Step-by-step guide to program a new key fob for a 2018–2023 GAC Trumpchi GS3 with the LAUNCH X431. Includes prerequisites, troubleshooting, and FAQs.

How to Add a Key to a GAC Trumpchi GS3 (2018–2023) Using the LAUNCH X431

Published: June 16, 2026

Quick Answer: Key Programming for the GAC Trumpchi GS3

Programming a new key fob for your 2018–2023 GAC Trumpchi GS3 is straightforward with the LAUNCH X431 diagnostic tool. Connect the X431 via the OBD-II port, select the correct vehicle model, navigate to the Immobilizer function, and choose "Add Key" to follow the on-screen prompts. The process takes about 10–15 minutes and requires a blank compatible transponder key. Keep in mind that the LAUNCH X431 needs an active internet connection and the licensed Immobilizer software module to perform key programming.

Before You Start: Prerequisites & Safety

I have worked with the LAUNCH X431 on dozens of Chinese-made vehicles, and the GAC Trumpchi GS3 is one of the more cooperative models when it comes to key programming. Still, proper preparation saves you from headaches halfway through the procedure. Here is what you need to check before diving in.

Check Key Compatibility

Make sure your blank key is either a genuine GAC original or a high-quality aftermarket key that supports the correct transponder type. The GS3 typically uses a 4D transponder chip (often 48 or 80), but I have also seen some models with 60‑type chips. If you are unsure, use a transponder reader to confirm the chip type or refer to your owner’s manual. A mismatch here will cause the programming to fail.

Battery Health Matters

Low voltage is the number one cause of interrupted immobilizer programming. The vehicle’s battery should read at least 12.4 volts. If the battery is weak, charge it or use a jump pack. I have lost count of how many times a seemingly failed programming session was fixed simply by connecting a battery maintainer.

Tool Preparation

Update your LAUNCH X431 software to the latest version. The immobilizer module receives frequent updates to support new vehicle models and improve stability.
Ensure the X431 tablet has a stable Wi‑Fi or mobile hotspot connection. Most immobilizer functions run through cloud servers, so no internet means no key programming.
Activate the "Immobilizer" function license if your X431 subscription requires it. Some users find this step annoying, but it takes only a minute in the settings menu.

Gather All Existing Keys

Here is a tip I always share with first‑timers: have every key you own for the GS3 ready—including the one you want to replace. Some immobilizer modules require all keys to be re‑learned together during an "Add Key" session. If you leave one key behind and later try to use it, the vehicle may not start. Better safe than stranded.

Step-by-Step: Adding a Key Using the LAUNCH X431

This procedure assumes you have a blank key with the correct transponder. If you are using a used key from another vehicle, you will need to clear its previous ID first—more on that in the FAQ. Otherwise, let us walk through the process.

Step 1: Connect the LAUNCH X431

Turn the vehicle’s ignition OFF.
Locate the OBD‑II port. On the GS3, it is generally under the dashboard on the driver’s side, near the fuse panel.
Plug the LAUNCH X431 VCI (Vehicle Communication Interface) into the port. You should see the VCI’s lights turn on.
Turn the ignition ON. Do not start the engine—just let the dashboard lights illuminate.

Step 2: Launch the Immobilizer Software

On the X431 tablet, open the LAUNCH diagnostic app.
Select Diagnosis (you may also see an "Auto Scan" option).
Choose GAC (or GAC Motor) from the brand list. If the brand list is alphabetical, scroll down until you find it.
Select Trumpchi GS3. Confirm the year range—2018 through 2023 may be grouped together.
From the system list, navigate to Immobilizer (sometimes labeled Security or Anti‑Theft).

Step 3: Enter Immobilizer Programming Mode

On the Immobilizer menu, select Key Programming.
Choose Add Key. Pay attention here—this option is different from "Erase All Keys" or "Program All Keys." If you select "Erase All Keys," you will lose all existing keys, and you will need to reprogram every key you own. Only use that function when you have lost all keys and have at least two new blanks ready.

Step 4: Security Access (Login)

The LAUNCH X431 will now attempt to retrieve your vehicle’s security PIN (a 4‑digit code) from its online server. In most cases, the tool handles this automatically. However, I have encountered situations where the connection timed out or the server could not find the code for a particular VIN. When that happens, you will see a prompt asking you to enter the security code manually.

How do you get that code? You can purchase it from a dealer or use an online transponder service (some are built into the X431’s subscription). Alternatively, the X431 may offer a "Calculated Code" function that tries to derive the PIN from the VIN. If the automatic retrieval fails, try switching your internet connection—for instance, use a mobile hotspot instead of a public Wi‑Fi network. That often solves the issue.

Step 5: Program the New Key

Follow the on‑screen instructions exactly as they appear. Typically, the software will say: "Insert the new key into the ignition and turn to ON."
Once you do that, the X431 communicates with the Body Control Module (BCM) to sync the new transponder.
After a few seconds, you should see a confirmation message: "Key Programming Successful."

If the message says "Failed," do not panic. Check the OBD connection, ensure the key is truly blank, and repeat the process from the security access step.

Step 6: Test the Keys

Turn the ignition OFF and remove the newly programmed key.
Wait about 10 seconds—this gives the BCM time to finalize the writing process.
Re‑insert the new key and start the engine. If it cranks and runs, the transponder programming worked.
Test all remote functions: lock, unlock, and trunk release. If the remote buttons do not work, you may need a separate sync procedure (see troubleshooting below).

Common Issues & Troubleshooting

Even with the best preparation, sometimes things go wrong. Here are the most frequent problems I encounter and how to fix them.

Problem: "No Communication with Immobilizer"

Fix: This almost always comes down to a weak connection. Check that the VCI plug is fully seated in the OBD‑II port. Ensure the ignition is ON (dashboard lights on). If the problem persists, update the X431 software—older versions may not fully support the GS3’s immobilizer protocol.

Problem: "Wrong Security Code"

Fix: Power cycle the X431 tablet (turn it off and back on), restart the diagnostic app, and try again. If the code is auto‑generated, change your internet connection—use a hotspot instead of Wi‑Fi, or vice versa. Sometimes the server returns an incomplete code due to packet loss.

Problem: New Key Starts Car but Remote Doesn't Work

Fix: The transponder chip is programmed correctly, but the radio frequency (RF) remote may need a separate sync. Try this manual procedure: Insert the key into the ignition, turn it to ON, press the lock and unlock buttons three times in quick succession, then turn the ignition OFF. Remove the key and test the remote. If it still does not work, the new key may have a defective RF module—try another blank.

Problem: X431 Says "Key Already Learned"

Fix: This message means the key you are trying to program is not truly blank. It may have been previously used in another vehicle. Use a transponder reader to check the chip status. If the chip already has an ID stored, you can either erase it (if your X431 has an "Unlock Key" or "Transfer Key" function) or simply use a fresh blank key.

Frequently Asked Questions (FAQ)

Can I program a key for my 2020 GAC Trumpchi GS3 without the LAUNCH X431?

No. The GAC Trumpchi GS3 requires a high‑level diagnostic scanner that can communicate with the GAC immobilizer system. Unlike older cars that have a manual "ignition on/off three times" trick, the GS3 (2018–2023) does not support any key‑less programming method. The LAUNCH X431 or a similar professional tool like Autel is the recommended solution.

Do I lose my existing keys when I add a new one?

No, as long as you select Add Key and not Erase All Keys. The Add Key function simply writes the new key’s ID into the module’s memory alongside the existing keys. Your original keys will continue to work normally.

What does the "Security Code" (PIN) mean?

The Security Code (or PIN) is a manufacturer‑specific 4‑digit number linked to your vehicle’s VIN. It acts as a password to allow access to the immobilizer programming menu. The LAUNCH X431 usually retrieves this code from a remote server automatically. If it cannot, you need to obtain the code from a dealer or a transponder data service.

How long does it take to program one key?

The actual software operation takes about 5 to 15 minutes. Add another 5 minutes for setup and final testing, so budget 20 minutes total. If you run into any issues, it may take longer.

Can I use a used key from another GS3?

It is possible but not recommended. Used keys contain a locked transponder ID that is already registered to another vehicle. The LAUNCH X431 can sometimes "unlock" a used key if you use the Transfer Key or Erase Key function first. However, using a new blank key is far more reliable and avoids potential compatibility problems.

Will this fix a dead key fob?

If your key fob is physically broken (water damage, cracked circuit board) or the transponder chip has failed, programming a new key is the only permanent fix. If the remote battery is simply dead, replace the battery—you do not need a full programming session for that.

Conclusion

Adding a key to a GAC Trumpchi GS3 (2018–2023) using the LAUNCH X431 is a job that any reasonably handy car owner can tackle with the right preparation. By ensuring your tool software is up to date, your key blank is compatible, and your vehicle battery is healthy, you can avoid most common pitfalls. The process itself is guided by the X431’s clear on‑screen instructions, and the result is a fully functional key that works for both starting the engine and remote locking.

For more details on using the LAUNCH X431 for other Chinese brands, check out our guide on similar diagnostic procedures for GAC models. And if you run into immobilizer issues you cannot solve, remember that a qualified automotive locksmith or dealer is always a safe fallback.

About the Author: Erwin Salarda is an Automotive Service Equipment Technician based in the Philippines, specializing in computerized automotive diagnostic equipment such as OBD scanners and wheel alignment systems. Since 2012, he has been actively providing technical support, equipment installation, troubleshooting, after‑sales service, and hands‑on training for automotive service equipment used by workshops and automotive professionals.

He has received specialized training from international suppliers and manufacturers, including Launch X431 in Shenzhen, China, Lawrence Engineering Company in Guangzhou, China, and 3Excel Wheel Alignment Company in Shenzhen, China. Through these trainings, he developed advanced expertise in automotive diagnostics, calibration, wheel alignment systems, and computerized automotive service technologies.

Erwin Salarda provides professional after‑sales support and technical training for automotive diagnostic and wheel alignment equipment, helping clients maximize the performance and proper use of their tools and systems. His experience covers equipment setup, software updates, calibration procedures, troubleshooting, and operational guidance for automotive workshops and service centers.

With more than a decade of experience in the automotive equipment industry, Erwin Salarda continues to support automotive businesses by delivering reliable technical expertise and practical training solutions.

For inquiries and equipment purchases, please visit https://carlifterph.com/