Cobb Accessport V3 Subaru 15+ STi & WRX VA - AP3-SUB-004

The COBB Tuning Accessport V3 AP3-SUB-004 is a hand-held ECU tuner & data logging device designed for the 2015-2021 Subaru WRX & STi and 2014-2018 Forester XT. Whether your car is completely stock or heavily modified, an Accessport should be your very first performance mod. It completely transforms how your Subaru drives by sharpening laggy factory throttle response, cleaning up rev hang, flattening out flat spots, and adding a massive chunk of usable mid-range torque. Buy with confidence from an authorized Cobb Tuning dealer with a 60 day return policy, free shipping, and a loyalty rewards points program!

Out of the box, the Accessport V3 lets you flash COBB’s pre-loaded Off-The-Shelf (OTS) maps in minutes.
Please note: COBB’s pre-loaded OTS maps are strictly designed for vehicles using a completely stock or 100% COBB-brand bolt-ons. If your Subaru WRX or STi runs a mix of different aftermarket brands, or if you want to get the safest maximum power out of your specific setup, you need a custom tune. We offer a custom remote e-tuning service from our certified Cobb Protuner Clark Turner. Clark started tuning Subaru's back in 2004 and has tuned thousands of them. You can add a custom e-tune to your order using the Add All to Cart option on this product page.

Beyond tuning, the Accessport acts as your in-cabin digital gauge cluster. Its large, high-resolution color screen mounts right to your dash to monitor critical engine vitals in real-time. You can keep an eye on boost pressure, air-fuel ratios, intake temps, and critical health metrics like fine learning knock and feedback correction. The high-speed data logging features allow you to record your pulls, diagnose annoying check engine lights, and save clean CSV files to send straight to your tuner for review.

Enthusiasts, track teams, and professional tuners all run the Accessport V3 because it is incredibly reliable, easy to use, and delivers proven results.

Not sure what Accessport you need for your Subaru - Use our Which COBB Accessport Fits Your Subaru? Buyer’s Guide!

COBB Tuning AP3-SUB-004 - Key Features

• Crisp, full-color screen that is easy to read in direct sunlight or at night
• Customizable gauge layouts that monitor up to six engine parameters simultaneously
• In-vehicle sticky mount with an integrated on/off switch so it won't drain your battery
• Pre-loaded OTS maps for multiple modification stages and fuel octanes
• Fully compatible with professional custom dyno tunes and remote e-tunes
• High-speed live monitoring and advanced data logging capabilities
• Built-in OBD-II diagnostic tool to read and clear check engine lights yourself
• Built-in performance timers for tracking 0–60 mph sprints and quarter-mile times
• Completely reversible—unmarry the device to restore your factory ECU settings at any time
• Interchangeable faceplates to match your interior styling
• Fast internal processor and expanded memory for snappy screen updates and quick flashes

Real-World Power Gains

The Accessport V3 wakes up your engine by rewriting conservative factory ECU mapping. While exact numbers always depend on your car's condition, local weather, and fuel quality, these are the typical results you can expect:

• A standard Stage 1 OTS map on 93 octane typically adds 15-25 WHP and 25–35 WTQ peak power
• Massive changes to mid-range torque & power, meaning your car pulls significantly harder during everyday driving without needing to drop three gears. Adds 25-40 WHP and 35-50 WTQ to the mid-range.
• Noticeably sharper throttle response and smooth, linear power delivery all the way to redline
• Significantly higher power ceilings when you pair the Accessport with a custom e-tune and physical bolt-ons like an intake, downpipe, or intercooler

Note: Real-world results vary based on fuel octane, altitude, and climate. For heavily modified vehicles running mixed-brand parts, a custom tune is required for safety and maximum performance.

COBB Tuning AP3-SUB-004 - Vehicle Fitment

Subaru WRX & STi

• 2015-2021 Subaru STi
• 2015-2021 Subaru WRX

Subaru Forester XT

• 2014-2018 Subaru Forester XT

Frequently Asked Questions

What does the Accessport actually do?

It plugs into your car's OBD-II port and overwrites the factory computer with a performance tune that adjusts boost, timing, and fueling. It also works as a live digital gauge display, data logger, and engine diagnostic tool.

Is the Accessport safe to use on a daily driver?

Yes, as long as you match the correct map to the exact parts installed on your car and use high-quality fuel, COBB’s tunes leave plenty of built-in safety margins for reliable daily commuting.

Can I uninstall it and go back to stock?

Yes. The Accessport has an "Unmarry" feature. Running this process completely removes the COBB software and restores your exact factory Subaru ECU file.

Do I need to buy other parts to use this?

No. The Stage 1 maps are engineered specifically for 100% bone-stock cars. You can install it on day one without changing a single part under the hood.

Can I run a tune from a professional tuner?

Yes. The Accessport is the most supported tuning platform for Subarus. It is the exact tool used by pro dyno tuners and remote e-tuners worldwide.

Will this void my factory warranty?

Flashing your ECU can affect powertrain warranty claims if a failure happens. Dealerships and manufacturers review modified vehicles on a case-by-case basis.

Can it read and clear check engine lights?

Yes. It reads standard diagnostic trouble codes (DTCs), gives you a description of the issue, and allows you to clear the code to turn off the light.

Can I use this on multiple cars?

The Accessport locks (marries) to one vehicle at a time. To use it on a different car, you must completely uninstall and unmarry it from the first vehicle first.

What's in the Box?

• COBB Accessport V3 Handheld Device (AP3-SUB-004)
• Heavy-duty OBD-II cable
• Micro-USB cable for data transfer & updates
• In-cabin dash mount with integrated power switch
• Alternative colored bezels/faceplates
• Padded protective storage case
• Quick-start guide

Warranty Information

COBB Tuning includes a 12-month limited warranty for the original buyer, protecting against defects in materials and manufacturing. This warranty does not cover accidental drops, screen cracks, water damage, improper installation, or unapproved modifications. Keep your store receipt, as proof of purchase is required for all warranty claims.