What Is an Access Port and Why It’s Important

You may have been doing a little research to find ways to add more power to your ride. In doing so, you may also have come across the term, access port or COBB access port. Upgrades for your vehicle can become confusing. This is especially true when the upgrade deals with your internal computer. Imagine this as opposed to an external component such as a turbocharger or supercharger.

So what exactly does an access port do? Is it worth dropping a good chunk of money to upgrade it? This article will attempt to shine some light on those questions. It also aims to provide some direction if you choose to tweak this aspect.

How Does an Access Port Work?

Tuning your access port will provide you with the most flexible and easy way to upgrade through use of your ECU. Inside your vehicle there is a computer that constantly monitors sensors throughout the system. It also controls the parameters of your engine to properly run and keeps it at peak performance. When you get inside those parameters and adjust them in an attempt to improve the engine’s performance, you are doing what is called flashing or re-flashing.

The access port plugs into the OBDII port of your vehicle so that it can talk to the computer and give it the new parameters you tell it you want. The new parameters will be saved to the ECU. They will be used instead of your default factory settings. You do not even have to worry about having to readjust every time you drive. This is because the parameters will override the default settings until you choose to change them again or switch them back.

How does this translate into more power? Well, allowing you to change parameters that involve fuel curves, timing, boost, etc. will give you the control to balance them out specifically for your build to get it reaching peak performance. Think of it as overclocking your vehicle.

General Specifications

  • Allows you to adjust things like: Timing, Fuelling curves, Boost curves;
  • Gives you the ability to tweak settings in the ECU to gain more power;
  • Replace conservative settings with more aggressive ones;
  • Gives you maps that are sometimes in real-time. This is in order to balance out your adjustments and see how it increases in power;
  • Simple and effective;
  • Offers two types of re-flashes: Base map, which replaces factory settings until you change them again. Or, Real-time map, which will not save to the ECU. So it is less permanent and allows you to revert to the original settings with a reset.

PROs and CONs of Tuning Your Vehicle with an Access Port


  • Gives you control over the parameters of your vehicle’s ECU;
  • Offers permanent and non-permanent options. These give you flexibility to change your parameters often or revert back to previous ones;
  • Maps give you a visual means to really see how the new parameters are affecting your performance;
  • Easily to install;
  • Gives you an added way to enhance the performance and power of your vehicle.


  • You have to really know how to use it. If you just change parameters without knowing how to balance them out, you may risk damaging internal components through strain;
  • Certain access port re-flashes only allow you to use preinstalled maps;
  • Re-tunes are usually needed when additional vehicle modifications add to your build;
  • Can be a more expensive alternative to other methods like Romraider and Opensource;
  • May see more expense in maintenance. This is because it is important to keep up on maintenance with better fluids. Furthermore, fluid changes more often due to the added stress on your system.

Examples of Access Port Parts

COBB Subaru Accessport V3 (AP3-SUB-003)

COBB is one of the most notable companies that help you realize the full abilities of your vehicle. They have spent over a decade researching and developing upgrade paths that help you go from substandard to help you get to a car you are proud to drive. They strive to help maximize power through the access port as well as other components they have available. Many look to them as a one stop shop.

Customers have high reviews of this product saying that they only wish they would have purchased it sooner. They can really feel the difference in performance. Also, they say that it is easy to monitor up to six maps in real-time to really get the most out of the product.

SCT X4 Powerflash

Founded in 2003, the passion of the SCT brand has been driven to provide greater performance to enthusiasts. They believe that engine management is a key factor in realizing the highest performance levels in a vehicle.

This product is said to be very easy to use by reviewers. It has pre-loaded maps that are quick to install and have adjustable vehicle parameters. They also love the built in WiFi. It makes it very simple to do needed updates to the software. It is also more affordable than other tuners.

AEM Infinity-6 Stand-Alone Programmable Engine Management System

Another brand making the rounds as a favorite engine management option is AEM. This product allows the user to adjust all parameters associated with engine function. Reviewers love the racing capabilities and quick processor they experience at a much lower price.

They can also really feel the increase in responsiveness and power after applying new parameters. Also, the set up wizard made it easy to do an initial install.

Wrapping Up

When looking to add power to your build, do not just look to mechanical components. Remember the access port that allows you to tweak computer parameters as well. This will give you a means to gaining overall power through all aspects of your vehicle. The access port will allow you to adjust parameters more aggressively. You can also monitor the differences made after adjustments.

What types of modifications do you have? Were they enhanced more when you added an access port? Leave your experiences here to help others looking to pump up the power hidden under the hood.

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