV away from fluids such as water, oil or gasoline. The MT-HV is not waterproof.

3. | User Information Hella Gutmann
8 MT-HV
• Protect the MT-HV from strong impacts and do not drop it.
• If the MT-HV shows signs of malfunction, immediately contact Hella Gutmann or a Hella Gutmann trading partner.
3.1.3. Safety Precautions for High Voltage/Line Voltage
It is a precondition for performing high-voltage measurements that the user has knowledge of automotive technology
and is therefore aware of the sources of danger and risks in the workshop and on motor vehicles. An additional country-
specific qualification is mandatory.
Very high voltages occur in electrical systems. Due to voltage flashover on damaged components, such as marten dam-
age or touching live components, the risk of electric shock is likely. Voltage flashover can occur e.g. on the primary and
secondary side of the ignition system, the connection to the vehicle, the lighting systems or the wiring harness with plug
connections. Therefore regard the following:
• Only use power supply cables with grounding contact.
• Only use a checked or the attached power cord.
• Always use the original cable set.
• Do not exceed the voltage limits indicated on the connecting cables.
• The voltage values to be measured must be shielded extra or even twice from dangerous line voltage. The voltage
limits printed on the test leads must not be exceeded. Pay attention that the allowed measuring range is not exceeded
when measuring positive and negative voltage at the same time.
• Regularly check cables and adapters for damage.
• Perform any assembly work such as the connection of the MT-HV to the vehicle or the replacement of components
only when ignition is switched off.
• Do not touch live components when the ignition is on.
3.1.4. Safety Precautions – Chemical Burns
In case of improper use electrolyte may escape from the battery and may cause chemical burn of eyes, respiratory system
and skin. Therefore regard the following:

Hella Gutmann User Information | 3.
MT-HV 9
• Wear personal protective equipment when working on the battery.
• If acid comes in contact with parts of the body or clothing, immediately rinse the parts concerned with plenty of water
and consult a doctor.
• Instantly consult a doctor if you have aspirated acid vapor.
3.1.5. Safety Precautions – Risk of Injury
When working on the vehicle, there is a risk of injury through rotating parts or rolling of the vehicle. Therefore regard the
following:
• Protect vehicle against rolling away.
• Additionally place gear selector lever of AT vehicles to park position.
• Deactivate the start/stop system to avoid an inadvertent engine startup.
• Only connect the the MT-HV to the vehicle when the ignition is switched off.
• Do not reach into rotating parts while the engine is running.
• Do not run cables near rotating parts.
• Check the high-voltage parts for damage.
3.1.6. Safety Precautions for Hybrid/Electric Vehicles
Any work on high-voltage systems is allowed only when wearing the corresponding personal protective equipment.
Very high tensions occur on hybrid and electric vehicles. Due to voltage flashover on damaged components, such as
marten damage or touching live components, the risk of electric shock is likely. High voltage at or in the vehicle can lead
to death in case of inattention. Therefore regard the following:
• Only the following qualified employees are allowed to de-energize the high-voltage system:
– High-voltage technician
– Skilled electrician for predetermined operations – Hybrid or rather electric vehicles
– Skilled electrician

3. | User Information Hella Gutmann
10 MT-HV
• Place and attach warning signs and barriers.
• Check the high-voltage system and the high-voltage lines for damage (visual inspection!).
• De-energizing the high-voltage system:
– Regard the manufacturer- and vehicle-specific regulations.
• Regard the vehicle manufacturer's instructions.
• Securing the high-voltage system against re-activation:
– Withdraw the ignition key and keep it safe.
– Keep the service disconnect plug in a safe place or secure the battery master switch against re-activation.
– Insulate the battery master switch, the plug connections etc. with dummy plugs, covering caps or insulating tape
with the corresponding warning notice.
• With the MT-HV or another approved measuring tool, test for absence of voltage. Even when the high-voltage system
is disconnected, residual voltage may still be present.
• Ground and short-circuit the high-voltage system (necessary only if voltage is higher than 1000 V).
• Voltage below 1000 V: Cover the parts which are close to the system or which are energized e.g. with insulating cloth,
hoses or plastic coverings. Voltage higher than 1000 V: Cover the parts with insulating plates/protective panels spe-
cially developed for this purpose so that sufficient protection against contact to adjacent parts is ensured.
• Regard the following before re-energizing the high-voltage system:
– All tools and utilities are removed from the hybrid/electric vehicle.
– Remove the grounding and short circuit of the high-voltage system. Do not touch any of the cables now.
– Attach the protective paneling that has been removed before.
– Remove the protective measures at the switching system.
3.2. Disclaimer of liability
3.2.1. Burden of Proof on the User
The burden of proof is on the user of the product, that he has paid attention to technical explanations, notes on operation,
equipment care as well as maintenance and safety without exception.
3.2.2. Documentation
The listed notes describe the most common causes of errors. However, there are often further causes of existing faults
which cannot be listed here, or there are further sources of error which as yet are unknown. The Hella Gutmann Solutions
GmbH does not accept any liability for failed, unnecessary or incorrectly performed repair work.

Hella Gutmann User Information | 3.
MT-HV 11
Hella Gutmann Solutions GmbH does not accept any liability for the use of data and information that is found to be incor-
rect or that was incorrectly displayed, or for errors that occurred inadvertently during the compilation of the data.
The Hella Gutmann Solutions GmbH will not take any liability arising from the errors and misuse mentioned before and
further losses of profit or company value thereof.
The Hella Gutmann Solutions GmbH does not accept any liability for damages or operational disruptions resulting from
failure to observe the operating instructions and the special safety precautions.
The burden of proof is on the user of the product, that he has paid attention to technical explanations, notes on operation,
equipment care as well as maintenance and safety without exception.

4. | Device description Hella Gutmann
12 MT-HV
4. Device description
4.1. Delivery Contents
4.1.1. Basic
Quantity Name
1MT-HV
1 Power adapter and power cord
1 USB cable (type C - type C)
1 Operating instructions
4.1.2. Positive
Quantity Name
1MT-HV
1 Power adapter and power cord
1 USB cable (type C - type C)

Hella Gutmann Device description | 4.
MT-HV 13
Quantity Name
1 High-voltage test lead black/red
1 Operating instructions
4.1.3. Pro
Quantity Name
1MT-HV
1 Power adapter and power cord
1 USB cable (type C - type C)
1 High-voltage test lead black/red
1 MT 77
1 Black/blue test lead
1 Red/black test lead
1 Operating instructions

4. | Device description Hella Gutmann
14 MT-HV
4.1.4. Checking Delivery Contents
Please check the delivery contents upon receiving your device so that complaints can be issued immediately regarding any
potential damage.
Proceed as follows to check the delivery contents:
1. Open the delivery package and check for completeness based on the delivery slip. If the package shows signs of ex-
ternal damage, open it in the presence of the delivery service and examine the MT-HV for hidden damage. Any dam-
age to the delivery package or damage to the MT-HV during transport must be documented by the delivery service in
a damage report.
2. Take the MT-HV out of the packaging.
CAUTION!
Danger of short circuit due to loose parts in or at the MT-HV
Danger of destruction of the MT-HV and/or the automotive electronics
Never put the MT-HV into operation if you suspect that there are loose parts in or on the module. If this is
case, contact the HellaGutmann repair service or a HellaGutmann trading partner immediately.
3. Check the MT-HV for mechanical damage and shake slightly to ensure that there are no loose parts inside.
4.2. Intended Use
The MT-HV is a mobile measurement module with which you can measure voltage, current, resistance and pressure.
You can use the MT-HV both for measuring high voltages and low voltages. Use the installed high-voltage measurement
module for high-voltage measurements. You can insert another measurement module into the MT-HV for low-voltage
measurements.
The MT-HV can be operated only in connection with the mega macs X of Hella Gutmann. The communication between
the mega macs X and the MT-HV is realized via Bluetooth®. Diagnostic devices from other manufacturers will not be
supported. The MT-HV is not suitable for the following repair work/voltage measurements:
• Electric appliances and devices
• Home electrics
• Power supply systems/line voltage
If the MT-HV is used in a way not authorized by Hella Gutmann, the protection of the MT-HV and the mega macs X may
be influenced.

Hella Gutmann Device description | 4.
MT-HV 15
4.3. Using the Bluetooth® Function
NOTICE
Alternatively, you can also operate the MT-HV with USB cable connected to the mega macs X.
The terms of use of the Bluetooth® function may be restricted or prohibited through law or corresponding legal regula-
tions in certain countries.
Observe the provisions in force in the respective country before using the Bluetooth® function.
4.4. MT-HV
Name
1Connecting the high-voltage test leads
Connect the red high-voltage test lead.
2Connecting the high-voltage test leads
Connect the black high-voltage test lead.
3Module slot
Insert another module (e.g. MT 77) into the module slot.
4Unlocking button
• Use the unlocking button to unlock and remove the MT-HV.
• Use the unlocking button to check if the inserted module is properly inserted.

4. | Device description Hella Gutmann
16 MT-HV
Name
5USB-C interface
6Ethernet interface
7Power supply socket
Connect a power adapter to the power supply socket to supply the MT-HV with voltage and to
charge the internal battery.
8High-voltage
This LED indicates if e.g. a high-voltage measurement process is active or if high voltage is ap-
plied to the test prods (e.g. in case of insulation resistance measurement).
The different status indications are explained in the section User Communication [}18].
9Battery status
This LED indicates the various battery charging states.
The different battery status display are explained in the section User Communication [}18].
10 Update
This LED indicates that an update is in progress.
11 Bluetooth®
This LED indicates that the MT-HV is connected via Bluetooth®.

Hella Gutmann Device description | 4.
MT-HV 17
Name
12 MT-HV status
This LED indicates e.g. if the MT-HV is active or ready for operation.
The different status indications are explained in the section User Communication [}18].
13 ON/OFF button
Switch the MT-HV on and off with the ON/OFF button.
Name
14 / 15 Ports Scope 2 (CH2)
Connect the test leads to Scope 2 (CH2) here.
• red = signal +
• black = signal -
16 ST3 connector
Connect the blue and the green clamp meter here.
17 / 18 Ports Scope 1 (CH1)
Connect the test leads to Scope 1 (CH1) here.
• blue = signal +
• black = signal -

4. | Device description Hella Gutmann
18 MT-HV
4.5. High-voltage test lead
Name
19 High-voltage test lead (red)
• 4-mm-test connection (safety connector) for manufacturer-specific test adapters
• incl. function button to start or to confirm measurements
20 High-voltage test lead (black)
4-mm-test connection (safety connector) for manufacturer-specific test adapters
21 Attachable test prod (black)
22 Attachable test prod (red)
4.6. User Communication
Meaning of the LEDs with different interactions:
Interaction LED
When the MT-HV is switched off and you briefly push ON/OFF, the yellow LED will light up until
the start procedure is completed.
• After the start procedure is completed, the LED is permanently green and the MT-HV is ready
for operation.
• When the MT-HV is switched on and you briefly push ON/OFF, the green LED will flash sev-
eral times until the MT-HV is shut down entirely.
If the connection is inactive or if there is no connection in battery mode, the MT-HV will switch off
after 2 minutes. Before that the red LED will light red for 60 seconds.
If an update is in progress, the LED will flash several times green until the update is finished.

Hella Gutmann Device description | 4.
MT-HV 19
Interaction LED
The green LED is permanently on if the high-voltage measurement is active.
The yellow LED is permanently on if high voltage is switched to the test prods.
The blue LED is permanently on if the MT-HV has Bluetooth® connection.
Explanation of the battery status display:
more than 40 % of entire charge
• The battery status indicator flashes green if the battery is being charged.
• The status indicator is permanently green if the battery is fully charged.
20 % to 40 % of entire charge
20 % or less (charging required!)
• The battery status indicator flashes red if battery charge is less than 10 %.

5. | Installation Hella Gutmann
20 MT-HV
5. Installation
This section describes how to connect the MT-HV with the mega macs X.
5.1. Connecting the MT-HV with the mega macs X
Initial setup:
Proceed as follows to connect the MT-HV with the mega macs X for the first time:
1. Connect the MT-HV with the supplied USB-C cable to the mega macs X.
ðThe mega macs X is recognizing the MT-HV automatically and is starting the pairing process.
2. Remove the USB-C cable.
ðNow the MT-HV is connected with the mega macs X.
NOTICE
Continuous operation:
The MT-HV is connected via Bluetooth® with the mega macs X.
There is a Wi-Fi connection between the display device (tablet etc.) and the mega macs X.