Hemi MDS OBD2: What Is It And How To Disable It?

Hemi Mds Obd2 refers to disabling the cylinder deactivation system in Hemi engines using an OBD2 device. This article, brought to you by MERCEDES-DIAGNOSTIC-TOOL.EDU.VN, will explore options to disable MDS. We’ll cover performance tuning, diagnostic tools, and troubleshooting.

1. What Is Hemi MDS OBD2 and Why Disable It?

Multi-Displacement System (MDS), often referred to as cylinder deactivation, is a technology used in some Hemi engines to improve fuel efficiency. The system shuts down four of the eight cylinders under light load conditions, effectively turning the V8 engine into a V4. While this improves gas mileage, some owners and mechanics report that it can cause issues like:

• Oil Consumption: MDS can contribute to increased oil consumption.
• Unpleasant Noises: Some drivers report unusual noises when the MDS engages or disengages.
• Potential Reliability Concerns: The MDS lifters are known to be a potential point of failure.
• Performance Issues: Some enthusiasts dislike the transition between V8 and V4 modes.

Disabling MDS ensures the engine runs on all eight cylinders at all times, preventing these issues and improving performance.

2. Understanding OBD2 and Diagnostic Tools

OBD2 (On-Board Diagnostics II) is a standardized system that provides real-time data and diagnostic trouble codes (DTCs) from a vehicle’s computer. Diagnostic tools that connect to the OBD2 port can read these codes, reset the check engine light, and perform various functions like disabling MDS. MERCEDES-DIAGNOSTIC-TOOL.EDU.VN offers a range of OBD2 diagnostic tools.

3. Methods to Disable Hemi MDS Using OBD2 Devices

Several methods can be used to disable Hemi MDS using OBD2 devices or through custom tuning:

3.1 Range Technology MDS Manager

One of the most straightforward methods is to use a device like the Range Technology MDS Manager. According to Range Technology’s website, this device plugs into the OBD2 port and disables MDS without requiring any tuning or programming. Once plugged in, the device prevents the engine from switching to four-cylinder mode, ensuring it operates in V8 mode at all times.

3.2 Custom Tuning with OBD2 Programmers

Custom tuning involves reprogramming the engine control unit (ECU) to disable MDS. This can be done using OBD2 programmers from companies like DiabloSport or HP Tuners.

• DiabloSport: Their programmers allow users to adjust various engine parameters, including disabling MDS.
• HP Tuners: This platform provides comprehensive tuning capabilities, allowing experienced tuners to customize the ECU settings to their preferences.

3.3 Professional Tuning Shops

If you are not comfortable tuning the ECU yourself, a reputable performance shop can disable MDS. These shops use specialized software and equipment to reprogram the ECU, ensuring MDS is permanently disabled.

4. Step-by-Step Guide to Disabling MDS with Range Technology MDS Manager

Using the Range Technology MDS Manager is a simple process:

1. Purchase the Device: Buy the MDS Manager from Range Technology’s website or an authorized dealer.
2. Plug into OBD2 Port: Locate the OBD2 port, usually under the dashboard on the driver’s side. Plug the MDS Manager into the port.
3. Start the Engine: Start your vehicle’s engine.
4. Confirmation: The MDS Manager will automatically disable MDS. There is no need for any further programming or setup. The device will keep MDS disabled as long as it is plugged in.

5. Step-by-Step Guide to Disabling MDS with DiabloSport Tuner

Disabling MDS with a DiabloSport tuner involves these steps:

1. Purchase a DiabloSport Tuner: Buy a DiabloSport programmer compatible with your vehicle.
2. Connect the Tuner: Plug the DiabloSport tuner into the OBD2 port.
3. Follow On-Screen Prompts: The tuner will guide you through the process. Select the option to disable MDS.
4. Install the Tune: Follow the instructions to install the custom tune that disables MDS.
5. Test Drive: After installation, take your vehicle for a test drive to ensure MDS is disabled.

6. Common Problems and Troubleshooting

Even with these tools, problems can arise. Here are some common issues and how to troubleshoot them:

• Check Engine Light: If the check engine light comes on after disabling MDS, use an OBD2 scanner to read the DTCs. This can help identify any underlying issues.
• Device Not Working: Ensure the OBD2 device is compatible with your vehicle. Contact the manufacturer for support if needed.
• MDS Still Activating: Double-check that the MDS disable feature is properly enabled in the tuning software.

7. The Benefits of Disabling MDS

Disabling MDS can offer several benefits:

• Eliminating Potential Issues: Prevents oil consumption, unusual noises, and potential lifter failures associated with MDS.
• Consistent Performance: Ensures the engine runs on all eight cylinders for consistent power delivery.
• Improved Throttle Response: Some drivers report improved throttle response and overall driving experience.

8. Drawbacks of Disabling MDS

While there are benefits, there are also potential drawbacks:

• Reduced Fuel Economy: Running on all eight cylinders at all times will reduce fuel economy.
• Increased Emissions: Higher fuel consumption can lead to increased emissions.
• Potential Wear: While it prevents MDS-related issues, running on all cylinders can increase wear on other engine components.

9. Hemi Engine Problems Related to MDS

MDS can cause or exacerbate certain engine problems:

• Lifter Failure: MDS lifters are known to fail, leading to engine damage.
• Oil Consumption: The system can increase oil consumption due to the way cylinders are deactivated and reactivated.
• Spark Plug Fouling: Inactive cylinders can experience spark plug fouling.

10. Alternatives to Disabling MDS via OBD2

If you do not want to use an OBD2 device, other options are available:

10.1 Mechanical MDS Delete

This involves physically removing the MDS components (lifters and camshaft) and replacing them with non-MDS parts. This is a more involved and expensive option, but it permanently eliminates MDS.

10.2 Custom Tuning by Professionals

A professional tuning shop can create a custom tune that disables MDS without using an OBD2 device. This involves directly reprogramming the ECU.

11. Choosing the Right OBD2 Tool for Your Needs

Selecting the correct OBD2 tool depends on your specific needs and budget. Here’s a comparison of some popular options:

Feature	Range Technology MDS Manager	DiabloSport Tuner	HP Tuners
MDS Disable	Yes	Yes	Yes
Other Tuning	No	Yes	Yes
Price	$200	$400 – $1,000	$500 – $2,000
Ease of Use	Very Easy	Moderate	Advanced
Vehicle Support	Limited	Extensive	Extensive

12. Cost Analysis: OBD2 Device vs. Professional Tuning

The cost of disabling MDS varies depending on the method:

• OBD2 Device (e.g., Range Technology): Around $200
• DiabloSport Tuner: $400 – $1,000 (depending on features)
• Professional Tuning: $500 – $1,500 (depending on the shop and complexity)
• Mechanical MDS Delete: $3,000+ (includes parts and labor)

13. Legal Considerations and Warranty Implications

Disabling MDS may have legal and warranty implications:

• Warranty: Modifying the ECU or disabling emissions-related systems can void your vehicle’s warranty.
• Emissions Regulations: Check your local emissions regulations to ensure disabling MDS is legal in your area.

14. Maintaining Your Hemi Engine After Disabling MDS

After disabling MDS, it’s crucial to maintain your engine properly:

• Regular Oil Changes: Follow the manufacturer’s recommended oil change intervals.
• Monitor Oil Levels: Check oil levels regularly to ensure there are no leaks or excessive consumption.
• Spark Plug Maintenance: Replace spark plugs as recommended.

15. Resources for Hemi Owners

Numerous online resources can help Hemi owners:

• Online Forums: Websites like LXForums and Mopar Forums provide valuable information and community support.
• Manufacturer Websites: Check the official Mopar website for technical specifications, recalls, and service information.
• Repair Manuals: Purchase a repair manual specific to your vehicle for detailed repair and maintenance procedures.

16. Understanding Diagnostic Trouble Codes (DTCs)

Diagnostic Trouble Codes (DTCs) are codes stored in the vehicle’s computer when a problem is detected. Use an OBD2 scanner to read these codes and understand what they mean. Common DTCs related to MDS include:

• P3400-P3499: Cylinder Deactivation System Codes
• P0300: Random/Multiple Cylinder Misfire Detected

17. The Role of Software Updates in OBD2 Devices

Software updates are essential for OBD2 devices to maintain compatibility with the latest vehicle models and software versions. Regularly update your device to ensure it functions correctly.

18. Advanced Tuning Options and Considerations

Advanced tuning involves more than just disabling MDS. It includes adjusting various engine parameters to optimize performance. This requires a thorough understanding of engine management systems and should be done by experienced tuners.

19. Comparing Different OBD2 Scanner Brands

Several brands offer reliable OBD2 scanners. Here’s a brief comparison:

• Snap-On: Known for professional-grade features and accuracy.
• Autel: Offers a wide range of scanners for both DIY enthusiasts and professionals.
• Innova: Popular among DIYers for their ease of use and affordability.
• BlueDriver: A smartphone-based scanner that offers advanced diagnostics.

20. Safety Precautions When Working with OBD2 Ports and Vehicle Electronics

When working with OBD2 ports and vehicle electronics, follow these safety precautions:

• Disconnect Battery: Before performing any major electrical work, disconnect the negative battery terminal.
• Use Proper Tools: Use the correct tools for the job to avoid damaging connectors or wiring.
• Follow Instructions: Always follow the manufacturer’s instructions when using OBD2 devices or tuning software.

21. How Often Should You Scan Your Car for Codes?

It’s a good practice to scan your car for codes:

• When the Check Engine Light Comes On: Immediately scan for codes to diagnose the issue.
• Periodically: Scan every few months to check for any potential problems.
• After Repairs: Scan after completing any repairs to ensure everything is working correctly.

22. Decoding VIN Numbers for Hemi Engine Information

The Vehicle Identification Number (VIN) contains valuable information about your vehicle, including the engine type. Use a VIN decoder to identify if your vehicle has a Hemi engine and if it is equipped with MDS.

23. Understanding the Hemi Engine Family

The Hemi engine family includes various iterations, such as the 5.7L, 6.1L, 6.2L (Hellcat), and 6.4L (392). Each engine has specific characteristics and may require different tuning approaches.

24. The Future of Cylinder Deactivation Technology

Cylinder deactivation technology is continuously evolving. Newer systems are more sophisticated and aim to minimize the drawbacks associated with older MDS systems.

25. Environmental Impact of Disabling MDS

Disabling MDS increases fuel consumption and emissions, which can have a negative environmental impact. Consider the environmental implications before making this modification.

26. Top Myths About Hemi Engines and MDS

There are many myths surrounding Hemi engines and MDS. Some common ones include:

• Myth: Disabling MDS will immediately increase horsepower. (Reality: The increase is minimal.)
• Myth: MDS always causes engine problems. (Reality: It can contribute to certain issues but doesn’t always cause problems.)
• Myth: All Hemi engines have MDS. (Reality: Not all Hemi engines are equipped with MDS.)

27. Choosing the Right Oil for Your Hemi Engine

Using the correct oil is critical for maintaining your Hemi engine:

• Follow Manufacturer Recommendations: Use the oil viscosity and specification recommended in your vehicle’s owner’s manual.
• Synthetic Oil: Consider using synthetic oil for better protection and performance.
• High-Quality Filters: Use high-quality oil filters to ensure proper filtration.

28. The Importance of Regular Maintenance for Hemi Engines

Regular maintenance is key to keeping your Hemi engine running smoothly:

• Oil Changes: Change the oil and filter at the recommended intervals.
• Air Filter: Replace the air filter regularly.
• Spark Plugs: Replace spark plugs as needed.
• Fluid Checks: Check and top off all fluids, including coolant, brake fluid, and power steering fluid.

29. Community Insights and Experiences with MDS Disabling

Many Hemi owners have shared their experiences with disabling MDS on online forums and communities. These insights can provide valuable information and tips.

30. Hemi MDS OBD2: A Summary

Disabling Hemi MDS via OBD2 is a popular solution for owners seeking to avoid potential issues associated with cylinder deactivation. While there are benefits, it’s important to consider the potential drawbacks and legal implications. MERCEDES-DIAGNOSTIC-TOOL.EDU.VN offers a comprehensive range of diagnostic tools and information to help you make informed decisions about your vehicle.

FAQ: Hemi MDS OBD2

1. What is Hemi MDS?

Hemi MDS (Multi-Displacement System) is a cylinder deactivation technology used in some Hemi engines to improve fuel efficiency by shutting down four cylinders under light load.

2. Why would I want to disable Hemi MDS?

Disabling MDS can prevent potential issues like oil consumption, unusual noises, lifter failures, and inconsistent performance.

3. How do I disable Hemi MDS using an OBD2 device?

You can use devices like the Range Technology MDS Manager or DiabloSport tuners, which plug into the OBD2 port and disable MDS.

4. Is it legal to disable Hemi MDS?

It depends on your local emissions regulations. Check your local laws to ensure it is legal in your area.

5. Will disabling Hemi MDS void my vehicle’s warranty?

Yes, modifying the ECU or disabling emissions-related systems can void your vehicle’s warranty.

6. What are the benefits of disabling Hemi MDS?

Benefits include eliminating potential issues, ensuring consistent performance, and potentially improving throttle response.

7. What are the drawbacks of disabling Hemi MDS?

Drawbacks include reduced fuel economy and increased emissions.

8. How much does it cost to disable Hemi MDS?

The cost varies: Range Technology MDS Manager is around $200, DiabloSport tuners range from $400 to $1,000, and professional tuning ranges from $500 to $1,500.

9. Can I re-enable Hemi MDS after disabling it?

Yes, if you used an OBD2 device or tuner, you can typically re-enable MDS by unplugging the device or restoring the original tune.

10. What is the best OBD2 scanner for disabling Hemi MDS?

The best scanner depends on your needs. Range Technology MDS Manager is simple for MDS disable only, while DiabloSport and HP Tuners offer more tuning options.

At MERCEDES-DIAGNOSTIC-TOOL.EDU.VN, we understand the complexities of maintaining and modifying your Mercedes-Benz. Whether you’re dealing with a check engine light, looking to unlock hidden features, or need assistance with routine maintenance, we’re here to help.

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