How to Read and Enter a PIN Code for GAC Trumpchi Key Programming with LAUNCH X431

Last Updated: June 16, 2026

Quick Answer: How to Read and Enter a PIN Code for GAC Trumpchi Key Programming

To program a new key for a GAC Trumpchi using a LAUNCH X431 diagnostic tool, you must first retrieve the vehicle’s unique 4‑digit PIN (security code) and then enter it correctly during the immobilizer programming process. The PIN can be read directly from the ECU by the X431, or calculated from the 17‑digit VIN using the tool’s built‑in function or an online calculator. After connecting the scanner and selecting the correct model, navigate to the immobilizer menu, choose “Read PIN Code” or “Key Programming,” input the code when prompted, and follow the on‑screen steps to program the new key. Always ensure your X431 software is up‑to‑date for compatibility with newer Trumpchi models.

Introduction to GAC Trumpchi Key Programming with LAUNCH X431

If you’re a locksmith, an automotive technician, or a DIY car owner who needs to replace a lost or broken key for a GAC Trumpchi, you’ve likely encountered the LAUNCH X431 series of diagnostic tools. These scanners are widely regarded as powerful, affordable options for immobilizer and key programming on many Asian vehicles, including GAC Trumpchi models like the GS4, GS5, GS8, GA6, and others.

However, one step consistently trips up even experienced users: reading and entering the PIN code. Without this four‑digit security number, the programming process will fail, and you may lock out the immobilizer system temporarily. In this guide, I’ll walk you through exactly how to obtain that PIN using your X431, enter it correctly, and avoid the most common pitfalls. Whether you’re using a LAUNCH X431 PRO, X431 V+, X431 PAD VII, or an older model, the core procedure remains the same.

Understanding the Role of the PIN Code in Key Programming

What Is a PIN Code for GAC Trumpchi?

A PIN code (also called a security code or immobilizer code) is a unique 4‑digit number assigned to the vehicle’s engine control unit (ECU) or body control module (BCM) at the factory. This code acts as a password that must be provided before the immobilizer system will accept a new key. Without it, the transponder chip inside the key will not be recognized, and the engine will not start.

For GAC Trumpchi vehicles, the PIN is not printed anywhere on the key or in the owner’s manual. It is stored in the ECU and can only be retrieved via a compatible scan tool or by contacting the dealer with proof of ownership.

Why Does the LAUNCH X431 Require a PIN?

When you use the X431’s immobilizer function to add a new key, the tool communicates with the vehicle’s ECU and sends a command to learn the new transponder. For security reasons, the ECU demands the correct PIN before it allows this learning procedure. Think of it as unlocking a safe: you need the combination before you can change the contents inside. The LAUNCH X431 acts as the intermediary, passing the PIN you enter to the ECU.

Differences Between PIN Code, Security Code, and Immobilizer Code

You may see these terms used interchangeably in different software menus or forum posts. Technically, they all refer to the same thing: the 4‑digit number required to authorize key programming. Some older GAC Trumpchi models also use a 5‑digit code, but the vast majority require 4 digits. If your X431 prompts for an “Immobilizer Code” or “Security Code,” simply enter the 4‑digit PIN you retrieved.

Step-by-Step Guide: Reading and Entering the PIN Code

1. Preparation

Before you begin, make sure you have everything ready:

• Required tools: A LAUNCH X431 scanner with GAC Trumpchi software installed. Any X431 series works (PRO, V+, PAD, etc.) as long as the software is up‑to‑date.
• Vehicle key: The original key should be present if available (for “add key” procedure). If you’re programming a brand‑new blank key, ensure it has the correct transponder chip (e.g., 4D‑60, 4D‑67, or T5 depending on the model).
• OBD‑II extension cable: Useful if the diagnostic port is hard to reach.
• Battery maintainer: A stable voltage above 12.4V is critical. Many programming failures happen because the battery drops below 12V during the process. Connect a charger if the battery is weak.

A common mistake beginners make is skipping the battery check. I’ve seen an X431 freeze mid‑programming because the voltage sagged. Always use a maintainer.

2. Connecting the X431 and Starting the Programming Session

1. Plug the X431’s OBD‑II cable into the vehicle’s diagnostic port, usually located under the dashboard on the driver’s side.
2. Turn the ignition to the ON position (engine off). Do not start the engine.
3. On the X431, tap Diagnosis → GAC → Trumpchi.
4. Select your exact model and year from the list. For example: Trumpchi GS4 2019 or Trumpchi GS8 2022. If the year is not listed, choose the closest year and verify later.

Pro tip: If the X431 does not have your specific Trumpchi model, update the software first. Go to the “Update” menu in the X431 app, download the latest GAC package, and then restart the scan.

3. Navigating to Key Programming / Immobilizer Function

After the vehicle identification is complete, you’ll see a main menu with various system options (Engine, ABS, Airbag, etc.). Look for Immobilizer or Key Programming. Tap it.

The submenu typically shows these options:

• Read PIN Code – Attempts to retrieve the PIN automatically from the ECU.
• Key Learn / Add Key – Starts the programming process for a new key.
• Erase All Keys – Deletes all programmed keys (useful when you’ve lost all keys).
• Read Key Info – Displays the number of keys currently learned.

4. Retrieving the PIN Code

You have three ways to get the PIN. Try them in order.

Option A: Auto Read via X431

Start with the easiest method. Select Read PIN Code. The X431 will send a command to the ECU, and after a few seconds, a 4‑digit number should appear on the screen. This works on many GAC Trumpchi models, especially those from 2016 onward. If the tool returns a value, write it down immediately.

What if auto‑read fails? The tool will display something like “Unable to read PIN” or “Function not supported.” Move to Option B.

Option B: VIN‑Based Calculation

Most LAUNCH X431 models include a built‑in VIN to PIN function. Go back to the main menu of the immobilizer section and look for “VIN to PIN,” “PIN Calculator,” or “Check PIN by VIN.” If you can’t find it, you may need to access it via the “Special Functions” menu.

1. Enter the 17‑character VIN of the Trumpchi (located on the dashboard near the windshield or on the driver’s door pillar).
2. The tool will apply an algorithm (typically the same one used by GAC) and display a 4‑digit number.

Common algorithm for older models: In some cases, the PIN is the last 4 digits of the VIN, but more often it’s a transformation – e.g., reversing the last 4 digits, or performing a simple addition. The X431 handles these variations automatically, so you don’t need to guess.

If the built‑in calculator fails, you can use an online GAC Trumpchi PIN calculator (requires internet). Enter the VIN on the X431’s web browser or your phone. The result will be your PIN.

Option C: Third‑Party PIN Lookup

Some X431 subscriptions (e.g., the “Security Code Database” add‑on) include a PIN lookup service. From the immobilizer menu, select “Online PIN Query” or “Security Database.” Enter the VIN, and if the code exists in the database, the X431 will display it. This method is reliable but requires an active internet connection and a valid subscription.

5. Entering the PIN Code During Key Programming

Once you have the PIN, you’re ready to program the new key.

1. From the immobilizer menu, select Add Key or Key Learn.
2. The tool will prompt you to enter the Security Code or PIN. Input the 4‑digit number carefully. Some models require leading zeros (e.g., 0045 instead of 45). The X431 will usually show a number pad; tap each digit.
3. Confirm the entry. The instrument cluster may flash, or the immobilizer warning light may turn solid. This indicates the ECU has accepted the PIN.
4. Follow the on‑screen instructions:
   • For “add key”: Place the new key into the ignition and turn it ON (or hold it near the steering column on push‑to‑start models). The X431 will then program the transponder.
   • For “program key”: You may need to perform additional steps like turning the ignition ON/OFF within a specific time window.
5. Wait for the tool to display “Key Programmed Successfully.”

6. Verifying the New Key

After the programming session, do not rush to disconnect the X431. Follow these checks:

• Turn the ignition OFF and remove the new key. Wait 10 seconds.
• Insert the new key and try to start the engine. It should crank and run.
• Test the remote functions: lock, unlock, trunk release, panic button.
• Test the original key as well to ensure it still works (unless you erased all keys).

If everything works, the programming is complete.

Troubleshooting Common PIN Code Issues

Here’s a handy reference table for the most common problems you’ll encounter, along with solutions:

Detailed Troubleshooting Steps for “PIN Code Incorrect” Error

The “PIN Code Incorrect” message is the most frustrating error because it halts the entire procedure. Here’s how to deal with it:

1. Re‑enter the PIN carefully. The X431 keypad can be unresponsive if you tap too fast. Enter each digit slowly, especially if zeros are involved. Some GAC Trumpchi models require the PIN to be entered with a leading zero (e.g., “0456” instead of “456”).
2. Verify the VIN. A typo in the VIN will produce an incorrect PIN. Watch for common mistakes: letter O versus number 0, letter I versus number 1. Check the VIN on the driver’s door sticker and on the dashboard – both should match.
3. Try a different PIN source. If you used the X431’s built‑in calculator, try an online calculation from a separate source (e.g., a mobile app). If you used an online service, try the X431’s auto‑read again after a power cycle.
4. Look for alternative PIN locations. On older GAC Trumpchi models (pre‑2018), the PIN may be stored in the BCM or behind the glove box as a 4‑digit code on a sticker. Pull the glove box and inspect the back wall. I’ve also seen the PIN printed on the inside of the keyless entry module cover.
5. Contact the dealer. As a last resort, a GAC dealership can provide the PIN using the VIN, provided you can prove ownership (registration and ID). This is the safest option if all else fails.

Advanced Tips for LAUNCH X431 Users

Once you’re comfortable with the basic procedure, these advanced tips will save you time and headaches:

• Using “Expert Mode” – Some X431 versions (e.g., PAD VII) have a hidden “Expert Mode” that allows you to input the PIN directly without navigating through the standard prompts. To enable it, go to Settings → User Level → Expert. This mode also unlocks additional functions like “Force Write Key” for emergency situations.

• Alternative Method for Lost All Keys – If you have no working keys for the Trumpchi, you must first erase all keys, then program new ones. Select Erase All Keys from the immobilizer menu. This often requires entering the PIN first. After erasing, you can program up to 3 or 4 new keys in one session. Be aware that the X431 may require a higher security access level for this – sometimes you need to log in with manufacturer credentials. In practice, I’ve found that many DIYers succeed by following the on‑screen prompts after erasing, while others need to call a dealer for a one‑time code.

• Remote vs. Immobilizer Programming – The PIN controls only the immobilizer (the transponder chip inside the key). The remote functions (locking/unlocking) are separate. On most GAC Trumpchi models, the remote is learned automatically when the transponder is programmed. However, on a few older models, you may need to do a separate “Remote Key Programming” sequence, often by turning the ignition ON/OFF a certain number of times. Check the X431’s menu – if there’s a “Remote Key” option, use it after immobilizer programming.

For more details on key programming for other Asian brands, check out our guide on [link to related guide on similar topic].

Frequently Asked Questions (FAQ)

Where can I find the PIN code for my GAC Trumpchi?

The PIN is not physically written anywhere on the vehicle. You must retrieve it via a diagnostic tool like the LAUNCH X431 that reads it from the ECU, or calculate it from the VIN using a specialized service (either the X431’s built‑in calculator or an online database). Dealers can also provide it with proof of ownership.

Can I program a key without the PIN code?

No, the PIN code is mandatory to authorize key programming on all GAC Trumpchi vehicles. Without it, the immobilizer system will reject the new key and the engine will not start.

What if my LAUNCH X431 doesn’t support GAC Trumpchi?

First, update the X431 software via the “Update” menu – GAC Trumpchi support is typically included in the Asian vehicle package. If it still doesn’t appear, you may need a separate GAC‑specific module (some older X431 models require an add‑on). Alternatively, use a different scan tool like Autel or Xtool that supports Trumpchi.

How many keys can I program at once?

Most GAC Trumpchi models allow up to 3 or 4 keys. The X431 will show you the current number of programmed keys during the session. You can add keys one by one, or erase all and program multiple new keys together.

Will entering the wrong PIN lock the system?

Yes. After 3 to 5 failed PIN attempts (depending on the model), the immobilizer will lock out for 15 to 30 minutes. The engine will not start during this period. If you exceed the attempts, wait with the ignition OFF for at least 30 minutes before trying again. Do not repeatedly attempt – it may trigger a permanent lock requiring dealer intervention.

About the Author

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

Related Posts

• How to Add a Remote Key to a GAC Trumpchi Using LAUNCH X431 (No Dealer)
• GAC Trumpchi All-Keys-Lost Key Matching with LAUNCH X431 & 8-Digit PIN
• How to Replace Anti-Theft Module on GAC Trumpchi Using LAUNCH X431
• How to Program a Smart Key on a GAC Trumpchi M8 (2019–2024) Using LAUNCH X431
• How to Add a Key to a GAC Trumpchi GA8 (2015–2023) with LAUNCH X431