AUTOOL DM303 Car Multimeter, Oscilloscope & Injector Tester

AUTOOL DM303 Automotive Diagnostic Multimeter

Advanced Automotive Electrical Testing Tool

The AUTOOL DM303 combines a digital multimeter, oscilloscope, circuit tester and signal generator in one handheld tool. It is built for mechanics and auto electricians who need to go beyond fault codes and confirm whether a sensor, injector, relay or circuit is actually working.

Use it to view sensor waveforms, drive injectors and relays off the car, check cranking voltage, and confirm CAN and K-Line signal activity. Suitable for 12V and 24V systems on cars, 4WDs, trucks and buses.

The AUTOOL DM303 Automotive Diagnostic Multimeter is a professional-grade handheld diagnostic tool engineered for advanced automotive electrical testing and fault analysis.

Main Features

12 test functions in one tool: voltage, current, resistance, frequency, oscilloscope, circuit, cranking, injector, relay, ignition pulse, signal simulation and CAN/K-Line checks.
Built-in oscilloscope: view crank, cam, oxygen sensor, wheel speed and ignition signals on the 2.8-inch colour screen.
Injector and relay drive: fire electromagnetic and GDI injectors (500–6000 rpm simulation) and switch relays off the vehicle to confirm they respond.
Signal simulation: 5V square, 5Vpp sine and 12V square outputs to test circuits and components.
Cranking test: records minimum battery voltage during starting to identify weak batteries or starting-system faults.
CAN and K-Line check: confirm communication line activity when diagnosing no-communication faults.
Circuit testing: supply power or ground to components with up to 5A drive current.
Auto-ranging multimeter: DC voltage to 1000V, AC voltage to 700V, current to 20A.

Important Notes

The DM303 is a testing tool, not a scan tool. It does not read fault codes or live data.
Not for use on high-voltage hybrid or EV systems.
Does not drive 120V piezo injectors.
Do not use the signal outputs on ECU outputs, airbag (SRS) circuits or powered data lines.
Requires 4 × AA batteries (not included).

Package Includes

AUTOOL DM303 Automotive Diagnostic Multimeter
Protective Carry Case
User Manual
Automotive Circuit Detection Lead
Oscilloscope & Signal Detection Harness
Battery Clip Power Cable
Injector & Relay Test Cable
Ignition Signal Detection Lead
K-Line Signal Lead
CAN+ Signal Lead
CAN− Signal Lead
Ground Wire Lead
Sine Wave Signal Lead
5V Signal Lead
Square Wave Signal Lead
Yellow Jumper Lead Set
Green Jumper Lead Set
Black Jumper Lead Set
Multimeter Test Probes
Probe Terminal Connector
DC Power Connector Cable

Why Mechanics Choose the DM303

Feature	Benefit
Multimeter + oscilloscope in one	One tool instead of two in the toolbox
Sensor waveform display	See intermittent or weak signals a standard meter misses
Injector drive (incl. GDI)	Confirm an injector fires before replacing it
Relay drive	Test relays on the bench in seconds
Cranking voltage test	Quickly separate battery faults from starter faults
CAN / K-Line signal check	Speeds up diagnosis of no-communication faults
5A circuit drive	Power fans, motors and lamps directly to test them
Signal simulation outputs	Feed known signals into circuits to isolate faults
12V and 24V support	Works on cars, 4WDs, trucks and buses

The AUTOOL DM303 integrates key testing capabilities, including voltage, current, resistance, oscilloscope analysis, circuit and cranking tests

AUTOOL DM303 Technical Specifications

Test Functions	12
Display	2.8-inch colour screen, adjustable brightness
DC Voltage	0–1000 V
AC Voltage	0–700 V
Current	0–200 mA; 0–20 A (10 A continuous)
Resistance	0–1 MΩ
Frequency	1 Hz–1 MHz
Circuit Drive Current	Up to 5 A
Injector Drive Output	500–6000 rpm simulation (electromagnetic and GDI; not 120 V piezo)
Signal Outputs	5 V square, 5 Vpp sine, 12 V square
Bus Testing	CAN and K/LIN line signal check (not a full vehicle scan)
Languages	13
Power	4 × AA 1.5 V batteries (not included)
Operating Temperature	0 °C to 40 °C
Warranty	3 years main unit, 1 year accessories (manufacturer)

AUTOOL DM303 automotive oscilloscope multimeter

Delivery

99% of purchases are dispatched from our Melbourne warehouse within 24 hours of payment. Every parcel is shipped with Australia Post e-Parcel, complete with tracking and signature on delivery.

Need it sooner? Express shipping is also available—check if your postcode is in the Next Day Delivery network.

Returns

Shop with confidence. We offer a 30-day money back guarantee on all orders. If you’ve had a change of mind, simply return the item in re-original condition and we’ll make it right.

Warranty

All AZscanners products are backed by a 12-month warranty (unless otherwise stated). We stand by the quality of our tools and will repair or replace your item if a covered fault arises.

Buying your scan tool should feel easy, safe, and backed by a team you can trust.

That’s why thousands of mechanics, fleets, and car owners across Australia choose AZscanners. Here’s our promise to you:

Trusted Since 2013

We’ve been Australia’s go-to supplier of premium diagnostic scan tools for over a decade. From workshops and mobile mechanics to DIY users, we’ve built our reputation on quality, reliability, and real support.

30-Day Money Back Guarantee

Changed your mind? No problem. You have 30 days to return your item in its original condition for a full refund. It’s our way of making your purchase completely risk-free.

Quality You Can Count On

Every product in our range is hand-picked for performance, compatibility, and durability. Whether you’re after a professional-grade scan tool or an easy solution for home use, we’ve got you covered.

Local Support that Cares

We don’t just sell scan tools — we support them. Our team of technicians is here to answer your questions before and after purchase, so you’re never left on your own.

Fast & Reliable Shipping

99% of orders are shipped within 24 hours (from our Melbourne warehouse) with tracking and signature included. Need it quicker? Express delivery is available.