What Are The Best OBD2 Scanners For A 1999 E46?

The best OBD2 scanners for a 1999 E46 are those that offer comprehensive diagnostic capabilities, real-time data monitoring, and user-friendly interfaces, ensuring effective vehicle maintenance and troubleshooting, and you can find all of these scanners at OBD2-SCANNER.EDU.VN. Choosing the right OBD2 scanner can significantly enhance your ability to diagnose and address automotive issues effectively.

1. Understanding OBD2 and the 1999 E46

OBD2, or On-Board Diagnostics II, is a standardized system used in most vehicles since 1996 to monitor engine performance and emissions. For the 1999 BMW E46, understanding OBD2 functionality is crucial for diagnosing and resolving various issues. Let’s delve deeper into what OBD2 entails and how it specifically applies to the 1999 E46.

1.1 What is OBD2?

OBD2 is a diagnostic system implemented in vehicles to monitor various parameters of the engine and related systems. It provides a standardized way to access vehicle health information, enabling mechanics and car owners to diagnose problems accurately. According to the Environmental Protection Agency (EPA), OBD2 systems are designed to ensure vehicles meet emissions standards and to alert drivers to potential issues.

1.2 OBD2 Ports in the 1999 E46

The 1999 E46, equipped with the M52TU engine, presents unique considerations regarding OBD2 port access. Unlike later E46 models, the 1999 version may have both an under-dash OBD2 port and a round connector under the hood. According to BMW forums, some early E46 models have known issues with the under-dash port’s ability to provide real-time data.

1.3 Common Issues with OBD2 Connectivity

Several factors can affect OBD2 connectivity in the 1999 E46:

• DME (Digital Motor Electronics) Bugs: Some early E46 models have software bugs in the DME that prevent proper connection with OBD2 scanners.
• Port Compatibility: Not all OBD2 scanners are fully compatible with the under-dash port, especially for reading real-time data.
• Connector Type: The presence of both the under-dash OBD2 port and the under-hood connector can cause confusion about which port to use.

1.4 Importance of Real-Time Data

Real-time data is essential for diagnosing many engine-related issues. It allows you to monitor parameters such as:

• Engine temperature
• O2 sensor readings
• Fuel trim levels
• Engine load

According to a study by the National Institute for Automotive Service Excellence (ASE), real-time data monitoring can reduce diagnostic time by up to 40%.

1.5 Using INPA and DIS Tools

For older BMW models like the 1999 E46, specialized BMW diagnostic tools such as INPA (Integrated Diagnostic Program) and DIS (Diagnostic Information System) can provide more in-depth diagnostics. These tools can often access real-time data and perform advanced functions that generic OBD2 scanners cannot. Research from BMW technical forums indicates that INPA, in particular, can sometimes read real-time data from the under-hood connector, even when standard OBD2 scanners fail.

2. Key Features to Look For in an OBD2 Scanner

When selecting an OBD2 scanner for your 1999 E46, several key features can ensure effective diagnostics and usability. These features range from basic code reading to advanced data analysis, catering to both novice users and experienced technicians.

2.1 Compatibility with BMW E46

The first and most crucial feature is ensuring the scanner is compatible with the 1999 BMW E46. Many generic OBD2 scanners claim compatibility, but it’s essential to verify that the scanner can read real-time data from your specific engine (M52TU). According to user reports on E46 forums, some scanners only read basic codes and not live data.

2.2 Real-Time Data Monitoring

Real-time data monitoring is vital for diagnosing complex issues. The scanner should display live data streams for parameters like:

• Engine RPM
• Coolant temperature
• O2 sensor readings
• Fuel trim

This feature allows you to observe how the engine behaves under different conditions, helping you pinpoint the source of the problem.

2.3 ABS and SRS Diagnostics

Beyond engine diagnostics, a good OBD2 scanner should also support ABS (Anti-lock Braking System) and SRS (Supplemental Restraint System) diagnostics. These systems are critical for safety, and being able to read and clear codes from these modules is highly beneficial.

2.4 User-Friendly Interface

A user-friendly interface is essential, especially for those new to OBD2 scanning. The scanner should have:

• A clear display
• Intuitive menus
• Easy navigation

Some scanners also offer smartphone integration, allowing you to view data on a larger screen and take advantage of additional features.

2.5 Wireless Connectivity (Bluetooth or Wi-Fi)

Wireless connectivity allows you to connect the scanner to your smartphone or tablet, providing more flexibility and convenience. With wireless connectivity, you can:

• View data remotely
• Record and share diagnostic information
• Update the scanner’s software

2.6 Software Updates

Regular software updates are crucial to ensure the scanner remains compatible with new vehicles and diagnostic protocols. A scanner with free or affordable update options is a significant advantage.

2.7 Code Definitions and Database

A comprehensive code database is essential for quickly understanding the meaning of diagnostic trouble codes (DTCs). The scanner should provide detailed descriptions of each code, helping you understand the potential causes and solutions.

2.8 Data Logging and Playback

Data logging allows you to record real-time data over a period, which can be invaluable for diagnosing intermittent issues. The ability to play back the recorded data helps you analyze the data more thoroughly.

2.9 Bi-Directional Control

Bi-directional control allows you to send commands to the vehicle’s computer to test various components. This feature is particularly useful for:

• Activating solenoids
• Testing sensors
• Performing calibrations

According to a study by the Society of Automotive Engineers (SAE), bi-directional control can significantly reduce diagnostic time and improve accuracy.

2.10 Multilingual Support

If you are more comfortable using a language other than English, a scanner with multilingual support can be beneficial. This feature ensures you can navigate the scanner’s menus and understand code definitions in your preferred language.

3. Top OBD2 Scanners for the 1999 E46

Based on compatibility, features, and user reviews, here are some of the top OBD2 scanners that are well-suited for the 1999 BMW E46:

3.1 Innova 3160g Diagnostic Scan Tool

The Innova 3160g is a popular choice for BMW owners due to its comprehensive diagnostic capabilities and user-friendly interface.

• Compatibility: Compatible with OBD2 protocols, including those used in the 1999 E46.
• Features:
  • Reads and clears ABS and SRS codes
  • Displays real-time data
  • Offers code definitions and a comprehensive database
• Pros:
  • Easy to use
  • Affordable
  • Reliable
• Cons:
  • May not support advanced bi-directional controls

3.2 Autel MaxiCOM MK808

The Autel MaxiCOM MK808 is a more advanced scanner that offers a wide range of features, making it suitable for both DIY enthusiasts and professional mechanics.

• Compatibility: Extensive vehicle coverage, including the 1999 E46.
• Features:
  • Full system diagnostics
  • Bi-directional control
  • Service functions (e.g., oil reset, EPB reset)
  • Software updates
• Pros:
  • Comprehensive diagnostics
  • User-friendly touchscreen interface
  • Regular software updates
• Cons:
  • Higher price point

3.3 Carly for BMW

Carly for BMW is a unique solution that uses a smartphone app and a compatible OBD2 adapter to diagnose and customize your BMW.

• Compatibility: Specifically designed for BMW vehicles, including the E46.
• Features:
  • Reads and clears fault codes
  • Displays real-time data
  • Allows coding and customization of vehicle settings
  • Performs service resets
• Pros:
  • BMW-specific diagnostics
  • Coding capabilities
  • Convenient smartphone app
• Cons:
  • Requires a subscription for full functionality
  • Adapter must be purchased separately

3.4 Foxwell NT510 Elite

The Foxwell NT510 Elite is another excellent option that offers in-depth diagnostics for BMW vehicles.

• Compatibility: BMW-specific diagnostics, including the 1999 E46.
• Features:
  • Full system scanning
  • Bi-directional control
  • Service functions
  • Software updates
• Pros:
  • Affordable
  • Comprehensive diagnostics
  • Easy to update
• Cons:
  • Interface may not be as intuitive as some other scanners

3.5 Launch Creader VIII

The Launch Creader VIII is a versatile OBD2 scanner that offers broad vehicle coverage and a range of features suitable for diagnosing the 1999 E46.

• Compatibility: Supports OBD2 protocols for a wide range of vehicles, including BMW.
• Features:
  • Reads and clears codes for multiple systems (engine, transmission, ABS, SRS)
  • Displays real-time data streams
  • Performs service resets (e.g., oil reset, brake reset)
  • Offers code definitions and troubleshooting tips
• Pros:
  • Affordable
  • Easy to use
  • Supports multiple systems
• Cons:
  • May not offer advanced bi-directional controls
  • Software updates may require a subscription

3.6 iCarsoft i910 BMW OBD2 Scanner Diagnostic Tool

The iCarsoft i910 is an older model, but still a powerful tool for diagnosing BMW vehicles, especially the E46.

• Compatibility: Specifically designed for BMW vehicles, including the E46.
• Features:
  • Reads and clears fault codes
  • Displays real-time data
  • Performs service resets
  • Supports various BMW systems
• Pros:
  • BMW-specific diagnostics
  • Easy to use
  • Affordable
• Cons:
  • Older model, so software updates may be limited
  • Screen resolution may be lower compared to newer models

3.7 Actron CP9690 Elite AutoScanner Kit

The Actron CP9690 Elite AutoScanner Kit is a comprehensive diagnostic tool that is compatible with a wide range of vehicles, including the 1999 BMW E46.

• Compatibility: Compatible with OBD2 protocols, including those used in the 1999 E46.
• Features:
  • Reads and clears ABS and SRS codes
  • Displays real-time data
  • Offers code definitions and a comprehensive database
  • Performs system tests
• Pros:
  • Easy to use
  • Affordable
  • Reliable
• Cons:
  • May not support advanced bi-directional controls

4. Step-by-Step Guide to Using an OBD2 Scanner on a 1999 E46

Using an OBD2 scanner on your 1999 E46 is a straightforward process. Here’s a step-by-step guide to help you get started:

4.1 Preparing for the Scan

1. Locate the OBD2 Port: On the 1999 E46, the OBD2 port is typically located under the dashboard on the driver’s side. Some models may also have a round connector under the hood.
2. Turn Off the Engine: Ensure the engine is turned off before plugging in the scanner.
3. Gather Information: Have your vehicle’s manual and any relevant repair information handy.

4.2 Connecting the Scanner

1. Plug in the Scanner: Insert the OBD2 scanner into the port. Ensure it is securely connected.
2. Turn on the Ignition: Turn the ignition to the “ON” position without starting the engine. This provides power to the scanner and the vehicle’s computer.

4.3 Reading Diagnostic Trouble Codes (DTCs)

1. Navigate the Scanner Menu: Use the scanner’s menu to select the “Read Codes” or “Diagnostic Codes” option.
2. Wait for the Scan: The scanner will communicate with the vehicle’s computer and retrieve any stored DTCs.
3. Record the Codes: Write down each DTC that appears on the scanner’s display.

4.4 Interpreting the Codes

1. Consult the Scanner’s Database: Use the scanner’s built-in database to look up the meaning of each DTC.
2. Research Further: If the scanner’s description is unclear, consult your vehicle’s manual or online resources for more information.

4.5 Clearing the Codes (Optional)

1. Select the “Clear Codes” Option: If you want to clear the DTCs, navigate to the “Clear Codes” or “Erase Codes” option in the scanner’s menu.
2. Confirm the Action: Follow the scanner’s prompts to confirm that you want to clear the codes.
3. Verify the Clear: After clearing the codes, start the engine and see if any codes reappear. If they do, the underlying issue still needs to be addressed.

4.6 Reading Real-Time Data

1. Select the “Live Data” Option: Navigate to the “Live Data” or “Real-Time Data” option in the scanner’s menu.
2. Choose Parameters: Select the parameters you want to monitor (e.g., engine RPM, coolant temperature, O2 sensor readings).
3. Monitor the Data: Observe the data streams as the engine runs. Look for any abnormal readings or fluctuations.

4.7 Using BMW-Specific Tools (INPA/DIS)

1. Install the Software: Install the INPA or DIS software on a compatible laptop.
2. Connect the Interface: Connect the BMW-specific diagnostic interface to the vehicle’s OBD2 port or under-hood connector.
3. Run the Software: Launch the INPA or DIS software and follow the prompts to connect to the vehicle.
4. Perform Diagnostics: Use the software’s menus to read codes, view real-time data, and perform advanced functions.

4.8 Tips for Accurate Diagnosis

• Verify the Codes: Always verify the DTCs with a second scan to ensure accuracy.
• Check for TSBs: Look for Technical Service Bulletins (TSBs) related to the DTCs. TSBs often provide detailed diagnostic and repair procedures.
• Address Multiple Codes: If multiple DTCs are present, address the most critical codes first, as they may be causing other issues.
• Document Your Work: Keep a record of the DTCs, diagnostic steps, and repairs you perform. This can be helpful for future reference.

4.9 Example Scenario

Let’s say your OBD2 scanner returns a code P0170, indicating a fuel trim malfunction.

1. Check the Fuel System: Inspect the fuel injectors, fuel filter, and fuel pump for any signs of damage or clogs.
2. Check the Air Intake System: Look for air leaks in the intake manifold or vacuum lines.
3. Check the O2 Sensors: Monitor the O2 sensor readings in real-time to see if they are functioning correctly.

By following these steps, you can effectively use an OBD2 scanner to diagnose and resolve issues on your 1999 BMW E46.

5. Common OBD2 Codes and Their Meanings for the 1999 E46

Understanding common OBD2 codes is essential for diagnosing issues in your 1999 E46. Here’s a list of frequently encountered codes and their possible causes:

5.1 P0170 – Fuel Trim Malfunction (Bank 1)

• Meaning: The engine’s air/fuel mixture is either too rich or too lean.
• Possible Causes:
  • Vacuum leak
  • Faulty O2 sensor
  • Dirty or faulty fuel injectors
  • Mass airflow (MAF) sensor issue
• Troubleshooting Steps:
  1. Inspect vacuum lines for leaks.
  2. Check O2 sensor readings.
  3. Clean or replace fuel injectors.
  4. Test or replace the MAF sensor.

5.2 P0300 – Random/Multiple Cylinder Misfire Detected

• Meaning: The engine is experiencing misfires in multiple cylinders.
• Possible Causes:
  • Faulty spark plugs
  • Faulty ignition coils
  • Vacuum leak
  • Low fuel pressure
• Troubleshooting Steps:
  1. Replace spark plugs.
  2. Test and replace ignition coils.
  3. Inspect vacuum lines for leaks.
  4. Check fuel pressure.

5.3 P0128 – Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

• Meaning: The engine coolant temperature is not reaching the required level.
• Possible Causes:
  • Faulty thermostat
  • Faulty coolant temperature sensor
• Troubleshooting Steps:
  1. Replace the thermostat.
  2. Check and replace the coolant temperature sensor.

5.4 P1421 – Secondary Air System Bank 1

• Meaning: Issue with the secondary air injection system.
• Possible Causes:
  • Faulty air pump
  • Leaking vacuum lines
  • Faulty valve
• Troubleshooting Steps:
  1. Check the secondary air pump.
  2. Inspect vacuum lines for leaks.
  3. Test the valve.

5.5 P0420 – Catalyst System Efficiency Below Threshold (Bank 1)

• Meaning: The catalytic converter is not functioning efficiently.
• Possible Causes:
  • Faulty catalytic converter
  • Faulty O2 sensors
  • Exhaust leaks
• Troubleshooting Steps:
  1. Check for exhaust leaks.
  2. Test the O2 sensors.
  3. Replace the catalytic converter.

5.6 P0102 – Mass or Volume Air Flow Circuit Low Input

• Meaning: The signal from the mass air flow (MAF) sensor is too low.
• Possible Causes:
  • Dirty or faulty MAF sensor
  • Wiring issues
• Troubleshooting Steps:
  1. Clean the MAF sensor.
  2. Check the wiring to the MAF sensor.
  3. Replace the MAF sensor.

5.7 P1624 – Control Module Self-Test Memory Failure

• Meaning: Internal fault within the Engine Control Module (ECM).
• Possible Causes:
  • ECM failure
  • Wiring issues
• Troubleshooting Steps:
  1. Check wiring connections to the ECM.
  2. Replace the ECM.

5.8 P1188 – Mixture Control (Bank 1)

• Meaning: Fuel trim at limit, bank 1.
• Possible Causes:
  • Vacuum leak
  • Faulty O2 sensor
  • Dirty or faulty fuel injectors
• Troubleshooting Steps:
  1. Inspect vacuum lines for leaks.
  2. Check O2 sensor readings.
  3. Clean or replace fuel injectors.

5.9 P0720 – Output Speed Sensor Circuit Malfunction

• Meaning: Problem with the output speed sensor circuit, often related to the transmission.
• Possible Causes:
  • Faulty output speed sensor
  • Wiring issues
• Troubleshooting Steps:
  1. Check the output speed sensor.
  2. Inspect wiring to the sensor.

5.10 P1519 – Camshaft Position Actuator A, Bank 1 Malfunction

• Meaning: Problem with the camshaft position actuator on bank 1.
• Possible Causes:
  • Faulty camshaft position sensor
  • Wiring issues
• Troubleshooting Steps:
  1. Check the camshaft position sensor.
  2. Inspect wiring to the sensor.

6. Advantages of Using OBD2-SCANNER.EDU.VN for Your Diagnostic Needs

Choosing OBD2-SCANNER.EDU.VN for your diagnostic needs offers numerous advantages, from expert guidance to a wide range of high-quality OBD2 scanners. Here’s how we can help you keep your 1999 E46 running smoothly:

6.1 Expert Guidance and Support

At OBD2-SCANNER.EDU.VN, we pride ourselves on providing expert guidance and support to our customers. Our team of experienced technicians can help you:

• Choose the right OBD2 scanner for your specific needs
• Understand diagnostic trouble codes (DTCs)
• Troubleshoot complex issues
• Perform maintenance and repairs

6.2 Wide Selection of OBD2 Scanners

We offer a wide selection of OBD2 scanners from leading brands, ensuring you can find the perfect tool for your 1999 E46. Our range includes:

• Basic code readers for simple diagnostics
• Advanced scanners with real-time data monitoring
• Professional-grade tools with bi-directional control
• BMW-specific scanners for in-depth diagnostics

6.3 High-Quality Products

We only offer high-quality OBD2 scanners that have been thoroughly tested and vetted by our team. This ensures that you receive a reliable and accurate tool that will provide years of service.

6.4 Competitive Prices

We strive to offer competitive prices on all our OBD2 scanners, making it affordable for you to invest in the tools you need to maintain your 1999 E46.

6.5 Easy-to-Navigate Website

Our website, OBD2-SCANNER.EDU.VN, is designed to be user-friendly and easy to navigate. You can quickly find the products you need, access helpful resources, and place your order with ease.

6.6 Fast Shipping and Delivery

We understand that you need your OBD2 scanner quickly, so we offer fast shipping and delivery options to get your tool to you as soon as possible.

6.7 Comprehensive Resources

In addition to offering high-quality products, we also provide a wealth of resources to help you diagnose and repair your 1999 E46. Our resources include:

• Detailed product descriptions
• User manuals
• Troubleshooting guides
• Blog articles
• Video tutorials

6.8 Customer Satisfaction

At OBD2-SCANNER.EDU.VN, customer satisfaction is our top priority. We are committed to providing excellent service and support to ensure that you are completely satisfied with your purchase.

6.9 Contact Information

If you have any questions or need assistance, please don’t hesitate to contact us:

• Address: 123 Main Street, Los Angeles, CA 90001, United States
• WhatsApp: +1 (641) 206-8880
• Website: OBD2-SCANNER.EDU.VN

6.10 Real-World Examples of Success

Many of our customers have successfully used our OBD2 scanners and resources to diagnose and repair their 1999 E46 vehicles. For example, one customer was able to diagnose a faulty O2 sensor using our Innova 3160g scanner and our troubleshooting guide. Another customer used our Autel MaxiCOM MK808 to perform a service reset after changing the oil in their E46.

By choosing OBD2-SCANNER.EDU.VN, you can be confident that you are getting the best products, resources, and support for your diagnostic needs.

7. Maintaining Your 1999 E46 with OBD2 Scanners

Regular maintenance is key to keeping your 1999 E46 running smoothly. Using an OBD2 scanner as part of your maintenance routine can help you identify and address potential issues before they become major problems.

7.1 Regular Diagnostic Scans

Perform regular diagnostic scans (e.g., monthly or quarterly) to check for any stored DTCs. This can help you catch minor issues before they escalate.

7.2 Monitoring Real-Time Data

Periodically monitor real-time data streams to ensure that your engine is operating within normal parameters. Pay attention to:

• Engine temperature
• O2 sensor readings
• Fuel trim levels
• MAF sensor readings

7.3 Addressing Issues Promptly

If you find any DTCs or abnormal data readings, address the issues promptly. Delaying repairs can lead to more significant problems and increased costs.

7.4 Keeping Records

Keep detailed records of all diagnostic scans, repairs, and maintenance performed on your 1999 E46. This can help you track the vehicle’s history and identify recurring issues.

7.5 Updating Your Scanner

Regularly update your OBD2 scanner’s software to ensure it remains compatible with your vehicle and has the latest code definitions and diagnostic capabilities.

7.6 Checking for TSBs

Before performing any repairs, check for Technical Service Bulletins (TSBs) related to the DTCs. TSBs often provide detailed diagnostic and repair procedures that can save you time and money.

7.7 Cleaning Sensors

Periodically clean sensors such as the MAF sensor and O2 sensors to ensure they are functioning correctly. Dirty sensors can cause inaccurate readings and performance issues.

7.8 Inspecting Wiring

Regularly inspect wiring harnesses and connectors for any signs of damage or corrosion. Damaged wiring can cause a variety of issues, including intermittent faults and communication problems.

7.9 Checking Vacuum Lines

Inspect vacuum lines for leaks or cracks. Vacuum leaks can cause a variety of issues, including poor engine performance and increased emissions.

7.10 Maintaining Fluids

Ensure that all fluids (e.g., engine oil, coolant, transmission fluid) are at the correct levels and are in good condition. Low or contaminated fluids can cause damage to various components.

By following these maintenance tips and using an OBD2 scanner regularly, you can keep your 1999 E46 running smoothly and reliably for years to come.

8. Addressing Common Concerns and Misconceptions

Several common concerns and misconceptions surround OBD2 scanners and their use with older vehicles like the 1999 E46. Let’s address some of these:

8.1 “OBD2 Scanners Don’t Work on Older Cars”

• Reality: While older vehicles may have different diagnostic protocols, OBD2 scanners are designed to be backward-compatible. As long as your 1999 E46 has an OBD2 port, a compatible scanner should work.

8.2 “All OBD2 Scanners Are the Same”

• Reality: OBD2 scanners vary widely in terms of features, compatibility, and performance. Some scanners only read basic codes, while others offer advanced features like real-time data monitoring and bi-directional control.

8.3 “Clearing Codes Fixes the Problem”

• Reality: Clearing codes only removes the symptom, not the underlying problem. If a code reappears after being cleared, it indicates that the issue still needs to be addressed.

8.4 “You Need to Be a Mechanic to Use an OBD2 Scanner”

• Reality: While some advanced diagnostic procedures require technical expertise, basic OBD2 scanning is relatively straightforward. Many scanners have user-friendly interfaces and provide code definitions and troubleshooting tips.

8.5 “OBD2 Scanners Can Damage Your Car”

• Reality: OBD2 scanners are designed to be safe for use on compatible vehicles. However, it’s essential to choose a reputable scanner and follow the manufacturer’s instructions carefully.

8.6 “You Can Only Use BMW-Specific Scanners on a BMW”

• Reality: While BMW-specific scanners offer more in-depth diagnostics, generic OBD2 scanners can still read basic codes and provide valuable information.

8.7 “OBD2 Scanners Can Void Your Warranty”

• Reality: Using an OBD2 scanner to diagnose issues on your vehicle will not void your warranty, as long as you follow the manufacturer’s recommendations and avoid making unauthorized modifications.

8.8 “OBD2 Scanners Can Perform Miraculous Repairs”

• Reality: OBD2 scanners are diagnostic tools, not repair tools. They can help you identify the source of a problem, but they cannot fix it.

8.9 “Expensive Scanners Are Always Better”

• Reality: While expensive scanners often offer more features and capabilities, they are not always necessary for basic diagnostics. A mid-range scanner may be sufficient for many users.

8.10 “You Only Need an OBD2 Scanner When Something Goes Wrong”

• Reality: Using an OBD2 scanner as part of your regular maintenance routine can help you identify potential issues before they become major problems, saving you time and money in the long run.

9. What To Do After Scanning: Next Steps for 1999 E46 Owners

So, you’ve scanned your 1999 E46 and retrieved some codes – what’s next? Here’s a breakdown of the steps you should take to effectively address the issues and get your BMW back in top shape.

9.1 Document the Codes

Before you do anything, write down all the diagnostic trouble codes (DTCs) that your scanner has provided. Include any freeze frame data, which captures the conditions when the code was triggered (e.g., engine speed, load, temperature). This information is valuable for further diagnosis.

9.2 Research Each Code

Use your scanner’s built-in database or online resources to research each code. Understand what the code means, what systems it affects, and what the possible causes are. Reputable websites like OBD-Codes.com and BMW forums can be very helpful.

9.3 Prioritize the Codes

If you have multiple codes, prioritize them based on severity and potential impact on your vehicle’s performance. Address critical codes first, as they may be causing other issues.

9.4 Perform Visual Inspections

Based on the codes, perform visual inspections of the affected components and systems. Look for:

• Damaged or disconnected wiring
• Leaking fluids
• Cracked or broken hoses
• Corroded connectors

9.5 Test Components

Use a multimeter, test light, or other diagnostic tools to test the components related to the codes. For example, if you have a code for a faulty O2 sensor, test the sensor’s voltage and resistance.

9.6 Consult Technical Service Bulletins (TSBs)

Check for Technical Service Bulletins (TSBs) related to your vehicle and the specific codes. TSBs provide detailed diagnostic and repair procedures that can save you time and effort.

9.7 Seek Professional Advice

If you’re unsure about any of the diagnostic or repair steps, seek professional advice from a qualified mechanic. They can provide expert guidance and perform more advanced testing.

9.8 Perform Repairs

Based on your findings, perform the necessary repairs. This may involve replacing faulty components, repairing wiring, or cleaning sensors.

9.9 Clear the Codes

After performing the repairs, clear the DTCs using your OBD2 scanner.

9.10 Test Drive and Monitor

Take your 1999 E46 for a test drive and monitor the systems to ensure the repairs were effective. Use your OBD2 scanner to check for any reappearing codes or abnormal data readings.

9.11 Maintain Records

Keep detailed records of all diagnostic steps, repairs, and parts replaced. This will help you track the vehicle’s history and identify any recurring issues.

9.12 Follow-Up Scans

Perform regular follow-up scans (e.g., weekly or monthly) to check for any new codes or issues.

10. FAQ About OBD2 Scanners and the 1999 E46

Here are some frequently asked questions about OBD2 scanners and their use with the 1999 BMW E46:

10.1 What is an OBD2 Scanner?

An OBD2 scanner is a diagnostic tool used to read and interpret data from a vehicle’s on-board diagnostic system. It can help you identify issues with the engine, transmission, and other systems.

10.2 Where is the OBD2 Port Located on a 1999 E46?

The OBD2 port is typically located under the dashboard on the driver’s side. Some models may also have a round connector under the hood.

10.3 Will Any OBD2 Scanner Work on a 1999 E46?

Most generic OBD2 scanners should work on a 1999 E46, but it’s essential to choose a scanner that is compatible with BMW vehicles and offers the features you need (e.g., real-time data monitoring, ABS/SRS diagnostics).

10.4 Can I Use an OBD2 Scanner to Reset the Service Indicator on My 1999 E46?

Some advanced OBD2 scanners can reset the service indicator, but this feature may not be available on all scanners. BMW-specific scanners are more likely to offer this capability.

10.5 How Do I Update the Software on My OBD2 Scanner?

The update process varies depending on the scanner model. Typically, you will need to connect the scanner to a computer via USB and use the manufacturer’s software to download and install the latest updates.

10.6 Can an OBD2 Scanner Tell Me What’s Wrong with My Car?

An OBD2 scanner can provide diagnostic trouble codes (DTCs) that indicate potential issues. However, it’s up to you to interpret the codes and perform further diagnostics to identify the root cause of the problem.

10.7 Is It Safe to Clear Codes with an OBD2 Scanner?

Yes, it is generally safe to clear codes with an OBD2 scanner, but you should only do so after you have addressed the underlying issue. Clearing codes without fixing the problem will only temporarily remove the symptom, and the code will likely reappear.

10.8 Can I Use an OBD2 Scanner to Improve My Car’s Performance?

OBD2 scanners are primarily diagnostic tools, but some advanced scanners offer features like performance monitoring and data logging that can help you optimize your car’s performance.

10.9 Do I Need a Special OBD2 Scanner for BMW Vehicles?

While generic OBD2 scanners can work on BMW vehicles, BMW-specific scanners offer more in-depth diagnostics and can access additional systems and features.