BEFORE ORDERING
Get the car ready
Check your tools, wideband and fuel before buying equipment or a tune.
Start with the preparation checklist →TUNING KNOWLEDGE / START HERE
Tuning help.
Start here.
Choose the task you need below, or explore the equipment and preparation guidance for your Subaru. Not sure what your setup needs? Ask before buying.
By Keith Fields · Updated October 31, 2026. No payment required to ask about compatibility.
What do you need help with?
I HAVE MY TUNE FILE
Flash my car
Transfer the file, prepare battery support and follow the flashing steps.
Open the Accessport flashing steps →KEITH REQUESTED A LOG
Record and send data
Set the channels for your platform, record the requested test and export the CSV.
Open the logging instructions →Logging parameters: EJ WRX / STI · 2015–2021 WRX · 2022+ WRX · Porsche
FLASHING TOOLS
What do I need to flash my Subaru?
A tune file needs a compatible tool to write it to the ECU. A generic Bluetooth code reader does not replace a supported flashing device. The right route depends on the model year, engine, ECU and existing tune.
For a COBB Accessport tune
- A supported Accessport for your exact vehicle, with its OBD-II cable.
- A computer, USB data cable and COBB’s Accessport Manager for transferring files and logs.
- Stable vehicle battery support during programming.
- The correct tune file for your car, installed parts and fuel.
Before buying a used device
Confirm its part number and vehicle support, plus whether it is unmarried and ready for another car. An Accessport pairs with one vehicle at a time; a low used price does not establish that it can be installed on yours.
Send the device details and your car’s information before ordering a tune.
The Accessport writes the file; Accessport Manager transfers files between the handheld and computer. If you already use another system, an ECU swap or a standalone, ask me to confirm the supported hardware, software and any license requirements first.
Manufacturer references: COBB Accessport quick-start guide ↗ and Subaru Accessport manual ↗.
STI & EJ FUELING DATA
Why does my STI need a wideband?
A wideband measures exhaust oxygen so fueling can be evaluated as air/fuel ratio (AFR) or lambda. For remote tuning, I need that measurement recorded alongside the other engine data. A gauge you can watch is useful, but a gauge reading alone is not a usable tuning log.
EJ remote tuning requires an external wideband with an approved way to record AFR or lambda alongside the engine log. A factory oxygen-sensor reading, gauge display or gauge video does not replace that recorded data. Confirm the controller and logging connection with me before buying equipment.
For 2015–2017 FA20 WRX remote fueling work, an external wideband with approved recording is also required. Later FA20 and FA24 WRX measurement plans are reviewed for the specific setup.
On older EJ applications, the factory front oxygen sensor is not a substitute for the external measurement needed for this work. The added wideband does not mean removing the factory sensor required by the ECU.
The complete setup matters
Confirm the sensor, controller, installation and a compatible way to record its output. A harness alone is not a complete wideband system, and a dashboard video does not replace the requested log. If a remote logging solution does not fit your car, we can discuss an in-person dyno session.
EQUIPMENT TO REVIEW
The iWire wideband kit:
check the logging route first.
iWire’s AEM X-Series wideband with gauge and plug-and-play harness ↗ is an option to review for a compatible Subaru. Select the exact vehicle fitment and follow iWire’s installation instructions.
Support for pre–Green Speed iWire setups
I also support compatible pre–Green Speed setups using the iWire wideband kit. If you already have one, send the controller model, harness configuration, tuning software and a sample log so I can review how its data is recorded. The current-software limitation above does not mean every existing iWire installation is unsupported.
The gauge kit and the version without a gauge are different products. Confirm the complete equipment list and recording plan before purchasing either one. This product link is for equipment research; it is not a guarantee that the kit completes your remote-tuning setup.
See iWire’s product compatibility notes ↗, installation documents ↗ and my Green Speed compatibility guide.
BEFORE FLASHING
Prepare the car and the power supply.
Follow the current instructions for your exact device and vehicle. For Accessport installation and uninstallation, COBB calls for a 10–20 amp battery charger rather than a tender or jump pack. Turn off accessories and resolve other devices that may interfere with ECU communication.
Do not unplug the device or interrupt power while programming. If something fails, keep the displayed error and contact the device manufacturer or me before improvising a recovery.
Record the current device, tune-file name and any fault codes before we start. Tell me about an unknown previous tune, engine or ECU swap, or recent dealer software update.
Follow the Accessport flashing steps →
Use the COBB installation instructions ↗ for your exact device and vehicle.
DATA THAT HELPS
Send logs I can use.
I will specify the channels and operating conditions for your car. Use the requested file format and identify the tune revision and fuel used. Keep the original log file; screenshots of gauges omit the time-based data needed for review.
A useful note might read: “Revision 2, 93 octane, hesitation during the requested light-throttle test, no hardware changes.” Report symptoms honestly and stop if the car develops a misfire, leak, warning light or other abnormal behavior.
Collect data only as instructed in appropriate, controlled conditions. You do not need to invent a full-throttle test to send the first inquiry.
Accessport logging steps & platform parameters → · What is a datalog?
FUEL & THE FULL PARTS LIST
“Stage 2” is not a parts list.
Send the actual intake, MAF housing, turbo, boost-control, exhaust, injectors and pump details, plus engine internals when applicable. Package names vary between suppliers. A map for a different intake or fuel is not automatically appropriate for yours.
Choose fuel you can consistently obtain.
Tell me the pump grade and whether it is labelled AKI or RON, plus your region. If using ethanol, include the intended blend and how it will be measured. A station’s E85 label alone does not establish the ethanol content in your tank.
Flex fuel needs compatible hardware and software.
An ethanol-content sensor does not by itself create a flex-fuel calibration. The ECU strategy, sensing system and fuel-delivery hardware all need review. A legacy kit is not proof that the current tuning software supports it.
Already running a legacy flex-fuel kit?
I support compatible pre–Green Speed and legacy flex-fuel setups, including Delicious Tuning kits. Include the kit and module version, current tune, Accessport or other tuning device, software history and any planned changes in your inquiry. I review the existing combination before confirming tuning or retune scope.
Delicious Tuning distinguishes its Classic modules from its newer NexGen/FutureFlex products. These generations are not interchangeable; support for an existing legacy setup does not establish compatibility with current COBB software.
Delicious Tuning kit and module information ↗ · NexGen/FutureFlex information ↗
SAVE THIS CHECKLIST
Ready for a tuning conversation?
- Vehicle year, model, engine and transmission identified.
- Current tuning device, ECU history and tune-file name recorded.
- Complete installed and planned parts list prepared.
- Fuel grade, region and ethanol plans specified.
- Wideband and recording method confirmed where required.
- Known faults, leaks, misfires and maintenance concerns disclosed.
- Computer, cables and battery support ready for the chosen process.
- Questions about the service resolved before ordering.
A tune does not repair a mechanical problem. I may request further checks before accepting the car for calibration. Do not change the hardware or fuel midway through revisions without discussing the scope first.
ECU & TUNING PLATFORMS
Understand the system in your car.
Start with the equipment you have, or compare the routes before planning a build.
YOUR CAR / YOUR NEXT STEP
Unsure what to buy?
Ask before ordering.
Send your vehicle, existing tuning device, current parts and fuel. If you are choosing a wideband, include its model and how you intend to record it. I can help establish the requirements before you commit to a tune or equipment.