Electrical troubleshooting involves more than checking a single number. Technicians may need to measure voltage, current and resistance, observe changing sensor signals, or perform a supported component test to investigate a fault.
The AUTOOL DM109 automotive circuit tester brings a multimeter, single-channel oscilloscope and 0–5V signal simulation together in one portable kit. Designed primarily for conventional internal combustion vehicle repair, it includes a carrying case and testing accessories for use at the workbench or on the move.
Looking for pricing or help choosing a configuration? Chat with Hanna on WhatsApp →
See the DM109 in Action#
Watch the official product video for a closer look at the device and the demonstrated operations. Then explore the functions and application limits below to decide whether the DM109 suits your workshop.
Video not loading? Watch the official demonstration on YouTube ↗
Your DM109 Discount Code#
Shopping for a new circuit tester? Enter the code below at checkout when ordering your DM109.
DM109UETJN45G
Check eligibility and the applied discount at checkout before completing payment. Offer conditions apply.
Shop DM109 with Your Code → | Ask Hanna About the Offer
Start with Clear Polarity Identification#
Identifying what you are testing is the first step in electrical troubleshooting. The DM109 supports smart testing to identify voltage, current or resistance measurements. Probe polarity indication adds a quick visual reference.
- Red: Positive
- Green: Negative
This automotive circuit tester with multimeter functions supports everyday DC measurements and leakage-current checks. The maximum current test value is 18A. Use the device within its specified measurement ranges and operating conditions.
Application limit: DC testing only. AC testing is not supported.
Look Beyond a Single Voltage Reading#
A single measurement may not show how a sensor signal changes. The DM109’s single-channel oscilloscope collects sensor information and displays voltage changes, giving technicians a visual reference during troubleshooting.
The device also provides 0–5V signal simulation output for compatible testing procedures. Measurement, observation and signal simulation are available together in one handheld automotive electrical diagnostic tool.
Interpret signals alongside vehicle service information and actual operating conditions. Confirm the circuit’s input requirements and connections before applying a simulated signal.
Extend Your Exhaust System Checks#
The supplied thermocouple supports a temperature measurement range of -20°C to 600°C. Suitable applications include temperature checks on exhaust pipes and at appropriate locations before and after the catalytic converter.
For inspection tasks that require temperature information, this function adds another measurement option. Follow the probe requirements and the vehicle manufacturer’s testing procedure when taking and interpreting readings.
Test Supported 12V Port Fuel Injectors#
For supported conventional fuel injection systems, the DM109 provides 12V port fuel injector testing.
Direct injection injectors are not supported. If you are unsure about suitability, share your vehicle and injector details with Hanna to discuss the application.
Ask About Injector Compatibility →
Practical Features for the Repair Bay#
A 2.8-inch IPS display makes test information easy to view. The work light can be controlled as needed: press and hold the return button to switch it off.
The device accepts a 9–72V input supply and features dual automatic protection. An inline fuse on the main power cable adds protection when the device is used as instructed.
Input supply voltage and individual measurement ranges are different specifications. Follow the requirements for each test function.
Keep Your Accessories Together#
The DM109 automotive circuit tester kit comes in a carrying case for convenient storage and transport. Included accessories cover several common testing needs.
| Accessory | Purpose or details |
|---|---|
| Relay test leads | For supported relay testing operations |
| Multimeter test leads | For applicable electrical measurements |
| USB cable | Firmware upgrade connection; upgrade availability and timing are subject to official confirmation |
| Thermocouple | Temperature measurement |
| Main power cable | Device power connection with an inline fuse |
Optional 5m and 10m extension cables let you choose a working reach that suits your workshop layout and testing tasks.
The device supports 16 languages. Additional language customization may be available, subject to minimum order requirements and confirmation.
Discuss DM109 Language Customization →
Is the DM109 Right for Your Workshop?#
If your business primarily services conventional internal combustion vehicles and regularly handles the following tasks, the DM109 is worth a closer look:
- DC voltage, current, resistance and leakage-current checks;
- Sensor voltage observation and compatible 0–5V signal simulation;
- Supported 12V port fuel injector tests;
- Temperature measurement at suitable exhaust system locations;
- Work requiring portable storage, language options or extension cables.
For repair shops adding everyday electrical testing capabilities, or distributors exploring new workshop tools, this car circuit tester combines several useful functions in one kit.
Check Before You Order#
Does the DM109 support AC testing?
No. The DM109 supports DC testing only.
Can it test direct injection injectors?
No. Injector testing is intended for supported 12V port fuel injectors.
Are extension cables included?
The 5m and 10m extension cables are optional. Check the contents of your selected kit before ordering.
Can the firmware be upgraded?
The USB cable supports firmware upgrade connectivity. Upgrade availability and timing are subject to official confirmation.
How do I use the discount code?
Enter DM109UETJN45G at checkout. Confirm eligibility and the applied discount before completing payment. Ask Hanna if you need help.
Equip Your Workshop with the DM109#
Bring DC measurements, sensor voltage observation, 0–5V signal simulation and supported component tests together in a portable kit. Choose the package and extension cable that fit your work.
Use your DM109 discount code at checkout:
DM109UETJN45G
Pricing, availability, shipping and discount eligibility are shown on the product and checkout pages.
Need help with functions, language customization or bulk purchasing? Chat with Hanna on WhatsApp →
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