Since 2017, GM has tried to stop us from what we all like to do, turn these trucks up and go fast! The E41 ECM in the 2017 to current L5P Duramax has been long known as “locked” or “encrypted from the factory”, making it impossible to tune in the traditional sense. There are devices out on the market that piggyback the sensors under the hood, fooling the truck to build more boost, fuel pressure, and in turn, more horsepower. But if you wanted to “flash” the truck with a custom calibration, your only option was a costly ECM swap to an unlocked ECM from HP Tuners. Gone were the days of a simple EFI Live flashing like on the LML Duramax trucks. But it's not all bad news, now you have some options!
2017 and 2018 models ONLY:
2017-2023 Duramax E41 ECM Upgrade Kit (ECM-00-L5P-K)
This is the most economical and reliable option to date to unlock the E41 ECM. This device only works with the new MPVI3 however, but once you license the ecm with 6 credits, it will unlock the ecm, letting you read and write. This device can be used on multiple vehicles, making it ideal for shops or individuals with multiple trucks. Please make sure you are running the most recent Beta release for HP Tuners.
2019 to 2023 models ONLY:
As of June 2025, HP Tuners and EZ Lynk have made it available to unlock and tune directly through the OBD2 port, no additional cables or devices needed, except your MPVI3 or Auto Agent device. Whichever device you choose to flash your L5P with, when your custom tune is available, all you need to do is plug in the device to your OBD2 port, flash your file, and the process of unlocking and flashing your L5P will begin. Please make sure you are up to date with the latest firmware release for Auto Agent and the latest Beta release for HP Tuners.
If you have any questions on which option is best for your situation, please do not hesitate to call us and discuss your options with one of our sales staff 1-778-754-7090.
