Autel MS300 OBD2 Scanner Code Reader — Compact Plug-and-Play, Read/Clear Check Engine Codes & Emission Readiness

The Autel MS300 is a compact plug-and-play OBD2 code reader that reads and clears check engine codes, displays DTC definitions, and checks emission readiness.

Small enough to keep in your glovebox, the Autel MS300 connects to your vehicle’s 16-pin OBD2 port to retrieve generic and manufacturer-specific Diagnostic Trouble Codes (DTCs) and show on-screen definitions. It’s powered directly by the car, requires no batteries, and includes lookup software so you can interpret codes quickly. Designed for do-it-yourselfers and drivers who want faster answers before visiting a shop, the MS300 simplifies basic fault diagnosis and emission monitor checks.

How quickly does the MS300 give diagnostic information?

The MS300 communicates with the car’s onboard computer and returns codes in seconds, letting you identify trouble areas immediately. It shows code definitions on the device screen and includes lookup software on CD for deeper explanation.

• Instant readout of pending and stored DTCs
• On-screen DTC definitions for fast interpretation
• Included CD with code-definition database for offline reference
• No batteries — draws power from the vehicle’s OBD2 port

Can the MS300 turn off a check engine light?

Yes — once codes are read and the underlying issue is addressed, the MS300 can clear Diagnostic Trouble Codes and reset the MIL (Malfunction Indicator Lamp). Clearing codes helps determine if a temporary fault was the cause, such as a loose gas cap, before paying for repairs.

• Read and erase stored and pending codes
• Reset the check engine light after repair or confirmation
• Useful for confirming intermittent faults aren’t persistent
• Simple two-step operation: read then clear

Will the MS300 help my car pass a smog or emissions test?

The MS300 retrieves I/M Readiness monitor status so you can check whether emission-related systems (misfire, fuel system, catalyst, O2 sensors, EVAP, etc.) report as “ready.” That helps you gauge whether the vehicle is likely to pass an annual smog check or if additional drive cycles or repairs are needed first.

• Displays I/M Readiness status for emission monitors
• Identifies which monitors are ready or incomplete
• Helps avoid failed tests by pinpointing incomplete systems
• Supports standard OBDII protocols used in smog testing

Which vehicles are compatible with the Autel MS300?

The MS300 supports all OBD2 protocols — including CAN, ISO, KWP2000 and J1850 variants — and works with the vast majority of OBD-II compliant passenger cars and light trucks. Typical compatibility windows are post-1996 for the U.S., post-2006 for many European vehicles, and post-2009 for many Asian-market models.

• Compatible with 99% of OBD-II compliant vehicles
• Supports KWP2000, ISO9141, J1850 VPW/PWM, CAN, and more
• Simple 16-pin OBD2 connection — plug in and power on
• Includes 12-month warranty and lifetime technical support

Who is this for? The Autel MS300 is built for car owners, weekend mechanics, and fleet drivers who want fast, accurate fault codes without the complexity of full scan tools. It’s ideal if you want to diagnose check engine lights yourself, verify emission readiness before inspections, or avoid unnecessary shop charges. Technically straightforward and rugged, the MS300 belongs in any driver’s basic tool kit when you want quick answers and a simple way to clear codes after repairs.