Is a Bidirectional OBD2 Scanner Worth It for DIY? (2026)

Last updated 21 October 2026. Prices and ratings checked on Amazon UK that day.

Yes, but only if you will do jobs that need it. A bidirectional OBD2 scanner is worth it for DIY if you do your own electronic parking brake (EPB) service, DPF regeneration, ABS bleeding, battery registration or actuator tests to find a faulty component. If you only read and clear check-engine codes, a basic code reader is enough.

We compared seven scanners listed on Amazon UK from £33.98 to £539.00 on 21 October 2026, from an engine-only code reader to Autel tablets, to show where the extra money goes.

Quick verdict: buy a basic code reader such as the TOPDON AL400 (£33.98) if you only need engine codes. Move to a bidirectional scanner such as the TOPDON TopScan Master (£135.94) or XTOOL A30M kit (£199.99) if you do your own brakes, servicing or diagnosis and want service resets and active tests. The Autel MK808S (£417.04) and MK900 (£539.00) are tablet-style tools for people working on many different cars. Check the update terms before you buy, because several listings include only one year of free updates.

Jump to: Quick picks · Scanner vs code reader · What bidirectional does · Jobs that need it · Subscription and update costs · Who should buy one · Models to consider · How we compiled this shortlist · FAQs

Quick picks: bidirectional OBD2 scanners on Amazon UK

These labels describe what each listing says the tool does. See how we compiled this shortlist for the method.

• Engine-only code reader, lowest price: TOPDON AL400 (£33.98)
• Lowest-priced bidirectional tool here (small rating sample): GOOLOO DS200 (£59.99)
• Bidirectional with 30+ resets, one year of free updates: TOPDON TopScan Master (£135.94)
• Bidirectional kit with case and extension cable, lifetime free updates: XTOOL A30M kit (£199.99)
• Full-system scan tool with 9 services, no bidirectional control listed: TOPDON ArtiDiag600 Pro (£219.00)
• Autel tablet with 3,000+ active tests: Autel MaxiCOM MK808S (£417.04)
• Autel tablet with 40+ services and an 8-inch screen: Autel MaxiCOM MK900 (£539.00)

Bidirectional OBD2 scanners compared

Functions, coverage and update terms are manufacturer or seller claims taken from each Amazon UK listing; vehicle coverage differs by make and model, so check your car before buying. The GOOLOO DS200 (37 ratings) has a small rating sample. The two Autel listings are long-running pages, and Amazon ratings on those can include reviews of earlier versions of a product.

Bidirectional scanner vs basic code reader: what is the difference?

A code reader reads and clears fault codes and shows basic data from the engine. The TOPDON AL400 listing is an example: it describes reading and erasing codes, I/M readiness, freeze frame data and live data, and says it is a basic scanner that can check engine faults but not faults in other systems.

A scan tool goes further. The scan tools here list access to other control modules such as ABS, airbag, transmission, body control and air conditioning, plus service functions such as oil reset and electronic parking brake (EPB) reset. A bidirectional scan tool adds one more ability: it sends commands to the car instead of only listening. That is the feature this guide is about.

What does a bidirectional OBD2 scanner actually do?

With a one-way reader, the scanner receives information from the car’s computers. With bidirectional control (also called active tests or actuator tests), the scanner can also ask a component to do something: switch a fan on, cycle the air conditioning clutch, run a fuel pump or open a sunroof. The Autel MK808S listing describes this as outputting commands to the control units and monitoring how the actuators respond, so you can tell whether a fault lies in the wiring, a relay or the component itself without removing parts.

Used properly, that can shorten a diagnosis. It also means the tool can make parts of the car move or run, so follow the vehicle maker’s procedure, keep hands, tools and loose clothing clear, and stop if you are not sure what the test will do.

Which DIY jobs need a bidirectional OBD2 scanner?

The listings here name these functions, and several are bidirectional or service-mode jobs rather than plain code reading:

• Electronic parking brake (EPB) reset: named on the GOOLOO DS200, XTOOL A30M and Autel MK808S listings; the TopScan Master and MK900 describe it only in descriptive text, so check the listing for your car. Many cars with an electric parking brake need the rear brake motors put into a service mode before the pads can be changed. Check your car’s service manual for the exact procedure.
• DPF regeneration: listed on the TopScan Master, A30M and ArtiDiag600 Pro, among others. Whether a forced regeneration is appropriate for your car is a question for the handbook or a garage, because it depends on the cause of the blockage and conditions such as fuel level and temperature.
• ABS brake bleeding: named on the A30M, ArtiDiag600 Pro and MK808S listings (the MK900 lists “brake bleed”). Some cars need the ABS pump cycled during a brake fluid change to remove air.
• Battery registration: listed on the A30M, MK808S and others (the ArtiDiag600 Pro calls it battery matching). Some cars expect to be told when a new battery has been fitted.
• Throttle relearn, steering angle sensor calibration and injector coding: named on several listings.
• Actuator tests: fuel pump, injectors, air conditioning clutch, cooling fan and similar, to check a component before you buy a part.

If none of those apply to the work you do, you may never use bidirectional control. This guide does not cover disabling or removing emissions equipment; these tools are sold for diagnosis and servicing.

Subscription and update costs

The scanner is only part of the cost, because several tools include a limited period of free software updates. The terms on each listing differ:

• TOPDON TopScan Master: one year of free updates, then monthly, quarterly or yearly renewal. The listing says the core functions (full-system read and clear codes and live data) remain usable without renewal. It says FCA secure gateway access is a paid add-on that is not included.
• GOOLOO DS200: a Q&A answer on the listing says the first year is free, then plans are priced in US dollars per month, quarter or year. Check the current price in pounds before you buy.
• XTOOL A30M kit: the listing says lifetime free updates and no subscription required.
• TOPDON ArtiDiag600 Pro: the listing says lifetime free updates.
• Autel MK808S and MK900: one year of free updates; the listings say that after that, offline features continue to work (MK808S) or most features remain active (MK900). Both listings are sold by Autel Top and read as seller-written, so confirm the terms with Autel as well.

The listings do not define “lifetime”, and the ArtiDiag600 Pro’s Amazon specification table shows guaranteed software updates as unknown, so ask the seller or maker for the terms. Newer cars are where updates matter most: a tool that stops updating may stop covering models released after its last update.

When a bidirectional scanner is not worth it

• You only read and clear check-engine codes.
• The function you need is not named in the listing, or the listing does not cover your make and model.
• You need one job once, and a garage quote for that job is lower than the tool price.

Who should buy a bidirectional scanner?

• You only read check-engine codes: a code reader such as the TOPDON AL400 is enough, and you are not paying for features you will not use.
• You change your own brake pads or do your own servicing: a tool with EPB, oil and battery functions can save a garage visit. Compare the price of the tool with a quote for the specific jobs you expect to do on your car.
• You diagnose faults on a cheap used car: bidirectional control helps most if you regularly chase intermittent faults. The DS200 is the cheapest, but it has 37 ratings and paid updates after the first year; the TopScan Master and A30M have higher ratings than the DS200, though from around 100 ratings each, and are the entry points for full-system access with active tests.
• You work on several different makes, or for friends and family: the Autel MK808S and MK900 list the widest coverage here (150+ brands), but vehicle coverage varies by model and function, so check your cars before buying.

Do the job-by-job sum before you spend a few hundred pounds. Get quotes for the specific jobs you expect to need, add them up over the years you will keep the car, and compare the total with the tool price. If you only need one of them once, a scanner is unlikely to pay for itself.

Models to consider

TOPDON AL400: the engine-only code reader

Price: £33.98  |  Amazon rating: 4.3 from 2,191 ratings

The AL400 is the baseline in this guide. The listing describes a handheld reader with a 2.4-inch screen that reads and erases codes, shows I/M readiness (a check often used before an emissions test), freeze frame and live data. It says it works with the KWP2000, ISO9141, J1850 and CAN protocols, and that it checks engine faults but no other systems. The listing also contains two different vehicle-year statements: the title says after 2003, while a bullet says EU vehicles after 2000, so check your car’s year before you order.

Check the TOPDON AL400 on Amazon UK

GOOLOO DS200: lowest-priced bidirectional tool here

Price: £59.99  |  Amazon rating: 3.9 from 37 ratings

The DS200 is the cheapest tool here that lists bidirectional control. The listing describes sending commands from a smartphone to the car for tests including the A/C clutch, windows and sunroof, covering the engine, transmission, airbag, ABS, ESP, TPMS and immobiliser systems, with 8 maintenance services such as oil reset, throttle adaptation and EPB reset. It connects over Bluetooth 5.0 within 10 metres to an Android or iOS phone. The rating is the lowest here and based on only 37 ratings, and a Q&A answer says the first year of updates is free before paid plans apply.

Check the GOOLOO DS200 on Amazon UK

TOPDON TopScan Master: bidirectional with 30+ resets

Price: £135.94  |  Amazon rating: 4.3 from 101 ratings

The TopScan Master is a wireless scanner that works with a phone. The listing describes bidirectional control to test components such as windows, headlights, injectors and fuel pumps, full-system access, 30+ resets including oil and DPF resets, coverage for 120+ brands, and CAN-FD and DoIP support for newer cars. It also lists an AI assistant that interprets fault codes. The update terms are the main thing to read: one year free, then renewal, with core functions usable without renewal and FCA secure gateway access sold separately.

Check the TOPDON TopScan Master on Amazon UK

XTOOL A30M kit: bidirectional with lifetime free updates

Price: £199.99  |  Amazon rating: 4.5 from 98 ratings

The A30M kit is the highest-rated of the phone-based bidirectional tools here (4.5 from 98 ratings). The listing describes full bidirectional control for tests such as the fuel pump, injectors, A/C clutch and sunroof, 26 maintenance services including oil, EPB, DPF/GPF regeneration, ABS brake bleeding and battery reset, graphing of up to 8 data parameters at once, and CAN FD support. The kit adds a storage case and an OBD2 extension cable, the title says lifetime free updates, and a bullet says no subscription is required.

Check the XTOOL A30M kit on Amazon UK

TOPDON ArtiDiag600 Pro: full-system scan with 9 services

Price: £219.00  |  Amazon rating: 4.6 from 55 ratings

The ArtiDiag600 Pro is the best-rated tool here, but with only 55 ratings. It is a handheld tool with a 5-inch touchscreen rather than a phone-based one, and includes a lithium-ion battery. The listing describes diagnostics across the engine, transmission, ABS, body control and airbag systems, 9 maintenance functions (ABS bleeding, battery matching, brake reset, oil reset, DPF regeneration, throttle relearn, injector coding, SAS reset and TPMS reset), live data for up to four parameters, FCA AutoAuth and CAN-FD, and lifetime free updates. It does not describe active tests or bidirectional control, so it suits someone who wants service resets and full-system codes, not component commands.

Check the TOPDON ArtiDiag600 Pro on Amazon UK

Autel MaxiCOM MK808S: tablet with 3,000+ active tests

Price: £417.04  |  Amazon rating: 4.5 from 690 ratings

The MK808S has the most ratings of any bidirectional tool here. The listing describes a 7-inch Android 11 tablet with bidirectional control and 3,000+ active tests, 28+ reset services, all-system scanning, AutoVIN and AutoScan, and FCA secure gateway support. The title says 200+ brands while a bullet says 150+, so check your own car. It includes one year of free updates, after which the listing says offline features continue. The listing is sold by Autel Top, which describes itself as an Autel-certified seller, and the text reads as seller-written rather than from Autel. A customer review dated April 2023 on the page shows it is a long-running listing.

Check the Autel MaxiCOM MK808S on Amazon UK

Autel MaxiCOM MK900: tablet with 40+ services

Price: £539.00  |  Amazon rating: 4.4 from 581 ratings

The MK900 is the most expensive tool here. The listing describes an 8-inch Android 11 tablet with 64GB of memory, 40+ services, 3,000+ active tests, 150+ brands, CAN-FD and DoIP, and Wi-Fi printing. The main bullets give one year of free updates (a later description block says 24 months, so confirm with the seller), and the listing says most features remain active after the update subscription expires. The listing says it is the same as the MK900BT, but a customer review on the page disputes that, so treat the claim as unverified. The page shows it is sold by Autel Top and the text reads as seller-written, so check the specification with Autel. Choose it over the MK808S only if you want the larger screen and extra services.

Check the Autel MaxiCOM MK900 on Amazon UK

How we compiled this shortlist

All product details in this guide come from Amazon UK listings and manufacturer claims on those pages, checked on 21 October 2026, apart from the general buying and safety advice. TOPDON, GOOLOO, XTOOL and Autel are used descriptively.

We started with Amazon UK, where most British buyers will shop, and searched for bidirectional OBD2 scanners and for the Autel and Launch ranges. We chose seven tools to cover the range from an engine-only code reader to a tablet-style tool, with a mix of brands and update terms. We left out brand-specific tools (for a single make), heavy-duty truck tools, accessories and unbranded listings with few ratings. The Launch range was searched but is not included here. We compared each listing’s stated functions, the update terms, and the customer rating and number of ratings shown at the time.

Ratings move over time, and the number of ratings matters: the AL400 (2,191) has the most and the GOOLOO DS200 (37) the fewest. Prices were accurate on 21 October 2026 and change frequently, so use the links to see the current price. We will update this guide when prices, ratings or availability change.

Bidirectional OBD2 scanner FAQs

What is a bidirectional scanner?

It means the scanner can send commands to the car as well as read data from it. For example, it can turn on a fan or run a fuel pump so you can check whether the component works.

Is a bidirectional scanner worth it for a home mechanic?

Only if you will use it. It is worth considering if you do your own brake, battery or DPF-related work, or you chase faults on a car regularly. If you only read check-engine codes, a basic code reader is cheaper and enough.

Do I need a bidirectional scanner to change brake pads?

Not on every car. Cars with an electronic parking brake often need the rear brake motors put into service mode, which usually needs a scan tool with an EPB function. Check your car’s service manual.

What is the difference between a code reader and a bidirectional scanner?

A code reader mostly reads and clears fault codes and shows engine data. A bidirectional scanner can also send commands to components such as a fan, fuel pump or A/C clutch, and the ones here also list service resets such as oil, EPB and battery registration.

What is the cheapest bidirectional OBD2 scanner on Amazon UK?

Among the seven listings compared on 21 October 2026, the GOOLOO DS200 at £59.99 was the cheapest that lists bidirectional control. It has only 37 ratings, so read the listing carefully.

Can a bidirectional scanner do ABS bleeding?

Several listings here name ABS brake bleeding, including the XTOOL A30M, TOPDON ArtiDiag600 Pro and Autel MK808S. Coverage depends on the car, so check your make and model.

Do bidirectional scanners need a subscription?

It depends on the model. In this shortlist, the XTOOL A30M and TOPDON ArtiDiag600 Pro list lifetime free updates, while the TopScan Master, MK808S and MK900 list one year of free updates and the GOOLOO DS200 lists a first free year. Check what stops working when the free period ends.

Can I use a bidirectional scanner to disable emissions systems?

This guide does not cover that. These tools are sold for diagnosis and servicing, and removing or disabling emissions equipment on a road car is a legal and MOT question you should check before doing anything.

Is a bidirectional OBD2 scanner worth it for DIY?

It is worth it if you do jobs that need service resets or active tests, and not worth it if all you need is to read a check-engine light. For code reading only, the TOPDON AL400 (£33.98) is enough. For service functions and active tests on a budget, the GOOLOO DS200 (£59.99) is the cheapest but has a small rating sample; the TOPDON TopScan Master (£135.94) and XTOOL A30M kit (£199.99) have higher ratings, though from around 100 ratings each, and the A30M lists lifetime free updates. If you want service resets without bidirectional control, look at the TOPDON ArtiDiag600 Pro (£219.00). The Autel MK808S (£417.04) and MK900 (£539.00) suit people working on many different cars. Check your car’s coverage, the update terms and what is included before you order.

Affiliate disclosure: The Motoring World may earn a commission if you buy through links to Amazon UK, at no extra cost to you. We link to Amazon UK because most readers shop there; prices may differ elsewhere.

Prices, ratings and specifications were taken from Amazon UK listings on 21 October 2026 and may have changed.