EK1 Complete Tuning Guide: Start to Finish

How to get your ECU ID Reading EK1 Complete Tuning Guide: Start to Finish 11 minutes

By Tristan CherryOct 9, 2025

Before You Begin

Before you begin, we have a few basic recommendations and requirements:

General Technical Understanding: Tuning your own ECU, while generally a relatively straightforward process, is not something that we recommend you undertake if you are not at least moderately technologically literate. We don’t mean any disrespect, but this whole process will be especially daunting if the idea of something like “formatting a Micro SDHC card” seems difficult/impossible.
A Bit of Bravery: You won’t need a lot, but flashing the brains of your brand new financial investment which you also need to use to drive to work in the morning… Yeah, you’ll need a little bit of bravery.
USB-C Cable: For the purpose of updating your device you will need a reliable USB-C cable for connecting the device to your computer - so if you're thinking of using the tangled one you found in your office drawer from some 5-year-old random online purchase that came with a 0.5W charger and a paper thin USB cable... maybe reconsider?
Battery Tender: While not strictly required, having a battery tender or charger (or - as a bare minimum - a jump starter) on hand is highly recommended. A battery dying during a file load is a potential death sentence for your ECU.

Getting Started

PC Software & Device Firmware Update

Create an Account

Go to EK1tuning.com and register for an account.

Download Software

Install Software

Install the EK1TOOL software on your Windows computer.

Connect Device

Connect the EK1 to your computer using a USB-C cable.

Update Firmware

Open the EK1TOOL software.
The software will automatically detect the connected device.
Follow the on-screen prompts to update the EK1 to the latest firmware.
If it’s your first time updating your EK1, we recommend checking the box for “continue without checking version”.

Set Language (If Necessary)

The software's default language may be Korean. If so, find the language settings within the tool and change it to English.

Reading Your Vehicle's Stock ECU File

IMPORTANT NOTES

2024+ SIM2K-250: Most 2024 and newer SIM2K models will require a SIM2K Bench Cable Kit for reading and writing the ECU. At this time this is only the Facelift Sedan/Elantra and to the “Facelift 2” i30N hatchback.
CPEGD3.20.1: All Smartstream models using this ECU will require a CPEGD Bench Cable Kit for reading and writing the ECU.
Bluelink CPEGD3.20.1: The EK1 Mini and Pro models cannot interface with this ECU - it uses a new CANBUS format called CAN-FD which is only compatible with the newest EK1V3 device.

Flashing directly via the OBD2 port on these newer ECUs can result in irreversible damage. If you’re not 100% sure, confirm the required procedure for your specific model year before proceeding.

Reading the file off your ECU is not usually required for most 2.0T and 3.3TT models, however we do generally require the stock read from your ECU if you have a 1.6T model. There are some situations where we need a read from a 2.0T - for example, if you have had the fuel pump recall update and your car runs a particularly obscure software version.

That said, you may elect to take a stock ECU read if you want to have a backup of your ECU file to load back in for some reason - however there is a database of “Original ECU Files” on the ek1tuning website, so this generally isn’t required.

Reading Procedure

Connect to Vehicle

Take the EK1 to your vehicle and connect it to the OBD2 port. The device will power on.
Note for EK1 Pro: These devices will have an auto-off function that will cause the device to shut down if the blue wire is not connected to a switched 12V fuse. You can navigate into the menu structure on the device to disable the “Auto-Power” function if desired.

Read ECU ID

Navigate through the device's menu options.
Select the option to "Read" or "Get ECU Info."
Select your relevant ECU ID from the list.
The device will scan the vehicle and display your specific ECU ID.
Take of note of this for later, it will be required when ordering your tune.

Read Stock File

Select the option to "Read" the stock tune file.
The EK1 will read the entire stock map from your vehicle's ECU and save it to the microSD card. This file is typically saved with a .EKR extension.

Backup Your Stock File

Disconnect the EK1 from the car and remove the SD Card from the device.
Insert the Micro SD card into a compatible card reader and connect it to your computer.
Open the microSD card drive on your PC and navigate to the Maps folder.
Make a backup copy of this original file and save it in a safe place on your computer. This file is your factory baseline and is essential for reverting to stock.

Acquiring Tune Files

You have several options with regard to acquiring a tune file for your car. There is plenty of information elsewhere on our website about the options that we provide - and shortly our tune portal should be live allowing you to not only purchase pre-made OTS (Off-The-Shelf) tunes, but also submit custom tune requests.

Should you elect to purchase a tune file that is supplied to you in*.EKE ,*.EKP , or*.BIN format, you will need to use the EK1 tuning website to convert this to the correct*.EKR format. This process is relatively self explanatory, and generally outside of the scope of what our customers need to worry about, so you’ll have to excuse us for not giving further details here.

Transferring Files to the EK1

Disconnect and Remove SD Card: Disconnect the EK1 from the car and remove the SD Card from the device.
Connect to Computer: Insert the Micro SD card into a compatible card reader and connect it to your computer.
Navigate to Maps Folder: Open the microSD card drive on your PC and navigate to the Maps folder.
Copy Tune File: Copy your new .EKR tune file maps folder on the microSD card.
Eject Safely: Remember to safely eject the device from your computer before pulling the SD reader out.

Flashing Your ECU

CRITICAL PRE-FLASH CHECKLIST

Failure to follow these steps can lead to a bricked ECU, which is an expensive and time-consuming repair.

[OPTIONAL/RECOMMENDED] Connect a Battery Tender: Hook up your vehicle's battery to a battery tender or charger. Flashing your ECU requires the ignition to be on for an extended period of time, and some models will even run the fan at full speed while loading a file. We do say this step is optional, but be mindful that a significant a voltage drop can interrupt the process and corrupt the ECU.
[Model Dependent] Unplug The Fan: If you have a 2020 or earlier 2.0T model, or if you have a 3.3TT or 1.6T model, it’s generally a good idea to unplug your radiator fan before flashing the ECU, most (but not all) of these models will run the radiator fan full speed while accessing the ECU which can very quickly kill your battery. The connector for almost all models is a large connector under the airbox with a pair of very thick wires going into it.
Turn Off ALL Accessories: Ensure the radio, HVAC system (heating and air conditioning), interior lights, and headlights are all turned OFF.
Be Patient: Do not touch any controls in the car or disconnect the EK1 until it explicitly tells you the process is complete.

Flashing Procedure

Connect to OBD2

Plug the EK1 into your vehicle's OBD2 port.

Flash the Tune File

Navigate to the "ECU Write" menu.
Select the desired .EKR tune file you wish to flash (e.g., CT500-PB-GC-EM-V01.ekr).
Confirm your selection and begin the flashing process.
Wait patiently for the process to complete. The device will show a "Success" or "Complete" message.

Final Steps

Follow the final on-screen instructions, which typically involve turning the ignition off and on.
SIM2K-250 or SIM2K-260 owners: After flashing, and especially if going from stock to a tune, or from one tuner to another, run the “Reset Adaptive Values”.
You can now disconnect the EK1 from the OBD2 port, or you can prepare to log the vehicle straight away.

Your vehicle is now tuned. The first time you start the car, especially if you performed an adaptive reset, it may take a lot longer to crank, or may run slightly rough for a moment as the ECU calibrates to the new map. This is normal.

Troubleshooting

“Cannot find the file”

There have been several instances of MicroSD card failures. Initially you can attempt to reformat your SDHC card to FAT32 (be sure to note the folder structure on the card before doing this), however if that doesn’t work then try to replace the microSD card that comes with the device with a new, high-quality one from a reputable brand.

This error can also sometimes happen if the file was coded incorrectly (like if you have previously patched your ECU but the file you’re attempting to load is a CANBOOT format for a non-patched ECU) - After attempting to reformat the SD card, it’s worth reaching out to your tuner to confirm the file formatting.

“Incorrect file size”

There’s always a chance that the file has been coded incorrectly, or perhaps you’re attempting to load something other than a *.EKR file into the ECU.
Double-check your file is correct and reach out to your tuner.

You’ve loaded the file and your car doesn’t start

First things first, notify your tuner - after that if you pulled a backup from your ECU, load that in to get the car running again.
If you didn’t, you can download the original from the EK1 web portal and use the file converter to convert it to an *.EKR for your ECU. Some ECU models (like the SIM2K-250) will have an option to encode the*.EKR as a RECOVERY file.
The other alternative to the above, for SIM2K models, is to attempt to load a patch file to the ECU. The Patch file writes an entire file to the ECU and can correct any corruptions from either a faulty tune write or perhaps a small mistake in your ECU tune.

The file write starts but fails after a seemingly random percentage (but not 100%)

Generally, if your EK1 allows you to attempt again, you should. It’s uncommon but not impossible that you may need 2-3 goes with “trying” to write the tune before it’s successful.

If it doesn’t let you attempt to write the file again, try the above steps under point 3 to do a recovery and notify your tuner.

The file write starts but fails at 100%

This normally means the file that you’re loading in is corrupted in some way, it could be that the Checksum Correction failed when the tuner was saving the file, or it may have been corrupted during the encoding process. Either way, attempt recovery and notify your tuner.