The tool that tells you why the light came on. What you pay for is how deep into the car it can see.
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Our top pick in this category
1. Best all-system scanner
Autel MaxiCOM MK808S
Autel · score 9.0/10
A 7 in Android 11 tablet that reads and clears codes on all available systems and performs bi-directional active tests — the point where a scanner stops being a code reader.
A self-contained 7 in Android 11 tablet at 1024 x 600, running a Cortex-A55 quad-core with a 5000 mAh battery, that reads and clears codes on all available systems and performs bi-directional active tests. Autel lists oil reset, EPB, SAS, DPF, injector and battery registration among the service functions. This is where a scanner stops being a code reader and starts being a diagnostic tool. Far more capability than reading a check-engine light needs, and function coverage varies by make.
Photographs on this page are licensed stock images that show the category, not the exact model, and not anything we own. We have no test rig and claim none.
Every car sold in the US since 1996 has a standardized diagnostic socket, usually under the dash near the steering column. Plug a scanner into it and the car will tell you which fault codes it has stored. That is the baseline capability, it is legally mandated, and a twenty-dollar reader delivers it as well as a thousand-dollar tablet.
What more money buys is reach: access to systems beyond the engine, live sensor data at usable speed, and the ability to command a component rather than just read about it.
The four tiers, and who each one is for
OBD2 scanner capability tiers
Tier
What it does
Who it suits
Code reader
Reads and clears engine codes, emissions readiness, freeze frame
Anyone whose check-engine light just came on
Live-data reader
Adds graphed sensor data you can watch while driving
Chasing an intermittent fault
Enhanced / all-system
Adds ABS, airbag, transmission and other modules
Anyone doing their own brake or suspension work
Bidirectional
Commands components — cycles a pump, bleeds ABS, retracts a caliper
Electric parking brakes, ABS bleeding, real diagnosis
OBD2 scanner capability tiers
The step that matters most for a DIY owner is the third one. Modern brake work frequently needs the electronic parking brake retracted, and a plain code reader cannot do it. We separate the tiers by what manufacturers publish in bidirectional vs basic scanners, and scanner vs code reader settles the terminology, which the industry uses inconsistently.
Dongle and phone, or a self-contained tool
A Bluetooth dongle plus a phone app is cheap, small, and often more capable than a handheld at the same price — BlueDriver Pro reads enhanced ABS and airbag codes, and OBDLink's MX+ reaches Ford MS-CAN and GM SW-CAN networks that most adapters cannot see. The trade-off is that your diagnostic tool now depends on a charged phone, a working app and, on some tools, an account.
A self-contained handheld or tablet has its own screen and battery and works when your phone does not. It is also one more device to keep charged and updated. Neither answer is wrong; bluetooth vs wired scanners lays out the real differences.
Ask about updates before you buy
A scanner is software in a plastic case, and the software ages. Manufacturers handle this very differently: Innova states updates for the 5610 are free with no subscription, while other makers gate newer vehicle coverage or advanced functions behind a paid renewal. Neither model is dishonest, but a cheap tool with an expensive annual renewal can cost more over three years than a dearer one that never asks again.
Clearing a code is not fixing a fault
A scanner can turn the check-engine light off. That is a tempting button, and it is the wrong one to press first. The code is the car telling you what it noticed; clearing it erases the evidence and the light will return when the fault recurs — possibly after you have sold the car to someone else, and definitely before an emissions test, which also checks the readiness monitors that clearing resets. How to clear a check engine light covers the order of operations, and how to use an OBD2 scanner starts from plugging it in.
+−Does a cheap OBD2 scanner read ABS and airbag codes?
Usually not. Basic readers cover engine and emissions only — FOXWELL, for instance, does not publish ABS or SRS coverage for the NT301, so we treat it as engine and emissions. Reading ABS or airbag codes generally means an enhanced tool such as BlueDriver Pro or an all-system scanner.
+−Should the engine be running when I use a scanner?
Ignition on is enough to read stored codes. Live data needs the engine running, because the values you want to watch only exist when the engine is working. Read codes first, then decide whether you need live data.
+−Will a scanner work on any car?
Any OBD2-compliant vehicle, which in the US means 1996 and newer. Region matters too — Innova states the 5610 works only in the US and Canada. Older vehicles used manufacturer-specific systems that a generic OBD2 tool cannot read.
