What does an OBD2 scanner do?
Types of OBD2 Scanners
- Basic scanners: These read the fault codes and give a short description of them. They are rather cheap and work perfectly for novices. These types of models are normally handheld, easy to handle, and usually come with a display screen.
- The advanced models: Unlike the basic scanners, these have more features incorporated. They can give live data, reset codes, and even perform advanced diagnostics, such as emission tests. Some can even show real-time data of your car's performance, like RPM, vehicle speed, and fuel trim.
- The Bluetooth OBD2 scanners: They connect with your smartphone or tablet. These scanners take help from apps to provide information. They are portable and have easy handling, and you can store data on your smartphone. You can analyze data for a period of time using an app and see what happens with your vehicle's performance.
How to Read OBD2 Fault Codes
- Connect the Scanner
- Turn on the Ignition
- Select Your Vehicle
- Scan for Fault Codes
- Analyze Displayed Fault Codes
Common Fault Codes Explanation
- P0171 indicates a lean fuel mixture in the engine, meaning it would receive less than the normal amount of fuel. The possible causes for this would be a leakage in the vacuum or a defective fuel pump.
- P0420 means the catalytic converter is malfunctioning. It could also be a sign that the converter is failing or that there is a problem with the oxygen sensors.
- P0455 indicates a major leak in the evaporative emission control system. It could be as minor as a loose gas cap.
How OBD2 Data Helps When Buying Used Cars
- First, scan the vehicle to see if there are any fault codes. If the seller says that everything's perfect and in great shape, well, those fault codes raise a flag. For example, if you see some codes about the engine or transmission, that might be bad news. Several codes may indicate something more serious is going on that may require attention.
- You can also use the advanced OBD2 scanners' live data feature. This will show you real-time information regarding your engine RPM, coolant temperature, and fuel trim levels. This allows you to make better estimates regarding the condition of the car. If the readings appear wrong, then that could indicate backing out of the sale.
- Coupled with the scanner, you should also run a VIN check to get the vehicle history report. This gives you critical information about the car's history. You can find out if the car was in any accidents, the current title status, actual mileage, maintenance records, and more.
Common Mistakes to Avoid When Using an OBD2 Scanner
- Don't ignore pending codes: There are some things that can go wrong in your car that don't trip the check engine light yet but will turn on a code in memory.
- Do not clear codes without attending to the issue. Once the codes are cleared while the fault is present, the check engine light will be back again, which could further damage your car.
- Do not depend on the scanner for diagnosis. While OBD2 scanners are a great way to gain insight, they don't fully understand the context of the fault or the repair history of the car. They are best used in conjunction with other diagnostic methodologies and visual inspections.


