HOW TO FLASH 17-26 L5P USING HP TUNERS

File Loading & Test Instructions

HP Tuners Setup

  1. Open HP Tuners VCM Editor (Beta).

  2. Load the file we sent you.

  3. Make sure you have already purchased credits for your VIN.

  4. Connect your MPVI interface.

  5. Resync the interface so the credits appear on the device.

    • Go to Help → Resync Interface.

Once credits are confirmed on the interface, you are ready to flash the truck.

Flashing the File

  1. Write the file to the truck.

  2. Select Write Entire — DO NOT select Write Calibration Only.

  3. Once the file finishes loading, clear all codes.

Important

Ignition must be in the RUN position with the engine OFF during the flashing process.

L5P Duramax Ignition Instructions

2017–2019 L5P (Key Start)

  1. Insert the key into the ignition.

  2. Turn the key to the RUN position.

  3. Do NOT start the engine.

  4. Leave the key in RUN during the entire flashing process.

2020+ L5P (Push Start)

The truck must be in RUN / Service Mode before flashing.

  1. Do NOT press the brake pedal.

  2. Press the push-start button once.

  3. Press it again until the dash is fully on and the green light indicator is on.

  4. Do not start the engine.

This keeps all modules awake during programming.

Testing the File

  1. Disconnect one of the EGR sensors.

  2. Check for codes.

If everything looks good, let us know and we will send the modified power file.

If a Code is Still Present

  1. Load the file again.

  2. Perform another Write Entire.

  3. Clear codes again after the flash finishes.

  4. Make sure ignition is in the RUN position with engine OFF.