Let's talk about "locked" GPEC PCMs.
You can check our or video, or continue reading below.
GPEC stands for Global Powertrain Engine Controller, and it refers to a family of PCMs, or ECUs, used across a wide range of Dodge, Ram, Jeep, Chrysler, and Fiat vehicles.
These ECUs were originally manufactured under the Continental name and later transitioned to Vitesco.
There are several different versions of the GPEC ECU family. In this guide, we’ll focus on the GPEC2A, but AutoTuner also supports GPEC2, GPEC3, GPEC4, and GPEC4LM as of the time of writing.
One thing that’s common across many of these ECUs is that they’re locked from the factory. That means you can’t simply connect through the vehicle’s OBD port and begin reading and writing tuning files.
First, the ECU needs to be unlocked in Boot Mode with an OBD Patch.
If your shop has an AutoTuner Tool, you can perform that entire process in-house.
Instead of sending the ECU out, waiting for it to come back, and then finishing the tuning job, you can open it, unlock it, reseal it, and potentially have the vehicle back to your customer the same day.
Of course, you or your customer can always send the ECU directly to us and we’ll perform the unlock for you. But if you’re equipped and comfortable doing this type of work in your own shop, AutoTuner gives you the ability to handle the entire process yourself with no additional unlock fee from us.
Once the ECU is unlocked, you can read and write it through the OBD port using the AutoTuner Tool.
And if your customer uses a handheld flashing solution from another tuning company, that’s fine too. The unlock itself is not designed to lock them into the AutoTuner ecosystem.
For this GPEC2A, the process requires opening the ECU case, connecting directly to the ECU harness, and making contact with the boot point using the AutoTuner test probe.
Once connected in Boot Mode, you can:
- Read a complete backup of the ECU
- Write a modified file directly in Boot Mode
- Apply the AutoTuner OBD patch
Applying the OBD patch enables future reading and writing directly through the vehicle’s OBD port.
What You’ll Need
Everything required to make the electronic connection is included with your AutoTuner Tool.
AutoTuner Equipment
You’ll need:
- AutoTuner Tool
- Power Adapter
- Universal Box
- Black Universal Harness
- Probe Positioner
- Test Probe
- Banana Cable
Tools for Opening and Resealing the ECU
You’ll also need a few basic tools:
- A small flat-head screwdriver or pry tool
- A larger flat-head screwdriver or pry tool
- A set of pliers
- A small block that can lift the ECU roughly three inches off the work surface
- A quality sealant, such as Loctite 5810A liquid gasket, for resealing the ECU
Start by Checking the Compatibility Guide
Before opening any ECU, always check the latest AutoTuner compatibility information first.
AutoTuner is constantly adding new protocols and connection methods, so an ECU that previously required Boot Mode may now be supported through OBD or Bench instead.
There’s no reason to open an ECU if you don’t have to.
Connect your AutoTuner Tool to your PC using the USB cable, open the AutoTuner software, search for the ECU or protocol, and review the available methods.
If Boot Mode is still required, you’re ready to move on. You can also use this opportunity to review the instructions, which will often include the physical location of the ECU in the vehicle.
You'll want to keep the application open on the instructions. We'll need them later.
Opening the ECU
Start with the ECU on a clean, stable work surface.
The first step is to release the metal tabs that hold the case together.
Carefully pry each tab upward and fold it slightly out of the way.
Once all of the tabs are released, begin at one corner on the short side of the ECU.
Insert the smaller screwdriver between the two halves of the case and gently begin separating them.
Take your time here.
You do not want to excessively bend the case, and you definitely do not want to push the tool deeply inside the ECU.
In some areas, there is less than a centimeter between the edge of the case and the circuit board, so keep the tool shallow and work only along the seam.
Once you’ve lifted the case enough with the smaller tool, insert the larger screwdriver or pry tool and gently twist it to lift the lid further.
Work your way around the case until the seal has released and you should be able to remove the cover by carefully pulling it away from the ECU.
You now have access to the circuit board.
Setting Up the AutoTuner Tool
Now lets jump back into the AutoTuner software on the PC, which should still be on the instruction pages.
Additionally, connect the AutoTuner power supply and plug it into a standard outlet.
Scroll down and the AutoTuner software will show you:
- Which ECU pins need to be connected
- How to configure the Universal Box
- Where the boot point is located on the circuit board
For this GPEC2A, six pins on the light-grey ECU connector need to be connected using the black Universal Harness.
Once those connections are made, carefully flip the ECU over and place it on a small block.
The goal is to raise the ECU enough that you can access the circuit board while making sure the harness pins and connections are not disturbed. We used a 3D printed 3x3x3 inch box, but something simple like a roll of tape would probably work fine.
Next, connect the Universal Harness to the Universal Box using the purple and white connectors.
Connect the banana cable to the test probe, then mount the probe in the probe positioner.
Connect the other end of the banana cable to the H1 port on the Universal Box.
You’re now ready to locate the boot point.
Connecting to the ECU in Boot Mode
Use the AutoTuner connection instructions to locate the correct boot pad on the ECU circuit board.
There may be some of the yellow clay like material blocking the pin. Just scratch it away with your fingernail so you can see the pins.
Position the test probe directly on the indicated point and make sure you have solid contact.
Keep in mind, the pin is small. If you don't have the best eyes, you may need a magnifying glass. I like to count the similar components and pads in the area to ensure I'm connected to the correct point.
Before continuing, verify the entire setup.
Make sure:
- The harness connections match the AutoTuner diagram
- The Universal Box is configured correctly
- The probe is touching the correct boot point
- Nothing has moved while positioning the ECU
Once everything looks correct, click Identify in the AutoTuner software.
AutoTuner will communicate directly with the ECU and verify whether you’ve selected the correct protocol.
If the ECU does not identify, go back through the basics before changing anything else.
Verify the ECU type and selected protocol, check the harness connections, confirm the Universal Box setup, and make sure the boot probe is making solid contact with the correct point.
Backing Up and Unlocking the ECU
Whenever you’re working with an ECU for the first time, it’s good practice to create a complete backup before making any changes.
That gives you a copy of the original ECU contents before anything is modified.
In this case, however, we’re going to apply the OBD patch.
When you select the OBD patch option, AutoTuner automatically performs the required backup first and then programs the ECU with the patch.
Once the process is complete, the ECU is unlocked for OBD reading and writing.
At this point, you have two options.
If you already have a modified calibration file ready, you can write it directly to the ECU while you’re still connected in Boot Mode.
Or you can reseal the ECU, reinstall it in the vehicle, and perform future flashing through the OBD port.
That’s one of the biggest advantages for your shop.
You handle the unlock once, in-house, and from that point forward the ECU can be serviced much more easily through OBD.
And again, this is not a proprietary unlock designed to force the customer to stay within the AutoTuner ecosystem.
You can continue reading and writing the ECU using your AutoTuner Tool, but the unlocked ECU can also be used with many of the handheld flashing solutions your customers may already be using.
Resealing the ECU
Once the unlock is complete, disconnect your equipment and prepare to reseal the ECU.
Before applying sealant, inspect the lid and make sure it is still flat.
If the edges were slightly bent while opening the case, carefully straighten them so the lid sits properly against the ECU housing.
Next, apply a small, continuous bead of sealant around the sealing surface of the ECU.
You do not need a large amount. The goal is simply to create a consistent seal around the entire perimeter.
Reinstall the lid and press it firmly into position.
Then use your pliers to carefully bend each of the metal retaining tabs back down into place.
Finally, inspect the entire perimeter of the ECU.
Make sure:
- The lid is sitting flat
- All retaining tabs are secure
- The sealant is continuous
- There are no obvious gaps in the case
Once the ECU is properly sealed, the job is complete.
Ready for OBD Flashing
You’ve now unlocked the GPEC2A ECU in-house and enabled OBD reading and writing.
Reinstall the ECU in the vehicle, connect through the OBD port, and you’re ready to continue tuning.
For shops that regularly work with Dodge, Ram, Jeep, Chrysler, and Fiat vehicles, being able to perform these unlocks in-house can eliminate shipping delays, reduce turnaround time, and give you more control over the entire tuning process. And best of all, there's no unlock charge from us. It's yours free to use, all without any subscriptions either.
As always, if you need assistance, our support team is here to help. Send us an email at info@autotuner.com or submit a support ticket and we’ll assist.
