Autel Maxiscan MS300 OBD-II Code Reader

One thing that I brought back home was an Autel Maxiscan MS300 OBD-II Code Reader that is used to read diagnostic trouble codes from cars. My father’s aging 2000 Toyota Echo had its check engine light on and bringing it to a mechanic to read the code costs >$70, so we decided to try an inexpensive code reader instead and at around $20 on Amazon, the Autel reader fit the bill. This post contains some pictures of the code reader and how well or not well it worked for us.

Autel Maxiscan MS300
The Autel Maxiscan MS300 OBD reader with manual and CD

The Autel Maxiscan MS300 came with a manual and a CD with a diagnostic trouble code library. The MS300 is a simple device with an attached OBD (OnBoard Diagnostics) connector, a two line display and only two buttons: Enter and Scroll. It’s not nearly as fancy as the code readers used by professional mechanics, but the MS300 can read codes, the Vehicle ID number (VIN), and other information. Most importantly for us, the MS300 can clear the trouble codes and thus turn off the check engine light.

After receiving the MS300 in the mail, I first tried the device on my 2006 Mercedes ML350. My car didn’t have any problems at the moment, but I wanted to check the other functions of the reader. The MS300 is powered by the OBD port, and thus the device turns on once it’s plugged into the port.

MS300 Power On
MS300 when first plugged into the OBD port

To use the device, I have turn my car’s ignition to the “ON” position without starting the engine. After that, I pressed the “Enter” button on the MS300 and it started to scan for information. Once the scan is done, the reader told me how many error codes were there (0 in my case) and displays the menu as shown below.

MS300 Main Menu
MS300 Main Menu

There are five items in the menu: DTC Code, Erase, I/M Status, VIN, and Rescan. DTC Code displays any trouble codes in the car’s computer; erase clears the trouble codes and turns off the check engine light; I/M Status displays some inspection/emissions info; VIN reads the vehicles’s ID number; and rescan gets the reader to scan for information again. I tried the I/M and VIN functions on my car and both worked.

MS300 I/M Status
One of the screens under the I/M Status menu item.

I brought the reader back home in winter vacation and used it on my father’s 2000 Toyota Echo which had the check engine light on. The MS300 worked as well on the Echo and read the error codes. We know what the error code was and cleared it using the MS300. Hopefully the check engine light doesn’t come back any time soon, but if it does at least we have some idea of what the problem is before my dad has to fix the car. Overall, the Maxiscan MS300 worked as advertised and was easy to use, and that in my eyes makes it a decent purchase.

5 thoughts to “Autel Maxiscan MS300 OBD-II Code Reader”

  1. hi ihave the Ms300 and it erased my codes and turned off the check egine. However like it says in the manual, when you erase the codes it set I/m staus to off. so all the I/M’s are off except Fuel Ready CCM ready and missfire ready……the rest are set on off. But the manual does not say how to turn the I/M’s back on…….

      1. Well it does but that’s ok….lol lol After hours and hours of searching on the net for the ansewer……I decided to re-read the manual 2 times….lol lolIn fact, when you erase the codes all the I/M status will be marked not ready or incomplet accept three. The “fuel ready”, CCM will remain on and the miss-fire will remain on. These three are continuously monitored. All the rest are only monitored periodically.
        Those I/M stats will turn themselves on after driving the car a while, the onboard computer will test them and then they will have a ready status again And often after the car as been off for all night too.
        Thanks for taking the time to answer me and now you know about the I/M’s and how they turn back on……..

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