FIRSTOOL V390 OBD2 Scanner — OBDII Diagnostic Code Reader with I/M Readiness & 12V Battery Test

FIRSTOOL V390 is a compact OBD2 diagnostic scanner that reads and clears engine fault codes, checks I/M readiness and tests 12V batteries for vehicles built after 1996.

The FIRSTOOL V390 gives drivers and mechanics a fast, straightforward way to diagnose common automotive problems without guesswork. Plug it into your vehicle’s OBDII port to retrieve generic and manufacturer-specific codes, view live sensor data, run emissions readiness checks and evaluate battery voltage. Its built-in code database and clear on-screen definitions help you understand issues so you can decide whether to DIY the repair or seek professional service.

How does the V390 identify and explain trouble codes?

The V390 scans for stored, pending and permanent Diagnostic Trouble Codes (DTCs) and displays plain-language definitions from an integrated database of over 40,000 faults. You can read code details on the unit and use the device to clear codes once repairs are completed, which also resets the Malfunction Indicator Light (MIL) when appropriate.

• Reads generic and manufacturer-specific DTCs
• Shows freeze-frame data to capture the conditions when a code set
• Built-in 40,000+ code definitions for immediate reference
• Clears codes and turns off the check engine light after fixing faults

Can the scanner help me prepare for an emissions (SMOG) test?

The V390 includes an I/M readiness check that inspects the status of emission system monitors to determine whether your vehicle is ready for inspection. Running this check before the test can save time and money by identifying which monitors are incomplete or failing so you can address issues first.

• Performs one-click I/M readiness status checks for OBDII-compliant vehicles
• Identifies incomplete or failed emissions monitors that may cause test failure
• Supports common OBDII protocols used in cars made after 1996
• Helps you avoid unexpected SMOG test rejections

What live data and tests can I read with this tool?

Beyond codes, the V390 streams real-time sensor information so you can watch RPM, coolant temperature, fuel trims and other key parameters while the engine runs. It also offers specific checks like EVAP leak testing and a battery voltage test to help pinpoint non-code issues.

• Real-time display of RPM, coolant temperature, vehicle speed and airflow
• Oxygen sensor testing and EVAP leak test capabilities
• 12V battery voltage monitoring to assess battery health quickly
• VIN/CIN retrieval and freeze-frame data for detailed diagnostics

Is the V390 compatible with my vehicle and easy to use?

The V390 works with most OBDII/CAN 16-pin vehicles: U.S. cars from 1996, EU models from 2003, and many Asian vehicles. It’s compact, durable and designed for plug-and-play use—no software downloads or batteries required—making it suitable for DIYers and professionals alike.

• Supports J1850PWM, J1850VPW, ISO9141, KWP2000 and CAN protocols
• Works with passenger cars, SUVs and light trucks using the OBDII standard
• Small, impact-resistant housing and a simple 5-key interface
• Multi-language menus including English, Spanish, French, German and more

Who is this for? The FIRSTOOL V390 is ideal for vehicle owners who want clear, actionable diagnostic information without expensive shop visits, as well as for technicians who need a reliable, portable code reader for routine diagnostics. It’s especially useful if you regularly monitor emissions readiness, perform basic troubleshooting, or want to check battery health quickly before long trips or inspections.