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Autool  |  SKU: BT280

Autool BT280 | Circuit Tester

€149,95 incl.
€99,95 incl.
€82,60 excl.

Warranty directly via AsTools

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2 years warranty on all products

All our products come with a 2-year factory warranty. This ensures you long-lasting quality and service.

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The Autool BT280 circuit tester is designed to perform comprehensive electrical diagnostics on 12V and 24V vehicle electrical systems. The tester operates at a working voltage of 9V to 30V and measures DC voltage up to 100V with its robust measurement sensor. The device is powered directly from the vehicle battery via the supplied battery clamps and a 6-meter power cable. This generous cable length allows the diagnostic technician to perform measurements around the entire vehicle without extension cords, from fuse boxes in the engine bay to lighting circuits at the rear of a commercial vehicle or trailer.

During troubleshooting, the tester automatically detects the circuit type via the Smart Test mode, after which current measurement values for voltage and resistance appear directly on the 2.4-inch color LCD display screen. Beyond passive measurement, the device offers the ability to actively test actuators such as cooling fans, windshield wiper motors, or lights by applying power or ground directly to a component via a button. The built-in red and green LED indicators provide instant visual confirmation of the detected polarity. Thanks to the integrated work light, the measurement location is always well illuminated, which significantly simplifies tracing wiring in dark and confined spaces.

KEY FEATURES

✔Adjustable 0–5V power simulation — Simulates sensor outputs such as a MAP or throttle position sensor to test the wiring to the ECU and its response.
✔Configurable overload protection — The trip current can be adjusted in the menu, protecting the tester, wiring, and component when actively applying voltage.
✔Injector and relay testing built-in — Four pulse modes for injectors and a separate test port for 4- and 5-pin relays, without engine ECU intervention.
✔6-meter power cable — Measure around the entire vehicle without extension cords, from the fuse box to the rear lights of a trailer.

IMPORTANT NOTES

✕Never apply system voltage to 5V circuits — Applying 12V or 24V directly to a sensor circuit or CAN bus will permanently damage the ECU; use only the 0–5V simulation mode for this.
✕Power simulation limited to 100 mA — Intended for signal simulation, not for powering loads through this output.
✕System voltage from 9V to 30V — High-voltage systems in hybrid and electric vehicles are outside the scope of this tester.
✕Powered by the vehicle battery — The device cannot operate independently; an external power source is required if the battery is depleted.

Applications and functionality

This circuit tester consolidates multiple diagnostic tools by combining standard measurement instruments with active testing capabilities.

  • Multimeter mode: Measures fundamental electrical parameters, including DC voltage from 0.1V to 100V, resistance from 1Ω to 200 kΩ, current up to 18A, and frequency. Also includes a diode test for checking semiconductors in charging circuits or relay diodes.
  • Oscilloscope mode: Generates a graphical display of measured voltage over time. Essential for monitoring dynamic signals such as PWM control signals and sensor outputs, or detecting voltage drops on the data bus.
  • Smart Test: An automated mode that independently detects whether the probe is touching positive, ground, or resistance. The tester automatically switches to the correct measurement unit, significantly speeding up troubleshooting.
  • Component activation: Delivers available battery voltage or ground directly to an actuator or load to verify operation. The activation mode can be set to momentary (while the button is pressed), continuous (locked), or via a repeating pulse signal.

Special features and capabilities

For comprehensive diagnostics of modern engine management systems, the tester includes specialized simulation and protection functions.

  • Injector test: Features four dedicated pulse modes for controlling fuel injectors. Allows safe testing of the injector inside or outside the vehicle for proper mechanical opening, closing, and spray pattern, without involving the engine ECU.
  • Relay diagnostics: Via a dedicated test port and included adapter cables, common 4- and 5-pin automotive relays can be directly activated and tested for proper contact closure.
  • 0–5V power simulation: Generates an adjustable reference voltage between 0V and 5V, limited to a safe output current of 100 mA. This function is used to simulate sensor outputs such as a MAP sensor or throttle position sensor, to test wiring and ECU response.
  • Adjustable overload protection: Features an electronic current breaker with a configurable trip current in the menu. This protects the tester, vehicle wiring, and the tested component against short circuits and excessive current draw during active power delivery.

Package contents

  • 1x Autool BT280 circuit tester
  • 1x 6-meter power cable with battery clamps and extension connector
  • 1x Test cable set for relay diagnostics, with clamps
  • 1x Set of interchangeable test probes and sensors
  • 1x Extra ground cable with clamp, green and black
  • 1x USB cable for firmware updates
  • 1x Rugged storage case
  • 1x User Manual
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Good to know: Always exercise extreme caution when using the component activation function. Consult the wiring diagram before applying voltage to any unfamiliar wire. Directly applying 12V or 24V to a 5V sensor circuit or communication line such as the CAN-bus will permanently damage the engine control unit or sensors. For 5V circuits, use only the built-in 0–5V simulation mode.

Technical specifications

General

The brand that manufactures the tester.Brand
Autool
What type of device it is. A circuit tester checks current and earth; a wire tracer locates cables and short circuits.Type of tester
Circuit tester
The on-board voltage the tester can connect to. For testing lorries as well, 24 V or higher is required.Suitable for system voltage
9 to 30 V
Where the tester draws its power from. Via the vehicle battery or circuit, there is no need to replace batteries.Power supply
Via vehicle battery

Measuring

The voltage range in which the tester measures accurately. A wider range is useful for heavier vehicles.DC voltage measuring range
0.1 to 100 V
The resistance values the tester can measure, for instance of sensors or wires.Resistance measuring range
0 to 200 kΩ
Whether the tester can display a signal as a graph. This reveals faults a standard measurement may miss.Oscilloscope

Test functions

The tester can supply current to components such as a motor or lamp, so you can see whether they work.Component activation
The tester automatically detects whether a point carries positive, earth or nothing. Useful for quick work.Automatic test
Shows whether a connection is positive or negative.Polarity check
Checks whether a diode conducts current in one direction only.Diode test
The tester can pulse injectors to check whether they operate correctly.Injector test
Checks whether a relay switches correctly.Relay test

Display and controls

The screen size, measured corner to corner. A larger screen is easier to read.Screen diagonal
2.4 inch
The tester gives a beep or tone, so you do not need to keep looking at the screen.Audible signal
A built-in light to help you see what you are doing in dark areas.Work light

Protection

Which faults the tester protects itself and the vehicle against. This prevents damage from incorrect connection.Protections
  • Overcurrent
  • Short circuit

Dimensions and weight

The length of the test cable. A long cable also allows you to reach the rear of a vehicle.Cable length
6 m

Other specifications

Resistance Range
1Ω - 200 KΩ
Current Range
0 - 18A
Power Supply Simulation
0V - 5V, maximum 100 mA output
Display
2.4-inch HD LCD color screen
Additional Features
Built-in work light and acoustic buzzer