How to Use an OBD2 Scanner — Complete Beginner Guide
What Is an OBD2 Scanner?
An OBD2 (On-Board Diagnostics II) scanner is a device that plugs into your car's diagnostic port to read error codes stored by the vehicle's computer. Every car sold in the US since 1996 has an OBD2 port, usually located under the dashboard near the steering column.
Scanners range from $15 Bluetooth adapters that pair with your phone to $300+ professional-grade tools with live data streaming. For most DIY troubleshooting, a basic scanner works perfectly.
Step 1: Locate the OBD2 Port
The 16-pin OBD2 port is typically under the driver's side dashboard, within 2 feet of the steering column. Common locations:
- Most cars: Below and left of the steering wheel
- Some Toyota/Lexus: Behind a small panel below the dash
- Some BMW/Mercedes: In the center console or glove box area
Step 2: Connect the Scanner
Turn the ignition to the "ON" position (don't start the engine). Plug the scanner into the OBD2 port. The scanner should power on automatically — it draws power from the car's electrical system.
Step 3: Read the Codes
Select "Read Codes" or "Scan" from the menu. The scanner will communicate with your car's ECU and display any stored diagnostic trouble codes (DTCs). Write down all codes — there may be multiple.
Step 4: Understand the Codes
Each code follows a standard format: a letter followed by 4 digits (e.g., P0420). The first letter tells you the system:
- P = Powertrain (engine, transmission)
- B = Body (airbags, A/C, seat belts)
- C = Chassis (ABS, steering, suspension)
- U = Network (communication between modules)
Look up your specific code on FixCarCodes.com for detailed diagnosis and repair steps.
Step 5: Clear the Codes (Optional)
After making repairs, select "Clear Codes" or "Erase" to reset the check engine light. Drive for 50-100 miles to let the car's computer run its self-tests. If the problem is fixed, the light stays off. If not, it will return.
Recommended OBD2 Scanners
| Scanner | Price | Best For |
|---|---|---|
| BAFX Bluetooth OBD2 | ~$22 | Budget Android users |
| BlueDriver Pro | ~$100 | Detailed reports + fix suggestions |
| FIXD OBD2 Scanner | ~$60 | Beginners wanting plain-English explanations |
| Autel MaxiCOM MK808 | ~$300 | Professional-level diagnostics |
Frequently Asked Questions
Can I use an OBD2 scanner on any car?
Yes, all gasoline cars sold in the US since 1996 and diesel vehicles since 1997 support OBD2. Older vehicles use different protocols.
Will clearing codes fix my car?
No. Clearing codes only resets the check engine light. If the underlying problem isn't fixed, the code will return within a few drive cycles.
Can a scanner damage my car?
No. OBD2 scanners only read data — they can't modify your car's programming or cause any damage.