Obdii Reader tools are essential for modern car diagnostics, providing real-time insights into your vehicle’s health. With the right scan tool, you can decode trouble codes, monitor performance data, and potentially save thousands on mechanic fees. CARDIAGTECH.NET offers a wide selection of OBD2 scanners to meet every need and budget. Understanding your car’s onboard diagnostic system allows you to stay ahead of potential problems.
1. Understanding the OBDII Reader: A Comprehensive Guide
An OBDII reader, also known as an OBD2 scanner or diagnostic scan tool, is an electronic device used to access and interpret data from a vehicle’s On-Board Diagnostics system. The “II” in OBDII refers to the second generation of this standardized system, which became mandatory in the United States for all cars and light trucks manufactured after 1996. This standardization ensures that any OBDII-compliant scan tool can communicate with any OBDII-compliant vehicle, regardless of make or model. The primary function of an OBDII reader is to retrieve Diagnostic Trouble Codes (DTCs) from the vehicle’s computer. These codes indicate specific problems within the car’s various systems, such as the engine, transmission, emissions controls, and more. By reading and interpreting these codes, mechanics and car owners alike can quickly identify the source of a problem and begin the repair process.
Beyond reading DTCs, advanced OBDII readers can also provide real-time data from the vehicle’s sensors, including engine speed (RPM), coolant temperature, oxygen sensor readings, and fuel trim levels. This data can be invaluable for diagnosing intermittent problems or monitoring the overall health of the engine. Some advanced scanners also offer bi-directional control, allowing users to command certain vehicle functions, such as turning on the cooling fans or cycling the ABS pump, for diagnostic purposes. OBDII readers are used by professional mechanics in auto repair shops, as well as by DIY car enthusiasts who want to save money on repairs and maintenance. They range in complexity from simple code readers that display DTCs to sophisticated scan tools with advanced graphing and data logging capabilities.
1.1. What is OBDII and Why is it Important?
OBDII stands for On-Board Diagnostics II, a standardized system implemented in vehicles to monitor engine performance, emissions, and other critical systems. The Society of Automotive Engineers (SAE) developed the initial standards, and the Environmental Protection Agency (EPA) mandated OBDII compliance in the United States for all cars and light trucks manufactured after January 1, 1996. Similar regulations exist in other countries as well. The primary purpose of OBDII is to ensure that vehicles meet strict emissions standards. The system monitors various components and sensors to detect any malfunctions that could increase emissions. When a problem is detected, the OBDII system stores a Diagnostic Trouble Code (DTC) in the vehicle’s computer and illuminates the “Check Engine” light on the dashboard.
The importance of OBDII lies in its ability to provide valuable diagnostic information to mechanics and car owners. By connecting an OBDII reader to the vehicle’s diagnostic port, users can retrieve DTCs and access real-time sensor data. This information can help pinpoint the source of a problem and guide the repair process. Additionally, OBDII data can be used to monitor the overall health of the engine and identify potential problems before they become major issues. OBDII has also played a significant role in reducing vehicle emissions. By detecting and alerting drivers to emissions-related problems, the system encourages timely repairs, which helps to keep vehicles running cleaner and more efficiently.
1.2. Key Components of an OBDII System
The OBDII system consists of several key components that work together to monitor and diagnose vehicle performance:
- Sensors: Various sensors throughout the vehicle monitor parameters such as engine speed, coolant temperature, oxygen levels, and airflow.
- Engine Control Unit (ECU): The ECU, also known as the powertrain control module (PCM), is the central computer that processes data from the sensors and controls various engine functions.
- Diagnostic Trouble Codes (DTCs): When a sensor reading falls outside of the acceptable range, the ECU stores a DTC, which is a standardized code that indicates the nature of the problem.
- Diagnostic Port: A standardized 16-pin connector, usually located under the dashboard, provides access to the OBDII system.
- OBDII Reader: A handheld device or software application that connects to the diagnostic port and allows users to retrieve DTCs and access real-time sensor data.
1.3. Benefits of Using an OBDII Reader
Using an OBDII reader offers numerous benefits for both professional mechanics and DIY car owners:
- Accurate Diagnostics: OBDII readers provide access to valuable diagnostic information, allowing users to accurately identify the source of a problem and avoid unnecessary repairs.
- Cost Savings: By diagnosing problems themselves, car owners can save money on diagnostic fees at the repair shop. They can also make informed decisions about repairs and avoid being overcharged.
- Preventative Maintenance: OBDII data can be used to monitor the overall health of the engine and identify potential problems before they become major issues. This can help prevent costly breakdowns and extend the life of the vehicle.
- Emissions Compliance: OBDII readers can be used to check if a vehicle is ready for emissions testing. This can help car owners avoid failing the test and incurring fines.
- Performance Monitoring: Advanced OBDII readers can provide real-time data on engine performance, allowing users to monitor parameters such as horsepower, torque, and fuel economy.
1.4. Common OBDII Terms and Definitions
Understanding common OBDII terms and definitions is essential for using an OBDII reader effectively:
| Term | Definition |
|---|---|
| DTC | Diagnostic Trouble Code – A standardized code that indicates a specific problem within the vehicle’s systems. |
| MIL | Malfunction Indicator Lamp – Commonly known as the “Check Engine” light. |
| PID | Parameter Identification – A code that identifies a specific data parameter, such as engine speed or coolant temperature. |
| Freeze Frame Data | A snapshot of sensor data taken when a DTC is stored. This data can provide valuable clues about the conditions that led to the problem. |
| Live Data | Real-time sensor data that is displayed while the engine is running. |
| Readiness Monitors | Tests performed by the OBDII system to ensure that various emissions-related components are functioning correctly. These monitors must be “ready” for emissions testing. |
| Scan Tool | Another term for an OBDII reader. |
An OBDII port for connecting your OBDII reader.
2. Types of OBDII Readers: Choosing the Right Tool
OBDII readers come in various forms, each with its own set of features and capabilities. The best type of scanner for you will depend on your specific needs and budget. Here’s an overview of the most common types of OBDII readers:
2.1. Basic Code Readers
Basic code readers are the simplest and most affordable type of OBDII scanner. These devices can read and clear Diagnostic Trouble Codes (DTCs) and display basic information about the code, such as its definition. They typically have a small screen and a few buttons for navigation. Basic code readers are ideal for DIY car owners who want to quickly diagnose common problems and reset the “Check Engine” light. However, they usually lack advanced features such as live data streaming, graphing, and bi-directional control.
2.2. Enhanced OBDII Scanners
Enhanced OBDII scanners offer more features and capabilities than basic code readers. In addition to reading and clearing DTCs, they can also display live sensor data, perform advanced diagnostic tests, and access manufacturer-specific codes. These scanners typically have a larger screen and more sophisticated software. Enhanced OBDII scanners are suitable for experienced DIYers and professional mechanics who need more in-depth diagnostic information.
2.3. Professional Scan Tools
Professional scan tools are the most advanced and expensive type of OBDII scanner. These tools offer a wide range of features, including bi-directional control, advanced graphing, data logging, and access to vehicle-specific repair information. They are typically used by professional mechanics in auto repair shops. Professional scan tools can perform complex diagnostic procedures and help mechanics quickly and accurately diagnose even the most challenging problems.
2.4. Smartphone OBDII Adapters
Smartphone OBDII adapters are small devices that plug into the vehicle’s diagnostic port and communicate with a smartphone or tablet via Bluetooth or Wi-Fi. These adapters work in conjunction with a mobile app that displays DTCs, live data, and other diagnostic information. Smartphone OBDII adapters are a popular choice for DIY car owners who want a portable and affordable scanning solution. They offer many of the same features as enhanced OBDII scanners, but at a lower price point.
2.5. PC-Based OBDII Scanners
PC-based OBDII scanners consist of a hardware interface that connects to the vehicle’s diagnostic port and software that runs on a laptop or desktop computer. These scanners offer a large screen and powerful processing capabilities, making them ideal for advanced diagnostics and data analysis. PC-based OBDII scanners are often used by professional mechanics and automotive engineers.
3. Top OBDII Reader Features: What to Look For
When choosing an OBDII reader, it’s important to consider the features that are most important to you. Here are some of the top features to look for:
3.1. DTC Reading and Clearing
The ability to read and clear Diagnostic Trouble Codes (DTCs) is the most basic and essential function of an OBDII reader. Make sure the scanner can read both generic OBDII codes and manufacturer-specific codes. The scanner should also be able to clear the codes and reset the “Check Engine” light after the problem has been resolved.
3.2. Live Data Streaming
Live data streaming allows you to view real-time sensor data from the vehicle’s engine and other systems. This data can be invaluable for diagnosing intermittent problems and monitoring the overall health of the engine. Look for a scanner that can display multiple data parameters simultaneously and has graphing capabilities.
3.3. Freeze Frame Data
Freeze frame data is a snapshot of sensor data taken when a DTC is stored. This data can provide valuable clues about the conditions that led to the problem. Look for a scanner that can display freeze frame data and allow you to analyze it.
3.4. O2 Sensor Testing
Oxygen (O2) sensors play a critical role in monitoring emissions and ensuring optimal engine performance. An OBDII reader with O2 sensor testing capabilities can help you diagnose problems with the O2 sensors and ensure that they are functioning correctly.
3.5. Readiness Testing
Readiness monitors are tests performed by the OBDII system to ensure that various emissions-related components are functioning correctly. An OBDII reader with readiness testing capabilities can help you determine if your vehicle is ready for emissions testing.
3.6. Bi-Directional Control
Bi-directional control allows you to command certain vehicle functions, such as turning on the cooling fans or cycling the ABS pump, for diagnostic purposes. This feature is typically found on professional scan tools and can be very useful for diagnosing complex problems.
3.7. Data Logging
Data logging allows you to record sensor data over a period of time and then analyze it later. This feature can be useful for diagnosing intermittent problems and identifying trends in engine performance.
3.8. Vehicle Coverage
Make sure the OBDII reader is compatible with your vehicle’s make and model. Some scanners are designed to work with specific vehicle brands, while others offer broader coverage.
3.9. Ease of Use
Choose an OBDII reader that is easy to use and has a clear, intuitive interface. The scanner should have a large screen and well-labeled buttons.
3.10. Software Updates
Make sure the OBDII reader can be updated with the latest software. Software updates can add new features, improve performance, and ensure compatibility with newer vehicles.
| Feature | Basic Code Reader | Enhanced OBDII Scanner | Professional Scan Tool | Smartphone Adapter | PC-Based Scanner |
|---|---|---|---|---|---|
| DTC Reading/Clearing | Yes | Yes | Yes | Yes | Yes |
| Live Data Streaming | No | Yes | Yes | Yes | Yes |
| Freeze Frame Data | No | Yes | Yes | Yes | Yes |
| O2 Sensor Testing | No | Yes | Yes | Yes | Yes |
| Readiness Testing | No | Yes | Yes | Yes | Yes |
| Bi-Directional Control | No | No | Yes | No | Yes |
| Data Logging | No | No | Yes | No | Yes |
| Vehicle Coverage | Limited | Broad | Broad | Broad | Broad |
| Ease of Use | High | Medium | Low | High | Medium |
| Software Updates | Limited | Regular | Regular | Regular | Regular |
| Price | Low | Medium | High | Low-Medium | Medium-High |
4. How to Use an OBDII Reader: A Step-by-Step Guide
Using an OBDII reader is a relatively simple process, but it’s important to follow the correct steps to ensure accurate results. Here’s a step-by-step guide:
4.1. Locating the OBDII Port
The OBDII port is typically located under the dashboard on the driver’s side of the vehicle. It is a standardized 16-pin connector. In some vehicles, the port may be hidden behind a small panel or cover. Refer to your vehicle’s owner’s manual if you are unable to locate the port.
4.2. Connecting the OBDII Reader
With the vehicle’s ignition turned off, plug the OBDII reader into the diagnostic port. Make sure the connector is fully seated and securely connected.
4.3. Turning on the Ignition
Turn the vehicle’s ignition to the “ON” position, but do not start the engine. This will provide power to the OBDII system and allow the scanner to communicate with the vehicle’s computer.
4.4. Navigating the Scanner Menu
Use the scanner’s buttons to navigate the menu and select the desired function. Typically, you will want to start by reading DTCs. Follow the on-screen prompts to retrieve the codes.
4.5. Interpreting the DTCs
The scanner will display any stored DTCs, along with a brief description of the code. Refer to a DTC code database or repair manual to get more detailed information about the code and its possible causes. Websites like CARDIAGTECH.NET offer extensive databases of OBDII codes and repair information.
4.6. Clearing the DTCs (Optional)
After you have diagnosed and repaired the problem, you can clear the DTCs and reset the “Check Engine” light. However, it’s important to note that clearing the codes will not fix the underlying problem. The “Check Engine” light will likely return if the problem is not resolved.
4.7. Monitoring Live Data (Optional)
If you want to monitor live sensor data, select the “Live Data” function on the scanner. Choose the data parameters you want to monitor and observe the readings while the engine is running. This can be useful for diagnosing intermittent problems and monitoring engine performance.
4.8. Disconnecting the OBDII Reader
After you have finished using the OBDII reader, turn off the ignition and disconnect the scanner from the diagnostic port. Store the scanner in a safe place.
Connect the OBDII reader to the OBDII port.
5. Common OBDII Codes and Their Meanings
OBDII codes are standardized across all vehicle makes and models, but the specific meaning of a code can vary depending on the vehicle. Here are some of the most common OBDII codes and their general meanings:
5.1. P0100-P0199: Mass Airflow (MAF) and Volume Airflow (VAF) Circuit Malfunctions
These codes indicate problems with the MAF or VAF sensor, which measures the amount of air entering the engine. A faulty MAF or VAF sensor can cause a variety of problems, including poor fuel economy, rough idling, and stalling.
5.2. P0300-P0399: Misfire Codes
Misfire codes indicate that one or more cylinders in the engine are not firing properly. Misfires can be caused by a variety of factors, including faulty spark plugs, ignition coils, fuel injectors, or vacuum leaks.
5.3. P0400-P0499: Exhaust Gas Recirculation (EGR) System Malfunctions
These codes indicate problems with the EGR system, which recirculates a portion of the exhaust gas back into the engine to reduce emissions. A faulty EGR valve or EGR system can cause poor engine performance and increased emissions.
5.4. P0420: Catalyst System Efficiency Below Threshold (Bank 1)
This code indicates that the catalytic converter is not functioning efficiently enough to reduce emissions. A faulty catalytic converter can cause the vehicle to fail an emissions test.
5.5. P0500-P0599: Vehicle Speed Sensor (VSS) Malfunctions
These codes indicate problems with the VSS, which measures the vehicle’s speed. A faulty VSS can cause problems with the speedometer, cruise control, and transmission shifting.
5.6. B Codes
Body codes (B codes) relate to components within the body of the vehicle. These can be things like your power windows, your air bags, your seats, etc.
5.7. C Codes
Chassis codes (C codes) deal with things like ABS, suspension, and steering.
5.8. U Codes
Network codes (U codes) deal with the communication systems that the other systems depend on. For example, if the computer cannot communicate with the ABS, you will see a U code.
| OBDII Code | Description | Possible Causes |
|---|---|---|
| P0101 | Mass Air Flow (MAF) Circuit Range/Performance Problem | Dirty or faulty MAF sensor, vacuum leak, faulty wiring |
| P0300 | Random/Multiple Cylinder Misfire Detected | Faulty spark plugs, ignition coils, fuel injectors, vacuum leak, low compression |
| P0401 | Exhaust Gas Recirculation (EGR) Flow Insufficient Detected | Faulty EGR valve, clogged EGR passages, vacuum leak |
| P0420 | Catalyst System Efficiency Below Threshold (Bank 1) | Faulty catalytic converter, exhaust leak, faulty O2 sensors |
| P0500 | Vehicle Speed Sensor (VSS) Malfunction | Faulty VSS, faulty wiring, faulty ABS system |
| B1000 | Control Module | Internal malfunction of the control module, wiring or connections fault, power or ground fault. |
| C0035 | Right Front Wheel Speed Sensor Circuit | Faulty wheel speed sensor, damaged sensor wiring, or issues within the ABS module itself. |
| U0100 | Lost Communication With ECM/PCM | Wiring issues, a faulty ECM/PCM, or problems with the CAN bus network. |
6. Advanced OBDII Diagnostics: Going Beyond the Basics
Once you’re comfortable with the basics of using an OBDII reader, you can start exploring some of the more advanced diagnostic techniques. Here are a few examples:
6.1. Graphing Live Data
Graphing live data can help you visualize changes in sensor readings over time. This can be particularly useful for diagnosing intermittent problems or identifying trends in engine performance. Look for an OBDII reader that has graphing capabilities and allows you to customize the graph display.
6.2. Performing Active Tests
Active tests, also known as bi-directional control tests, allow you to command certain vehicle functions using the OBDII reader. For example, you can turn on the cooling fans, cycle the ABS pump, or activate the fuel injectors. These tests can be very useful for diagnosing problems with specific components.
6.3. Accessing Manufacturer-Specific Codes
In addition to the standardized OBDII codes, many vehicle manufacturers also use their own proprietary codes. These codes can provide more detailed information about specific problems. To access manufacturer-specific codes, you will need an OBDII reader that supports the specific vehicle brand.
6.4. Using a Digital Multimeter
A digital multimeter (DMM) is an essential tool for electrical diagnostics. You can use a DMM to test the voltage, resistance, and continuity of various circuits and components. This can help you identify faulty wiring, sensors, and actuators.
6.5. Using a Scan Tool with Oscilloscope Functions
Some advanced scan tools include oscilloscope functions, which allow you to visualize electrical signals in real-time. This can be very useful for diagnosing complex electrical problems, such as those involving sensors, actuators, and communication networks.
7. OBDII Reader Maintenance and Care
To ensure that your OBDII reader continues to function properly, it’s important to perform regular maintenance and care. Here are a few tips:
- Keep the scanner clean and dry. Avoid exposing the scanner to moisture or extreme temperatures.
- Store the scanner in a safe place. When not in use, store the scanner in a protective case or drawer to prevent damage.
- Update the software regularly. Check for software updates on the manufacturer’s website and install them to ensure that the scanner has the latest features and vehicle coverage.
- Replace the batteries as needed. If the scanner uses batteries, replace them when they start to weaken.
- Handle the connector with care. Avoid bending or twisting the connector, as this can damage the pins.
8. Choosing the Right OBDII Reader for Your Needs
Selecting the right OBDII reader involves considering your budget, the types of vehicles you’ll be working on, and the diagnostic capabilities you require. Here’s a breakdown to help you decide:
8.1. For DIY Enthusiasts
If you’re a car owner looking to perform basic diagnostics and maintenance, a basic code reader or a smartphone OBDII adapter might suffice. These tools are affordable and easy to use, allowing you to read and clear codes, check engine lights, and access some live data.
8.2. For Experienced Mechanics
For more in-depth diagnostics, an enhanced OBDII scanner or a PC-based scanner would be more appropriate. These tools offer advanced features like live data streaming, freeze frame data, O2 sensor testing, and readiness testing.
8.3. For Professional Use
If you’re a professional mechanic working on a variety of vehicles, a professional scan tool is essential. These tools offer the most comprehensive features, including bi-directional control, data logging, manufacturer-specific codes, and access to repair information.
Consider your long-term needs as well. As technology evolves, having a scanner that can receive software updates is crucial. This ensures your tool remains compatible with newer vehicles and continues to provide accurate diagnostics. Websites like CARDIAGTECH.NET offer resources and support to help you make the right choice, including detailed product descriptions and customer reviews.
9. Where to Buy OBDII Readers
OBDII readers are available from a variety of sources, including:
- Auto Parts Stores: Many auto parts stores, such as AutoZone, Advance Auto Parts, and O’Reilly Auto Parts, sell a range of OBDII readers.
- Online Retailers: Online retailers, such as Amazon and eBay, offer a wide selection of OBDII readers at competitive prices.
- Specialty Tool Stores: Specialty tool stores, such as Snap-on and Mac Tools, sell professional-grade OBDII scan tools.
- Direct from Manufacturers: Some manufacturers sell their OBDII readers directly to consumers through their websites. Consider CARDIAGTECH.NET for a curated selection of high-quality OBDII readers.
When purchasing an OBDII reader, it’s important to buy from a reputable source and to read customer reviews before making a decision. Make sure the scanner comes with a warranty and that the seller offers technical support.
10. The Future of OBDII Technology
OBDII technology is constantly evolving to meet the changing needs of the automotive industry. Here are some of the trends shaping the future of OBDII:
- Increased Integration with Mobile Devices: Smartphone OBDII adapters are becoming increasingly popular, offering a convenient and affordable way to access diagnostic information.
- Cloud-Based Diagnostics: Cloud-based diagnostic platforms are emerging, allowing mechanics to access vehicle data and repair information remotely.
- Advanced Driver-Assistance Systems (ADAS) Integration: OBDII scanners are being integrated with ADAS systems, allowing mechanics to diagnose and calibrate these complex systems.
- Cybersecurity: As vehicles become more connected, cybersecurity is becoming an increasingly important concern. OBDII scanners are being developed with enhanced security features to protect against hacking.
11. Contact CARDIAGTECH.NET for Your OBDII Reader Needs
At CARDIAGTECH.NET, we understand the challenges you face in the automotive repair industry. The physical demands, constant need for updated knowledge, and pressure to deliver efficient and accurate service can be overwhelming. That’s why we offer a range of high-quality OBDII readers designed to help you work smarter, not harder.
Our tools are selected to enhance your efficiency, reduce repair times, and improve diagnostic accuracy. By choosing CARDIAGTECH.NET, you’re investing in your professional growth and the success of your business.
Don’t let outdated tools hold you back. Contact us today to discover how our OBDII readers can transform your approach to automotive diagnostics and repair. We’re here to help you succeed.
Contact Information
- Address: 276 Reock St, City of Orange, NJ 07050, United States
- WhatsApp: +1 (641) 206-8880
- Website: CARDIAGTECH.NET
12. Frequently Asked Questions (FAQs) about OBDII Readers
Here are some frequently asked questions about OBDII readers:
12.1. What is the difference between OBDII and OBD1?
OBD1 was the first generation of on-board diagnostics, used in vehicles before 1996. It lacked standardization, so each manufacturer had its own diagnostic connector and codes. OBDII is a standardized system that is used in all cars and light trucks manufactured after 1996.
12.2. Can an OBDII reader diagnose ABS and airbag problems?
Some advanced OBDII readers can diagnose ABS and airbag problems, but not all. You will need a scanner that supports these systems.
12.3. Can I use an OBDII reader to program keys or reset the immobilizer?
Some professional-grade OBDII scan tools can program keys and reset the immobilizer, but this is not a common feature.
12.4. How often should I use an OBDII reader to check my car?
You should use an OBDII reader whenever the “Check Engine” light comes on, or if you notice any unusual symptoms, such as poor fuel economy, rough idling, or stalling.
12.5. Can I use an OBDII reader to turn off the “Check Engine” light permanently?
Clearing the codes will turn off the “Check Engine” light, but if the underlying problem is not resolved, the light will come back on.
12.6. Are all OBDII readers compatible with all vehicles?
Most OBDII readers are compatible with all cars and light trucks manufactured after 1996, but it’s important to check the scanner’s vehicle coverage before purchasing.
12.7. Do I need to be a mechanic to use an OBDII reader?
No, you don’t need to be a mechanic to use an OBDII reader. Basic code readers are very easy to use, and there are many resources available online to help you interpret the codes.
12.8. Can I use an OBDII reader while driving?
It is not recommended to use an OBDII reader while driving, as it can be distracting.
12.9. How do I update the software on my OBDII reader?
Refer to the manufacturer’s instructions for updating the software on your OBDII reader. Typically, you will need to connect the scanner to a computer and download the latest software from the manufacturer’s website.
12.10. What should I do if my OBDII reader won’t connect to my car?
Check the following:
- Make sure the OBDII reader is securely connected to the diagnostic port.
- Make sure the vehicle’s ignition is turned to the “ON” position.
- Check the scanner’s vehicle coverage to make sure it is compatible with your car.
- Try a different OBDII reader to rule out a problem with the scanner.
- Consult a mechanic if you are unable to resolve the problem.
13. Conclusion: Empowering Your Automotive Diagnostics with an OBDII Reader
Investing in an OBDII reader is a smart decision for anyone who wants to take control of their car’s maintenance and repair. Whether you’re a DIY enthusiast or a professional mechanic, an OBDII reader can provide valuable diagnostic information that can save you time and money. By understanding the basics of OBDII technology, choosing the right scanner for your needs, and following proper maintenance procedures, you can empower yourself to diagnose and repair your car like a pro. Remember to explore the options available at CARDIAGTECH.NET to find the perfect OBDII reader for your specific requirements.
By equipping yourself with the right tools and knowledge, you can ensure that your vehicle stays in top condition and avoid costly repairs down the road. Don’t hesitate to contact CARDIAGTECH.NET for expert advice and support in choosing the best OBDII reader for your needs.
