Order before 16:00 on business days? Shipped the same day!

Fast & reliable shipping throughout Europe

Expert customer service with professional advice

Mega Sale: Discounts up to 75%! While supplies last!

View Offers
Discover similar products: Circuit testers, TopDiag
Topdiag  |  SKU: B0180

TopDiag P200 | Circuit Tester

€144,95 incl.
€119,79 excl.

Warranty directly via AsTools

We handle warranty cases ourselves, quickly and without involving the manufacturer. Thanks to our own parts inventory and technical expertise, we can usually assist you immediately. Only in exceptional cases do we still send the product to the supplier.

2 years warranty on all products

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

Easy returns

You can easily request your return through your account. We will send you the return label by email. Return shipping costs are your responsibility.

Professional customer service

Our experts are ready to help you quickly and professionally, both online and in our physical store. Questions? Feel free to contact us!

The TopDiag P200 circuit tester is engineered for comprehensive electrical vehicle diagnostics, combining the capabilities of a multimeter, oscilloscope, and component tester in a single device. The tester is compatible with both 12V and 24V vehicle systems with an operating voltage range of 9V to 30V and can measure up to 100V. The unit is powered directly via the included battery clamps or a cigarette lighter adapter, allowing you to test electrical circuits throughout the vehicle using the extended test lead and removable test probes. This tool is specifically designed for tracing wiring, identifying short circuits, and checking sensors and actuators in modern automotive systems.

In practical use, the tester operates with Smart Test technology, where the device automatically detects whether voltage (VDC) or resistance (Ohm) is being measured based on the connected probe. When determining polarity, a red or green LED indicator and an audible signal immediately show whether you're dealing with positive or negative power. Additionally, the tool features a built-in power supply that allows you to actively control components such as lights, fuel injectors, and relays in multiple test modes (Moment, Latch, Pulse). During operation, an adjustable electronic circuit breaker ranging from 1A to 18A protects the vehicle circuit from overload, which is essential for safely diagnosing components without external power supplies or separate fuses.

KEY FEATURES

✔Adjustable circuit breaker from 1A to 18A — Prevents sensitive wiring from melting when powering suspect or shorted circuits.
✔Smart Test technology — Automatically recognizes whether voltage or resistance is being measured, eliminating the need to manually switch between modes during quick checks.
✔Control components in three modes — Powers lights, injectors, and relays directly through the test probe in Moment, Latch, and Pulse settings.
✔Oscilloscope, relay test, and injector test built-in — Functions that typically require separate tools on comparable circuit testers.

IMPORTANT LIMITATIONS

✕Not suitable for control modules and communication lines — Applying power directly to ECUs or airbag modules will cause irreversible damage to the electronics.
✕Operating voltage from 9V to 30V — High-voltage systems in hybrid and electric vehicles are outside the scope.
✕Vehicle power supply — The device does not operate independently; an external power source is required if the battery is flat.
✕Operating temperature from 0°C to 60°C — Not designed for work below freezing outside the workshop.

Application and functionality

This circuit tester offers a range of measurement and testing functions for targeted diagnostics of vehicle electronics.

  • Smart Test: Automatic detection of the measured quantity—voltage or resistance—on the test probe. This eliminates the need to manually switch between measurement modes during quick checks.
  • Multimeter mode: Full functionality for measuring DC voltage, resistance, continuity, diodes, current in amperes, and frequency in hertz for detailed circuit diagnostics.
  • Component activation: Direct power supply to actuators such as cooling fans, starter motors, or lights with 12V or 24V via the test probe, with operating modes Moment, Latch, and Pulse for specific test procedures.
  • Battery test for 12V and 24V: Analyzes the condition of the vehicle battery without connecting external equipment. Performs charge tests, start tests, and load tests to check battery capacity and charging system operation.

Advanced features and capabilities

For in-depth fault finding, the system is equipped with various advanced test functions.

  • Oscilloscope mode: Provides a visual display of electrical signals with a voltage range of 1V to 49V to analyze pulsating signals from sensors and network communication such as PWM.
  • Relay test: A dedicated test interface for checking standard 4-pin and 5-pin automotive relays, including visual wiring diagrams on the built-in display.
  • Injector test: Sends specific pulse signals to fuel injectors to check mechanical and electrical operation, allowing you to rule out blockages or faulty coils.
  • Adjustable circuit breaker: The internal short-circuit protection can be manually set between 1A and 18A. This prevents sensitive wiring from melting when powering suspect or short-circuited circuits.

Package contents

  • 1x TopDiag P200 circuit tester
  • 1x Solid copper/stainless steel test probe
  • 1x Set of battery clamps, red and black
  • 1x Cigarette lighter adapter
  • 1x Main cable with extension cable
  • 1x Relay Test Cable Set
  • 1x Extra Ground Cable with Clamp
💡
Good to know: Never use component activation or direct power/ground supply on communication lines or control modules such as ECUs or SRS and airbag modules. Applying voltage directly to these sensitive components can cause irreversible damage to the electronics. Always consult the vehicle's wiring diagram if you're unsure.

Technical specifications

General

The brand that manufactures the tester.Brand
TopDiag
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 helps locate the position of a short circuit or broken wire, saving considerable searching.Short circuit and wire break detection
The tester automatically detects whether a point carries positive, earth or nothing. Useful for quick work.Automatic test
Checks whether a wire or connection conducts current.Continuity 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
The tester can also check the condition of the battery.Battery test

Display and controls

The number of pixels on the screen. More pixels give a sharper image.Screen resolution
320 x 240 pixels
The tester gives a beep or tone, so you do not need to keep looking at the screen.Audible signal

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 temperatures at which you can use the tester, for instance in a cold workshop.Operating temperature
0 to 60 °C
The temperatures at which you can safely store the tester.Storage temperature
-40 to 70 °C

Other specifications

Display
320x240 DPI TFT Color Display
Power Supply
12V or 24V, powered via vehicle battery
Resistance Measurement Range
1 ohm - 200K ohm
Oscilloscope Voltage Range
1V - 49V
Circuit Breaker Protection
Adjustable from 1A to 18A