• Park safely with the transmission in Park (automatic) or Neutral (manual) and apply the parking brake.
• Turn key to ON/ACC (dashboard lights on) unless your scanner instructs otherwise.
• Locate the OBD‑II port—usually under the steering column within ~18 inches.
1) Plug the scanner into the OBD‑II port.
2) Turn the key to ON (engine off) or start the engine if prompted.
3) Choose “Read Codes” or “Diagnostics” from the menu.
4) Record all codes (e.g., P0420, P0301) including “pending” and “permanent.”
5) View Freeze Frame if available to capture sensor states at the fault moment.
Many parts retailers will read codes at no charge. Ask for a printout or photo of the exact code list. Then enter them here on ezOBD2 to see causes and fixes.
Pair a quality Bluetooth adapter with a reputable app. Follow in‑app steps to connect, then read/record codes. Ensure the app supports your vehicle modules if you need ABS/SRS beyond powertrain.
• Toyota/Honda/Nissan: Under dash, driver side.
• Ford/GM/Chrysler: Under dash near steering column; sometimes near fuse panel.
• VW/Audi/BMW: Lower dash by driver’s footwell; occasionally behind a small cover.
• Dead OBD port (blown fuse): Check the cigarette lighter/OBD fuse if the scanner won’t power.
• Reading only “current” codes: Always check pending and permanent too.
• Clearing codes early: This resets readiness monitors and can delay inspection readiness.
• Enter your code above or visit the OBD‑II Codes Index.
• Learn fundamentals in the OBD‑II Beginner’s Guide.
• If you need a tool, see How to Choose an OBD‑II Scanner.
Engine ON or OFF? Start with key ON, engine OFF. Some tests require engine ON—follow tool prompts.
Why no communication? Check fuses, try engine ON, verify adapter seating, and ensure ignition position is correct.
Is one code equal to one failed part? Not always. Use data and diagnostics to avoid parts‑swapping.
