// Install guides
HP TUNERS UNLOCK, STOCK READ & TUNE LOAD — 17-23 DURAMAX L5P
Install the software below before you do anything else on the truck. Never disconnect during a write. The unlock flash takes 9 minutes and is followed by a 6-minute flash of your stock file; leave the truck, the cable and the laptop alone until it says Write completed.
Unlocking the E41 ECM on a 2017–2023 Chevy/GMC 2500/3500 L5P Duramax with the HP Tuners unlock cable, taking the stock read and info log, sending them in so your tunes can be built, and loading the tunes when they arrive. Watch the video first: it walks through installing the HP Tuner in an L5P at home. Park somewhere safe and out of the way, preferably a garage. The whole process can take a couple of hours, and you need internet access for all of it. If your ECM was already unlocked, skip the unlock cable steps and start at the read.
Steps
1 Download and install .NET Windows Desktop Runtime 8
The unlock pages still name version 6, but the current VCM Suite needs 8.
More on this step →2 Download and install the latest VCM Suite beta
3 Find the unlock cable that came with your package
You need it if this is your first flash and the ECM has never been unlocked. If it was unlocked before, skip ahead to opening VCM Editor.
4 Locate the main fuse panel under the hood, driver side
If you are also installing an unlocked TCM, now is a good time to fit it: on 2017 trucks it sits on the fan shroud, on 2018–2019 on the firewall.
5 2017–2019 trucks: fit the jumper in ECM fuse 57
Remove the factory 3-prong fuse from position 57. Fit the unlock cable jumper with the white wire closest to the firewall, leaving an open slot toward the front of the truck. That open slot is the TCM side of the fuse and is not used for the unlock.
6 2020–2023 trucks: fit the jumper in fuse 78
Remove fuse 78. Fit the unlock jumper in its place with the white wire facing the driver side, which leaves the red wire toward the engine.
7 L5D trucks: fit the jumper in fuse 78
Remove fuse 78 and fit the unlock cable jumper with the white wire closest to the firewall.
8 Route the cable into the cab and plug it into the MPVI
With the jumper secure in the fuse box, bring the unlock cable, your computer and the MPVI3 into the cab. The unlock cable plugs directly into the front of the MPVI3.
9 Open VCM Editor, connect the MPVI, and resync it
Connect the MPVI3 to the computer first, then to the truck's OBD2 port. Validate it with Help > Resync Interface.
10 Read the ECM
Make sure no other files are open in VCM Editor, then click the green Read arrow in the top centre. Turn the ignition on first: on 17–19 trucks turn the key two clicks forward; on 20+ trucks push and hold the start button for 8 seconds to cycle the ignition on. Select the modules you want to read.
11 Click OK on the "Upgrade Required" message
It says the module will be upgraded during the first write and to leave the unlock cable installed until then. If you do not get this message and the ECM has not been unlocked before, check the cable and its connections.
12 Save the stock read to your desktop
Name it with your name, model year and "stock read".
If you bought credits from us, click Help at the top and Resync Interface before going on.
13 Click the red Write arrow and license the controller
Keep the read file open and the unlock cable installed. Since this is the first flash, choose Specific under licensing and click Yes. The ECM takes 8 credits and the TCM 4. If the truck has been flashed before, skip the licensing.
14 Choose Write Entire and click Write
15 Wait through the unlock and the stock flash
The unlock portion takes 9 minutes. When it finishes click OK, but do not disconnect anything: VCM Editor now flashes your stock file back into the ECM, which takes 6 more minutes.
16 On Write complete, key off, remove the cable, refit the fuse
The GM E41 controller is now unlocked. The truck is still stock, and you will not need the unlock cable again.
17 Take the info log
Key the truck on. With VCM Scanner or VCM Editor open, click the white "i" with the blue circle around it. In the smaller window that opens, click the "i" again. Once the data has populated, save the document with your name and VIN.
18 Email the stock read and info log
Send support@thedieseltechs.com your name, order number, stock file and info log. Allow 1 to 2 business days for your custom calibrations. A support and remote tuning appointment can be booked ahead for same-day service. You can drive the truck in the meantime.
19 When your tunes arrive, open the tune file in VCM Editor
Click Open in the top left corner, find the tune file you want to load, and open it.
20 Write the tune to the truck
With the tune file open, click the red Write arrow at the top. In the writing box choose Write Entire and click Write.
21 Wait for Write completed, then cycle the ignition
A full flash takes around 8 minutes, a calibration-only flash around a minute. As soon as it says Write completed, cycle the ignition and the tune is loaded.