What's the deal?

The Topdon TopScan Bluetooth OBD automotive scanne is on sale at Amazon for Black Friday, slashing 40% off the price, bringing it down to $54.

Also: The best Black Friday deals live now

ZDNET's key takeaways

• Packed with features that you'd expect from a high-end professional scan tool and gives the ability to carry out some deep-dive diagnostics.
  
• Software can be tricky to use, and some features require advanced knowledge to get their full benefit.

Few things are more annoying than the dreaded "check engine" light suddenly appearing on your car's dashboard. It's one of those things that means a trip to a mechanic, being without your car for a period, and big bills.

If you're at all technical and DIY-minded, tackling car repairs might not be outside of your skill set. Here's the problem: Cars are complicated things, and require computers to carry out diagnostics and repairs. Without one of these "car computers," you're not going to get far.

Well, this is the power that the Topdon TopScan Bluetooth OBD automotive scanne gives you. 

Topdon TopScan features

• Full system diagnostics
• Ability to read/clear trouble codes, access ECU (engine control unit) information, read vehicle VIN, view real-time data, and run active tests
• Run vehicle reset functions: Oil reset, throttle adaptation, EPB (electronic parking brake)  reset, steering angle reset, DPF (diesel particulate filter) regeneration, ABS (anti-lock braking system) bleeding, BMS (battery management system) reset, and airbag reset
• Bi-directional scan tool enables you to send commands from your smartphone directly to the vehicle's ECU for active testing and control features such as dashboard, windows, doors, sunroof, lights, etc.
• Supports 70+ different vehicle makes across American, Asian, and European markets
  
• Works with iOS and Android
• After the first year of free updates, the subscription fee for the second year is $49.99/year for all applicable vehicle models and all features 

If you've used those cheap OBD scan tools in the past, then prepare to be blown away by what the TopScan can do. While it's easy to find a cheap and cheerful scan tool for reading and clearing codes, and some that will handle more advanced tasks, the TopScan bests them all, allowing you to do seriously advanced diagnostics and repair tasks, such as injector coding, sunroof initialization, door lock tests, and dashboard diagnostics.

Plug the tool into the vehicle's OBD port -- finding this can be a bit of a challenge at times, and an internet search is often needed -- fire up the app, and away you go!

And if all this sounds complicated, fear not, because you get access to Topdon's repair data library, This is a comprehensive knowledge base and a fantastic tool for those who want to save money and solve minor vehicle problems. 

ZDNET's buying advice

The Topdon TopSca is the best smartphone-based OBD automotive diagnostic tool I've ever used. The wealth of features that it provides access to is amazing -- and all for $90. 

An incredible value!

As with most things, using something like this comes with a learning curve, because nothing can transform you into a mechanic overnight, but with this tool in your toolbox, you'll be able to tackle some serious car troubleshooting jobs.