Mechanic Wiki: How to Program a Key on a GAC Trumpchi GA4 (2018

Learn how to program a new key for a GAC Trumpchi GA4 (2018–2022) using the LAUNCH X431 scanner. Step-by-step guide, troubleshooting tips, and FAQs.

Published: June 16, 2026

How to Program a Key on a GAC Trumpchi GA4 (2018–2022) with LAUNCH X431

Quick Answer: Key Programming for the GAC Trumpchi GA4

Programming a new key for a GAC Trumpchi GA4 (2018–2022) using the LAUNCH X431 requires the immobilizer (IMMO) function. The standard process involves connecting the X431, selecting the correct vehicle model, navigating to "IMMO" > "Key Programming" > "Add New Key," and following the on-screen prompts. You will need the vehicle's 4-digit PIN code (often obtainable from the X431 online database or a dealer). The process takes approximately 5–10 minutes per key. Always ensure the original key is present and the vehicle battery is fully charged.

Preparation and Prerequisites

Before diving into the programming procedure, let’s make sure you have everything you need. I’ve seen many DIYers get halfway through and realize they’re missing a critical piece – don’t let that be you.

Tool Required:
A LAUNCH X431 diagnostic tablet – any of the Pro, V, or PAD series will work, as long as it has the latest software installed. Make sure the “GAC” or “Trumpchi” vehicle package is loaded, especially the IMMO (immobilizer) module. The X431 checks for updates when you first connect to Wi-Fi, so do that before starting for a smoother experience.

Vehicle Condition:
The GA4 must be parked in a safe, well-lit area. Check the battery voltage – it should read between 12.5 and 13.5 volts. A low battery is one of the most common reasons key programming fails, because the immobilizer system draws a surprising amount of power during the learning process. If in doubt, connect a battery maintainer. Keep the ignition in the OFF position until instructed to turn it ON.

Key Information:

Original Working Key: You absolutely need at least one working original key to add a new one with the “Add New Key” function. Without it, you’ll have to use “Erase and Program All Keys,” which wipes all existing keys.
Blank Key: Purchase a compatible uncut blank key that matches the GA4’s transponder frequency. Most aftermarket blanks work fine, but I recommend sticking with OEM or high-quality clones.
PIN Code: The 4-digit security PIN is your golden ticket. The LAUNCH X431 usually retrieves it automatically via its online database, but having the code written down from the vehicle’s documents or a dealer is a good backup.

Step-by-Step Programming Process

Follow these steps in order. The exact screen labels may vary slightly depending on your X431 model, but the logic remains consistent.

Step 1: Connect the LAUNCH X431

Turn the ignition to the OFF position and remove the key.
Locate the OBD-II port under the dashboard on the driver’s side. On the GA4, it’s usually right above the hood release lever.
Plug the X431’s main diagnostic cable firmly into the OBD-II port. You should hear a click.
Turn on the X431 tablet. The screen will light up and begin initializing.

Step 2: Establish Vehicle Communication

On the home screen, tap Diagnostics.
Scroll down and select GAC or Trumpchi from the brand list. If you see “Trumpchi,” choose it.
The X431 will attempt an automatic VIN scan. Let it complete – this usually takes 30–60 seconds. If it fails (which can happen with some imported models), manually select the GA3S or GA4 platform. Look for a sub-menu that matches your vehicle year (2018–2022).
Confirm the displayed vehicle information – VIN, engine type, and year – and tap OK.

Step 3: Navigate to the IMMO Function

From the system menu, select Immobilizer (IMMO) or Anti-Theft System. I’ve found that “IMMO” is the most common label.
The X431 will read the immobilizer module. When you see “System Identified,” you’re ready to proceed.

Step 4: Perform Key Programming

Inside the IMMO menu, select Key Programming.
You’ll be asked to choose between two options:
- Add New Key – This preserves all existing keys and adds the new one. Choose this option if you still have your original key.
- Erase and Program All Keys – This deletes every key from the vehicle’s memory and then programs all keys (including your original) from scratch. Use this if you’ve lost a key or the key memory is full.
The X431 will then request the 4-digit Security PIN. In most cases, it retrieves this automatically. If prompted, enter it manually using the on-screen keypad.
Follow the on-screen instructions exactly. Typically, the X431 will ask you to:
1. Turn the ignition OFF.
2. Remove the original key.
3. Insert the new blank key into the ignition.
4. Turn the ignition ON (dashboard lights up, but do not crank the engine).
The tablet will send the programming command. After a few seconds, you’ll see a success message: “Key Added Successfully.”

Step 5: Verify the New Key

Disconnect the X431 from the OBD-II port.
Test the new key: Insert it into the ignition and turn to the ON position. The dashboard should illuminate normally – no anti-theft warning light or flashing immobilizer icon. Next, test the remote functions: lock, unlock, and trunk release. If the remote doesn’t work, you may need to run a separate “Remote Key Programming” under the IMMO menu (some GA4 models pair the remote separately).

Troubleshooting Common Issues

Key programming doesn’t always go flawlessly. Here are the most common hiccups and how to fix them.

Problem	Likely Cause	Solution
X431 cannot connect	Bad cable connection; vehicle not recognized.	Inspect OBD cable pins for damage. Try selecting a different vehicle profile (e.g., GA3S). Ensure X431 software is fully updated.
Error: “Communication Failure”	Low battery voltage; wireless interference.	Connect a battery charger. Move the vehicle away from other electronics (like fluorescent lights or EV chargers). Restart the X431.
“Key Already Exists” or “Limit Reached”	The vehicle’s key memory is full (max 4–5 keys).	Use the Erase All Keys function first, then add all keys (including your original) one by one.
PIN Code request fails	X431 database may not have the PIN for a non-standard vehicle.	Try the “Auto Read PIN” option. If it still fails, you’ll need to obtain the code from a GAC dealer or a locksmith.
New key works in ignition but remote doesn’t	Remote code not paired, or remote battery is dead.	Re-run “Remote Key Programming” (separate from IMMO). Replace the key fob battery (usually a CR2032 coin cell).

Frequently Asked Questions (FAQ)

Can I program a key for the GAC Trumpchi GA4 without a working key?
No, for the standard “Add New Key” process, you need at least one working original key. If you’ve lost all keys, you can use the Erase and Program All Keys function, but this still requires the immobilizer PIN code. If the X431 cannot retrieve the PIN automatically, you’ll likely need to contact a dealer or specialized locksmith.

Can I use any OBD2 scanner to program a key for a GA4?
No. A generic OBD2 code reader can only read and clear engine codes – it cannot program keys. You need a professional-level diagnostic tool with IMMO (immobilizer) capability, such as the LAUNCH X431, Autel MaxiCOM, or a dealer-level tool.

Will programming a new key with the X431 erase my existing keys?
Only if you select the Erase and Program All Keys option. The Add New Key function preserves all existing programmed keys while adding the new one – a safer and faster choice if you still have your original key.

How many keys can the GAC Trumpchi GA4 store?
The GA4’s immobilizer system can typically store up to 4 or 5 keys. Once you reach that limit, you must erase all keys and reprogram them from scratch. I recommend keeping the count to three keys maximum to leave room for future replacements.

My X431 says “Operation Failed.” What should I do?
First, check the battery voltage – it must be above 12V while the ignition is on. Second, ensure the new key blank is compatible (it must have a functioning transponder chip for the GA4’s frequency). Third, try the entire process again from the beginning. If it fails a second time, update the X431 software and try once more. If it still fails, the immobilizer module itself may have an issue – consider professional diagnostics.

Is it safe to drive after programming?
Yes, absolutely. Once the new key is successfully programmed, the immobilizer recognizes it as a trusted key, and the engine will start normally. The car’s security system remains fully intact.

How long does the entire process take?
From connecting the X431 to testing the final key, expect about 10–20 minutes for a first-time user. Experienced technicians can complete it in under 5 minutes. Take your time and don’t rush the on-screen prompts.

Do I need to update my LAUNCH X431 software before programming?
Yes – always update the X431 to the latest firmware and software. This ensures compatibility with the latest GAC Trumpchi models and avoids common connection errors. I’ve seen many failed procedures that were fixed with a simple software update.

For more detailed walkthroughs, check out our guide on [link to related guide on GAC Trumpchi diagnostics] or [link to another related article on using LAUNCH X431 for key programming]. These resources cover additional vehicle models and advanced IMMO functions.

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/