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Focus ST ECU tune (COBB Accessport)

Your Focus ST

Pick your year to see what fits.

Every US Focus ST (2013–2018) is a hatchback with a 6-speed manual and the same 2.0L EcoBoost engine, so the same parts fit every year.

+20–35 whp (est.)
Easy$600–$70045–60 min
All Focus ST mods

Why do it

The biggest gain for the money on the Focus ST. The Accessport flashes a ready-made map that matches your parts and fuel, and doubles as a gauge and code reader.

Heads up

Never unplug the cable or turn off the car while the Accessport is flashing. Wait for it to say it's done.

Tools you'll need

Parts to buy

Double-check fitment before buying.

Before you start

  • If you've ever used a different tuner on this car, flash it back to stock with that tuner first. The Accessport can't install over another tuner's file.
  • Before you start, plug the Accessport into your computer and download the map that matches your parts and fuel from COBB's site (stage 1 for a stock car, for example).
  • Connect a battery charger if you have one. Turn off the lights, radio and fan. Flashing draws a lot of power, and a dead battery mid-flash can brick the computer.
  • The Accessport saves your stock file. Use it to go back to stock before a dealer visit or selling the car.

Video guide

Focus ST COBB Accessport V3 install
by CJ Pony Parts on YouTube

The same Accessport we list. He speeds up the flashing part; yours takes about 20–25 minutes the first time.

Watch the whole video

Steps

  1. Get your map ready

    • Connect the Accessport to your computer with the USB cable and use COBB's software to load the maps you want onto it.
    • Pick the map for your fuel (91 or 93 octane) and your parts. Maps for intakes, intercoolers and more are all there for later.
    Watch this step (0:41–1:28)

  2. Plug it into the car

    • Find the OBD-II port under the dash on the driver's side. Pull its cover down and plug the cable in.
    • Route the other end up the dash and plug it into the Accessport. It turns on by itself.
    Watch this step (1:28–1:49)

  3. Start the install

    • Choose Install from the menu. Check that the vehicle it shows matches your car (US Focus ST) and press Continue.
    Watch this step (2:14–2:34)

  4. Pick your map

    • Select the map that matches your mods and fuel.
    • Connect a battery charger now if you have one, and make sure the lights and radio are off.
    Watch this step (2:34–3:01)

  5. Let it flash

    • The Accessport saves your stock data, prepares the computer and then flashes the new map. Follow the prompts on screen.
    • The first install takes about 20–25 minutes. Don't touch anything while it runs.
    Watch this step (3:01–3:50)

  6. Finish the install

    • When it asks, turn the ignition off and back on. A check mark means the install worked.
    • Turn the ignition off once more, then start the car and let it idle.
    Watch this step (3:42–4:11)

  7. Set up the gauges (optional)

    • The Accessport can show live gauges. Good ones to watch: air-fuel ratio, boost and charge air temperature.
    • You can also set a shift light and use the 0–60 timer. Only use timers off public roads.
    Watch this step (4:11–6:41)

  8. Test drive

    • Drive gently at first and watch the gauges. Air-fuel should get richer (lower number) as boost comes up.
    • Mount the Accessport where you can glance at it without taking your eyes off the road for long.
    Watch this step (7:18–8:15)

How to know it worked

Did this guide work for you?

Safety first

  • Park on flat ground, set the parking brake and chock the wheels.
  • Never get under a car held up only by a jack. Use jack stands.
  • Let the engine and exhaust cool first.
  • Disconnect the battery before unplugging electrical parts.
  • Wear safety glasses.
  • If something doesn't match your car, stop and ask a shop.

Follow your part's instructions and your service manual's torque specs.