GAC Vehicle Programming 

How to Program a Smart Key on a GAC Trumpchi GS4 (2019–2023) Using LAUNCH X431

• June 17, 2026
Learn to program a new smart key for your 2019-2023 GAC Trumpchi GS4 with a LAUNCH X431. Step-by-step guide, tools needed, and troubleshooting tips.

Published: June 16, 2026 | Last Updated: June 16, 2026

Quick Answer: Yes, you can program a new smart key for a 2019–2023 GAC Trumpchi GS4 yourself using a LAUNCH X431 diagnostic tool. The full process takes about 15–25 minutes and requires a working existing key, a new compatible blank key, and an updated X431. You do not need to visit a dealer for a simple key addition — just follow the immobilizer programming steps in your X431’s GAC/Trumpchi software.

Before You Start: What You’ll Need

Programming a smart key on a GAC Trumpchi GS4 isn’t magic, but it does require the right tools and a bit of preparation. Let’s make sure you have everything ready before you dive in.

Tools and Materials Checklist

  • LAUNCH X431 diagnostic tool — any model that supports GAC/Trumpchi immobilizer programming (Pro, V, PAD V, or higher). Make sure the software is updated to the latest version.
  • Existing working smart key — you must have at least one key that already starts and locks/unlocks the vehicle.
  • New blank smart key — must be a compatible blank. The OEM part number is A670900100, and the FCC ID is typically T/A-001. Aftermarket blanks from brands like Xhorse or Autel often work, but verify compatibility with your X431’s database.
  • Stable internet connection on the X431 — required for software updates and online authorization during the initial setup.
  • Vehicle battery in good condition — a weak battery (below 12.4V) can interrupt programming and damage the immobilizer system. Charge it or use a battery maintainer if needed.

Important Safety Warnings

First, never interrupt the programming process once it starts. A power loss — either from the vehicle battery or the X431 — can corrupt the immobilizer ECU, leading to a costly repair. Second, keep your new key fob inside the vehicle for push-to-start models; the transponder needs to be near the ignition coil area. Finally, remember that the “Add Key” procedure will erase any keys not present during the session. Always include your existing working key.

Step 1: Connect and Initialize the LAUNCH X431

Start by turning on your LAUNCH X431 and letting it fully boot up. Plug the VCI (Vehicle Communication Interface) into the OBD-II port under the driver’s side dashboard. For the GS4, the port is typically right above the footwell, near the hood release lever.

Now, turn the ignition ON without starting the engine. On push-to-start models, press the start button once without touching the brake pedal. The dashboard lights should illuminate.

Launch the diagnostic app on the X431. Navigate to GAC → Trumpchi → GS4. The tool will automatically read the vehicle’s VIN and confirm the model year. If the X431 asks you to select the year manually, choose the correct range (2019–2023). The software will then load the appropriate diagnostic modules.

If you’re new to the X431 interface, check out our [link to related guide on setting up the LAUNCH X431 for the first time] for a walkthrough of the home screen and VCI pairing.

Step 2: Navigate to Immobilizer Programming

From the main diagnostic menu, select Immobilizer or Anti-Theft System — the wording depends on your software version. The X431 will attempt to communicate with the vehicle’s immobilizer module. You should see a screen showing system information like the immobilizer part number and software version.

If you get a “No Communication” error, double-check that the ignition is ON and the VCI is properly connected. Sometimes restarting the diagnostic session or turning the ignition off and on again resolves it.

Once communication is confirmed, choose Key Programming or Add Key from the sub-menu. Do not select “All Keys Lost” unless you have zero working keys — that mode requires a security code from a dealer (more on that in the FAQ).

Step 3: Initiate the “Add Key” Procedure

The X431 will display a warning: “All keys will be reset. Continue?” This means the tool will clear the immobilizer memory and then re-learn all keys you program during this session. Click Confirm.

Now, the tool will ask you to insert your existing working key into the ignition switch (or place it near the start button for push-to-start models). Follow the on-screen prompt: turn the ignition OFF, then back ON. For push-to-start, press the start button twice. The X431 reads the transponder ID of your existing key and stores it.

This step usually takes about 5 seconds. The tool will confirm that the existing key has been successfully recognized.

Step 4: Program the New Smart Key

The next prompt says: “Please place the new key near the ignition coil.” Take your new blank smart key and hold it within 1–2 inches of the ignition switch or the push-to-start button. Do not press any buttons on the new key during this step — the X431 only needs to read the transponder chip inside.

Wait for the X431 to confirm. A success message typically appears after 10–20 seconds. If the tool asks you to program a second new key, repeat the same process. If you only have one new key, just select “Next” or “Confirm” to skip.

Note: Some LAUNCH X431 models may ask you to turn the ignition off and on again between key reads. Simply follow the on-screen instructions exactly.

Step 5: Verify Key Functionality

When the tool displays “Key Programming Successful”, turn off the ignition and remove your keys. Test every function of both the old and new keys:

  • Engine start — the engine should crank and run smoothly.
  • Door lock/unlock — press the lock button on both fobs.
  • Trunk release — if equipped.
  • Remote start — if your GS4 has this feature.

If the engine starts but the remote lock/unlock functions don’t work, don’t panic — you likely need to perform a separate remote key programming step (see Step 6).

Step 6: Program Remote Control Functions (If Needed)

On many LAUNCH X431 models, the immobilizer programming only teaches the transponder chip. The remote keyless entry (RKE) codes are learned in a separate procedure. Here’s how:

  1. From the same immobilizer menu, select Remote Key Programming or RKE Learn.
  2. Follow the on-screen prompt: press any button (lock or unlock) on the new key fob.
  3. The tool will learn the remote code — this usually takes about 5 seconds.
  4. The X431 will confirm success. Exit the menu and test all remote functions again.

If the remote still doesn’t work, try replacing the key fob battery (CR2032) and reattempt the RKE learn process. Sometimes the BCM (Body Control Module) antenna is located near the overhead console or driver’s footwell — holding the fob closer to that area can help.

Troubleshooting Common Issues

Here’s a quick reference table for the most frequent problems you might encounter during programming:

Issue Likely Cause Solution
X431 cannot communicate with immobilizer Ignition not ON, or wrong vehicle selected Turn ignition ON, verify model/year, restart diagnostic session
“Key Already Learned” error The new key was previously programmed to another vehicle The key is used and cannot be reprogrammed. Purchase a new blank
Engine starts but doors don’t lock/unlock Remote codes not learned Perform separate RKE programming (Step 6)
Tool freezes during programming Software glitch or weak vehicle battery Disconnect tool, restart vehicle, update X431 software, try again
“Security Code Required” message You selected “All Keys Lost” or the vehicle has enhanced security (late 2022–2023 models) Obtain security code from a GAC dealer (see FAQ)
Programming completes but new key doesn’t start engine Incorrect key type (OEM vs aftermarket) Ensure key is compatible with Trumpchi immobilizer protocol. Use OEM part A670900100 if possible
Existing key stops working after programming Was not included in the programming session Repeat “Add Key” procedure with both keys present

Post-Programming Checks

After everything seems to work, perform these final checks to ensure 100% reliability:

  • Start the engine at least three times with each key. If the immobilizer light stays on or the engine stalls, the key wasn’t fully learned.
  • Test remote range: lock and unlock the doors from about 10–15 meters away.
  • Check the dashboard for any warning lights. The immobilizer indicator (usually a car with a key icon) should turn off after starting.
  • If your GS4 has passive keyless entry (smart entry), walk away from the car with the key fob, then approach again. The doors should automatically unlock.

Context: Understanding Smart Key Programming on the GS4

Why DIY Programming Works

The 2019–2023 GAC Trumpchi GS4 uses a rolling-code transponder system built on Texas Instruments technology. The LAUNCH X431 communicates directly with the immobilizer module via the vehicle’s CAN bus — the same protocol dealership diagnostic tools use. That’s why a well-equipped aftermarket scanner can perform the same key-add procedure as a dealer’s SDD or GAC-specific tool.

Software Versions That Support This

Not every LAUNCH X431 model can do this job out of the box. Here’s what you need:

  • X431 Pro — requires the GAC software package v12.0 or later.
  • X431 V+ — needs the immobilizer module v3.5.
  • X431 PAD V — requires the GAC Trumpchi expansion pack v7.2.
  • X431 HD III — limited support. Check compatibility before purchasing.

If your X431 is older or hasn’t been updated in a while, connect to Wi-Fi and run a full firmware and database update before starting.

When You Absolutely Need a Dealer

  • All keys lost: If you have zero working keys, the immobilizer module is locked and requires a 4-digit security code (PIN). Only a GAC dealer (or a locksmith with a subscription to the GAC security database) can generate this code after verifying ownership.
  • ECU or BCM replacement: Installing a new engine control unit or body control module often needs online coding that the X431 cannot perform. Dealer-level tools or specialist locksmith equipment may be required.

Frequently Asked Questions

Can I program a used smart key from another GS4?

No. Smart keys are “married” to a single vehicle’s immobilizer. A used key will show as “Already Learned” and cannot be reprogrammed. You must buy a new, unprogrammed blank.

How many keys can I store in the GS4?

The vehicle can store up to 4 smart keys. If you try to add a fifth, the oldest key in memory will be automatically erased. Plan accordingly if you have multiple drivers.

Will programming erase my existing key?

Only if you do not include it in the “Add Key” process. Always have your existing working key present and follow the on-screen prompts to keep it in memory.

Do I need a special key blank?

Yes. The GS4 uses a transponder-based smart key with OEM part number A670900100. Third-party blanks (e.g., from Autel or Xhorse) often work but must be compatible with the Trumpchi immobilizer protocol. Check with your key supplier or the X431’s compatibility list before buying.

What if the X431 asks for a security code?

This occurs when you select “All Keys Lost” mode or if your vehicle has a high-security immobilizer variant (late 2022–2023 models). You can obtain the 4-digit security code from a GAC dealership — you’ll need to prove ownership with registration and ID. A locksmith with access to the GAC security server can also retrieve it.

Can I use a different diagnostic tool?

Yes, but only tools that explicitly support GAC/Trumpchi immobilizer programming. The Autel IM508, Xtool X100 PAD, and some ThinkCar tools are known to work. Generic OBD-II scanners cannot access the immobilizer module at all.

How long does the process take?

For a single key addition, expect about 15–20 minutes. If you have two new keys, add another 5–10 minutes. Most of the time is spent waiting for the X431 to communicate with each key.

What happens if the battery dies during programming?

You may permanently damage the ECU or immobilizer module. Always ensure the vehicle battery is fully charged and, if possible, keep the X431 connected to an external power source.

My new key works but the remote doesn’t — did I miss a step?

Yes. The LAUNCH X431 often requires a separate “Remote Key Learning” step (see Step 6). If that fails, check the key fob battery (CR2032) and try again with the key fob very close to the BCM antenna (usually near the overhead console or driver’s side footwell).

Do I need to update the X431 firmware before starting?

Yes. An outdated X431 may not have the correct protocol for 2019–2023 GS4 models. Connect to Wi-Fi and update both the system firmware and the GAC vehicle database before beginning. If the update fails, contact LAUNCH support for assistance.

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/

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