Product Reviews

Topdon OBII Scanner Review

A cheap, easy way to read & clear codes on your car

Have a check engine light (CEL)?

Do you get them often?

One option is to go to a local store like Pep Boys or Autozone and get them to scan your car for free and tell you all of the faults. That works well if you only have an occasional CEL or live really close to a car parts store.

But technology has changed, and OBII scanners have gone from something only mechanics could afford to something anyone with $30 and an Amazon account can easily pick up.

I was recently approached by the team at Topdon Technologies to try out their new Topdon OBD2 scanner that retails for just under $30 and is super easy to use. It’s meant for the consumer market rather than mechanics, and in the month I’ve owned it it’s already proven well worth the price of admission. Full disclosure, they gave me one for free to review on my site, but this did not influence my review.

You can pick it up on Amazon here:

How to Use It

Operation is super simple. Unbox the device and plug it into your OBD2 port, typically located underneath your steering wheel and slightly offset to the left (in the US, anyway). Turn the ignition to the “ON” location, but don’t start the engine.

The Topdon scanner will automatically turn on and show you four options – engine scan (OBD2), ready test (for emissions), Setup, and About. For most cases, you’ll want to do the engine scan which will tell you what is causing the check engine light to appear, then give you a chance to clear the code and see if it comes back.

OBD2 Scan / Check Engine Light

If you have a CEL, choose the first option and run the scan. It will come back with a specific error code (typically 3 digits) and a brief message explaining the issue. You can then go to Google and type in that specific 3-4 digit fault code, plus the corresponding message. I’d also suggest adding your vehicle make and model, i.e. Toyota Camry P0420 Code – Catalyst System Efficiency Below Threshold.

Typically you’ll find results of plenty of other people explaining in more laymen’s terms what the problem is, how severe it is, and how to fix it.

Most commonly, if it’s an intermittent fault, you can just clear the code and see if it comes back…especially if it’s something related to emissions or misfire, as it could be something as simple as a bad tank of gas or dumb luck. If the issue is persistent it’s time to go get the car checked.

Emissions Ready Status

If you’ve failed your Emissions or SMOG test, or anticipate that you might, then this tool is equally handy as it will give you a heads up if the emissions testing center will see any codes or issues when they scan your vehicle, and allow you to clear them. Most places require you drive 20 miles before it can be scanned, so don’t do this immediately before the test otherwise they can tell. Regardless, this will save you a lot of headaches if you have a car that struggles with emissions, as you can make sure you’ll pass at home before spending the money to have it professionally tested and declined.

Other Features

The product can also do real time monitoring, check your VIN to make sure it matches when evaluating buying a used car, and a handful of other operations.

On the flipside, it can’t do things like custom coding of the ECU to over-ride factory settings, for that you’ll need a VAG-com cable (of equivalent if you don’t have an Audi/VW) that is quite a bit more expensive.

Testing it in Action

In my case, I got the aforementioned CEL due to code P0420 which my TopDon scanner quickly revealed. I Googled the error and found several helpful articles explaining it means there is something wrong with the exhaust system, typically an O2 sensor malfunction, which could be anything from bad gas to an O2 sensor failure, so I cleared the code to see if it would come back.

I drove around for a few days and it didn’t return right away, but did pop back up one more time. Again I scanned the codes using my TopDon scanner, saw it was the same issue, and tried clearing it one more time before taking it to a mechanic. It easily cleared as before, and several weeks later it has yet to come back, saving me an expensive trip to a mechanic only for them not being able to recreate the issue.

While it’s not always a good idea to clear and ignore error codes, using Google and common sense can help you decide if the CEL is due to a serious issue (i.e. misfiring engine) or a minor issue (emissions related) that can be ignored for a few days.

In my case I knew that a faulty O2 sensor, the most likely culprit, wasn’t likely to cause any long-term damage to the car, so it was an acceptable risk for me to clear it and see if it would come back. I had also recently filled my gas tank, so I had a hunch it was due to bad gas.

Who Should Buy It?

This product is ideal for anyone who either has a problematic car, buys and sells cars often, or simply wants to have enough tools in their garage to diagnose and fix most common problems with their vehicles. OBD2 ports are found in nearly every new vehicle, so it doesn’t really matter what you drive now or in the future as long as it’s made in the last few decades.

For $30 it’s a smart investment and you’ll thank yourself the first time you used it. As mentioned earlier I got a CEL in my Toyota Camry daily driver which was related to the O2 sensors malfunctioning, and I cleared it immediately. It came back a few days later, I cleared it again, and I haven’t had an issue since (it’s been about a month).

Because the device is small, I plan to keep mine in the glove box so that if my car ever breaks down or throws a CEL, I can immediately pull over and determine the cause. This will be especially good on road trips to know how safe it is to proceed or not, and when to call a tow truck.

A big thank you to TopDon technology for letting me try their product. If you want to pick one up, follow this link:

Nick Roshon

Nick has been an Audi owner and fanatic for the last 10 years, and started Nick's Car Blog in 2009 to share DIYs and pictures of his A4. Currently he drives a 2012 Audi TT-RS, and has previously owned a B7 S4, B7 A4, and an 82 Audi Coupe (GT) LeMons race car. In his day job, Nick is a digital marketer and lives in San Diego, CA, USA.

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