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AUTOOL DM303 Digital Multimeter Car Circuit Tester
AUTOOL DM303 auto diagnostic multimeter with oscilloscope ignition pulse K CAN line data color display and portable toolbox
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  1. AUTOOL DM303 Digital Multimeter Car Circuit Tester
  2. AUTOOL DM303 auto diagnostic multimeter with oscilloscope ignition pulse K CAN line data color display and portable toolbox
  3. AUTOOL DM303 Digital Multimeter Circuit Tester
  4. AUTOOL DM303 Digital Multimeter Circuit Tester
  5. AUTOOL 18 PCS Adapter connectors
  6. AUTOOL DM303 Digital Multimeter Circuit Tester
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  8. AUTOOL CT450 Ultrasonic Fuel Injector Cleaner
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  10. AUTOOL SDT103 Smoke Tester
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AUTOOL DM303 Digital Multimeter Car Circuit Tester

US$190.00

Key Features
  • K/CAN Test
  • Oscilloscope Mode
  • Injector Test
Key Features
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AUTOOL DM303

Product Overview

AUTOOL DM303 is a handheld automotive diagnostic multimeter that integrates a digital multimeter, oscilloscope, automotive circuit tester, cranking test, injector test, relay test, analog signal output, ignition pulse test, and K/CAN line data reading for vehicle electrical diagnosis.

Digital Multimeter 500kHz Oscilloscope K/CAN Line Data Injector / Relay Test
2.8-inchColor Display
DC 0-1000VVoltage Range
1Hz-1MHzFrequency Range
3 YearsWarranty
AUTOOL DM303 auto diagnostic multimeter with multimeter oscilloscope ignition pulse K CAN line data color display and toolbox features Click to enlarge
Before You Order And Use

Before You Order And Use

DM303 and DM301 are shipped without batteries. Confirm the battery type before use, and do not charge dry batteries inside the device.

Batteries Are Not Included

DM303 / DM301 is shipped without batteries due to shipping and battery restrictions. Batteries need to be purchased separately.

Dry Battery Option

You can install 4pcs 1.5V dry batteries for normal use. Do not charge dry batteries through the device.

Lithium Battery Option

You may install a compatible lithium battery by yourself. The reference image shows a 503450 3.7V 1000mAh lithium battery style.

Charge Only Lithium Setup

If a compatible rechargeable lithium battery is installed, it can be charged. Dry batteries must not be charged.

Battery Safety Reminder

  • Do not mix dry batteries and rechargeable lithium battery setups.
  • Confirm the battery direction, voltage, and connector style before installation.
  • Contact AUTOOL Store if you are not sure whether your lithium battery is compatible.
Compatible lithium battery style reference for AUTOOL DM301 and DM303 Click to enlarge
Product Comparison

Product Comparison

DM303 is the more advanced choice if you need more automotive diagnostic modes, more wiring options, injector and relay tests, cranking test, analog signal output, automotive circuit testing, and K/CAN related line data checks.

Function LevelDM301 focuses on basic measurement and oscilloscope-style checks. DM303 adds advanced automotive diagnostic modes such as injector, relay, circuit, cranking, analog signal, CAN line, and K/LIN-related data reading.
Measurement ModesThe comparison chart lists DM301 with 6 basic functions and DM303 with 12 function types. DM303 is better for complex vehicle electronic control system diagnosis.
Power SupplyDM301 supports dry battery, Type-C, and optional lithium battery configuration. DM303 further supports dry battery, Type-C, 12V rechargeable battery configuration, and optional lithium battery setup depending on installation.
AccessoriesDM303 provides more test lead types than DM301. It is more flexible for automotive circuit, injector, relay, signal, K/CAN, and multimeter testing scenarios.
Shared DesignBoth models have a 2.8-inch color screen, flashlight function, toolbox configuration, and support for trucks, sedans, buses, electric vehicles, and other vehicle types.
AUTOOL DM301 and DM303 auto diagnostic multimeter comparison chart Click to enlarge
Key Features

Key Features

DM303 combines standard electrical measurement with vehicle-focused circuit and signal tests, helping technicians check voltage, current, resistance, frequency, waveforms, starting voltage, injectors, relays, ignition signals, analog output, and K/CAN line data.

True RMS Auto-Ranging Multimeter

Measures DC / AC voltage, current, resistance, diode, and frequency. Auto range helps reduce manual range selection, while True RMS improves reading reliability for electrical testing.

500kHz Oscilloscope

The handheld oscilloscope supports 500kHz bandwidth and one-button automatic waveform display for observing slowly changing or automotive circuit signals.

Automotive Circuit Test

Supports automotive circuit voltage and drive-current checks. It can help check battery voltage, vehicle circuits, ECU-related wiring, and other electrical parts through the proper test leads.

Cranking Test

During vehicle starting, a minimum battery voltage above 9.6V is generally considered normal. If the value drops below 9.6V, the battery may be aging or weak.

Injector And Relay Test

DM303 can drive and detect injector signals, and can also support relay testing. It supports electromagnetic injectors including GDI injectors, but does not support 120V injectors.

Analog Signal And K/CAN Line Data

Supports 5V square wave, 5Vpp sine wave, and 12V square wave output with the proper cable and battery setup. K/CAN line data reading helps circuit-level diagnosis, but it is not a full vehicle scan tool.

AUTOOL DM303 12 test functions including voltage current resistance oscilloscope circuit cranking injector relay analog ignition K CAN and frequency Click to enlarge
AUTOOL DM303 interface display for multimeter oscilloscope circuit cranking injector relay analog ignition and K CAN line data Click to enlarge
AUTOOL DM303 2.8 inch color display with brightness and sleep time settings Click to enlarge
AUTOOL DM303 multilingual interface language support image Click to enlarge
AUTOOL DM303 portable toolbox for main unit and accessories Click to enlarge
Specifications

AUTOOL DM303 Product Specifications

DM303 supports wide voltage, current, resistance, and frequency ranges, plus automotive circuit drive current and injector drive signal output for vehicle electrical diagnosis.

Core Specifications
ProductAUTOOL DM303 Auto Diagnostic Multimeter
Display2.8-inch color screen
Voltage Measurement RangeDC 0-1000V, AC 0-700V
Current Measurement Range0-20A, 0-200mA
Resistance Measurement Range0-1MΩ
Frequency Measurement Range1Hz-1MHz
Automotive Circuit Drive Current0-5A
Injector Drive Signal Output500-6000rpm
Oscilloscope Bandwidth500kHz
Working Temperature0°C-40°C / 32°F-104°F
Power Supply MethodDry battery, Type-C, 12V rechargeable battery configuration, and optional lithium battery setup depending on installation
Data Lock / ClearSupported
Language SupportMulti-language interface including English, French, Portuguese, Polish, Spanish, Japanese, Russian, Italian, German, Dutch, Korean, Chinese, and other supported firmware options
Applicable Vehicle ModelsTrucks, sedans, buses, electric vehicles, and other vehicle types
Warranty3-year support for eligible non-human damage cases
Product Structure
Structure OverviewDM303 is designed for workshop and outdoor electrical diagnosis with a color screen, shortcut keys, multiple input ports, DB15 interface, built-in light, data interface, back bracket, and protective toolbox.
Screen And KeysDisplay screen, power key, hold key, direction keys, return key, enter key, function keys, measurement mode switching, and lighting key.
Measurement Ports10A current input, mA / μA measurement input, COM measurement input, and diode / voltage / resistance / frequency measurement input.
Diagnostic InterfacesDB15 interface, SD card slot / data interface, and back bracket for convenient display positioning during testing.
ToolboxThe plastic toolbox stores the main unit and accessories, helps protect the instrument, and makes it easier to carry to repair sites.
AUTOOL DM303 product specifications and dimensions image Click to enlarge
AUTOOL DM303 product details display screen keys measurement input DB15 interface light SD card slot and back bracket Click to enlarge
Core Specifications
ProductAUTOOL DM303 Auto Diagnostic Multimeter
Display2.8-inch color screen
Voltage Measurement RangeDC 0-1000V, AC 0-700V
Current Measurement Range0-20A, 0-200mA
Resistance Measurement Range0-1MΩ
Frequency Measurement Range1Hz-1MHz
Automotive Circuit Drive Current0-5A
Injector Drive Signal Output500-6000rpm
Oscilloscope Bandwidth500kHz
Working Temperature0°C-40°C / 32°F-104°F
Power Supply MethodDry battery, Type-C, 12V rechargeable battery configuration, and optional lithium battery setup depending on installation
Data Lock / ClearSupported
Language SupportMulti-language interface including English, French, Portuguese, Polish, Spanish, Japanese, Russian, Italian, German, Dutch, Korean, Chinese, and other supported firmware options
Applicable Vehicle ModelsTrucks, sedans, buses, electric vehicles, and other vehicle types
Warranty3-year support for eligible non-human damage cases
Product Structure
Structure OverviewDM303 is designed for workshop and outdoor electrical diagnosis with a color screen, shortcut keys, multiple input ports, DB15 interface, built-in light, data interface, back bracket, and protective toolbox.
Screen And KeysDisplay screen, power key, hold key, direction keys, return key, enter key, function keys, measurement mode switching, and lighting key.
Measurement Ports10A current input, mA / μA measurement input, COM measurement input, and diode / voltage / resistance / frequency measurement input.
Diagnostic InterfacesDB15 interface, SD card slot / data interface, and back bracket for convenient display positioning during testing.
ToolboxThe plastic toolbox stores the main unit and accessories, helps protect the instrument, and makes it easier to carry to repair sites.
AUTOOL DM303 packing list with main unit manual retail box toolbox and multiple test leads Click to enlarge
What Is In The Box

What Is In The Box

The packing list image shows the DM303 main unit, manual, retail box, portable toolbox, and multiple test leads. Batteries are not included and need to be purchased separately.

Main UnitAUTOOL DM303 auto diagnostic multimeter
StoragePortable protective toolbox and retail box
DocumentationUser manual shown in the package image
Test LeadsMultifunction test lead, battery clip cable, multimeter probes, jumper / adapter cables, and additional test leads shown in the package image
Battery NoticeBatteries are not included. Use 4pcs 1.5V dry batteries or a compatible lithium battery setup according to the battery rules.
Related Products

Related Products

Compare DM303 with related AUTOOL multimeter options before choosing a professional automotive diagnostic multimeter or a smaller general-purpose digital multimeter.

Manual And Downloads

Manual And Downloads

Download the DM303 manual for battery setup, test modes, wiring, interface operation, and safe-use guidance.

AUTOOL DM303 auto diagnostic multimeter user manual preview Click to enlarge

AUTOOL DM303 Manual PDF

Open the PDF manual before using advanced wiring, signal, injector, relay, K/CAN, and oscilloscope functions.

Download Manual

Need Function Or Battery Confirmation?

Contact AUTOOL Store before ordering if you need to confirm DM303 battery type, lithium battery charging, accessories, DM301 / DM303 differences, injector test limits, or K/CAN line data use.

Email[email protected] WhatsApp+86 189 2647 7404

Questions And Answers

These answers cover battery setup, charging limits, DM301 / DM303 differences, injector testing, cranking test results, measurement ranges, K/CAN line data, accessories, languages, and warranty support.

Related Guides

Related Guides

Use these related guides to learn more about AUTOOL electrical test tools, car battery checking, and fuel injector condition signs that may connect with DM303 diagnostic use cases.

Warranty And Contact

Warranty And Contact

For DM303 battery setup, lithium charging confirmation, DM301 / DM303 model selection, test lead confirmation, injector test limits, K/CAN line data use, manual support, accessories, or warranty service, contact AUTOOL Store directly.

Pre-Sales And Product Support

Use support if you need help confirming battery compatibility, charging rules, included accessories, language options, automotive circuit testing, analog signal output, injector / relay testing, or comparison with DM301 and other AUTOOL multimeters.

  • 3-year warranty for eligible non-human damage cases
  • Battery type and lithium charging confirmation
  • DM301 / DM303 model selection support
  • Package contents and test lead confirmation
  • Injector, relay, cranking, analog signal, and K/CAN function explanation
  • Manual download, setup guidance, and after-sales troubleshooting
Email Support[email protected] WhatsApp Support+86 189 2647 7404

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AUTOOL DM303 Digital Multimeter Car Circuit Tester
AUTOOL DM303 Digital Multimeter Car Circuit Tester

US$190.00

Select options This product has multiple variants. The options may be chosen on the product page Official Quote Request