Learn to program your BAIC BJ20 key using a LAUNCH X431 scanner. Step-by-step guide for add key & all keys lost modes, troubleshooting, and tips. Save on dealer costs.

How to Program BAIC BJ20 Keys with LAUNCH X431

Published: June 22, 2026

Quick Answer: Programming Your BAIC BJ20 Key

If you own a LAUNCH X431 scanner (such as the X431 PAD VII, X431 PRO, or X431 V+), you can program a new key for your BAIC BJ20 yourself. You'll need at least one working key, a compatible blank key, and the scanner connected to the vehicle's OBD-II port. The process involves reading the vehicle's immobilizer system, selecting the key programming function, and following on-screen instructions. When all keys are lost, an extra 10-minute waiting step is required. This guide walks you through the entire procedure step by step.

Why Program Your BAIC BJ20 Key Yourself?

Losing a car key or needing a spare can be frustrating—and expensive if you visit a dealership. A LAUNCH X431 diagnostic tool puts that power in your hands. Not only does it handle key programming for the BAIC BJ20, but it also covers hundreds of other vehicle models. By doing the job yourself, you save between $50 and $200 compared to dealer or locksmith costs, and you gain the confidence of knowing your equipment works when you need it.

But before we dive into the steps, let's make sure you have everything ready.

Tools Required and Vehicle Preparation

To program a BAIC BJ20 key, gather these items:

Tool / Item	Purpose
LAUNCH X431 scanner	Any model with BAIC software installed and updated
Working key	Needed for "Add Key" mode; not required for "All Keys Lost"
Blank key	Must be cut to match your BJ20 ignition; use genuine BAIC or quality aftermarket
Stable internet	For software updates and real-time support
Battery charger	Keep vehicle battery above 12.5V during programming

How to prepare the vehicle:

Park the car on a level surface and engage the parking brake.
Turn the ignition OFF and remove any keys from the ignition slot.
Close all doors (this prevents electrical noise from door switches).
Connect your battery charger to the vehicle's battery terminals—never rely on battery power alone for programming.

Check your X431: Before starting, verify that the BAIC software pack is installed. On the scanner's home screen, go to "Software Update" → "BAIC" and install the latest version. Older firmware may lack specific BJ20 protocols, leading to communication errors.

Step-by-Step Programming Process

Follow these steps in order. If you encounter any issues, refer to the troubleshooting section later in this article.

1. Launch the BAIC Diagnostic Software

Insert the working key into the ignition and turn it to the ON position (do not start the engine). The dashboard lights should illuminate.
Connect the X431 scanner to the OBD-II port (located under the dashboard on the driver's side).
On the scanner, tap "Diagnosis" → "BAIC" → "BJ20" (or "BJ20 Plus" if your vehicle is the newer variant).
The system will auto-detect the vehicle's VIN. Verify it matches your car's VIN plate (visible through the windshield on the driver's side), then tap "Confirm".

2. Navigate to Key Programming

From the main diagnostic menu, select "Immobilizer" or "Anti-Theft System" (the exact name varies by software version).
Choose "Key Programming" → "Add Key" (if you have a working key) or "All Keys Lost" (if you have no working keys). See the reference table below for guidance.

3. Enter Security Code (If Required)

Some X431 versions prompt for a 4-digit security code. This code is not always needed, but when it appears, try the following in order:

0000 (most common default)
1234
The last four digits of your vehicle's VIN (remove letters, use only numbers)
Contact a BAIC dealer with your chassis number for an official code

Important: If you enter the wrong code three times, the immobilizer may lock you out for 10 minutes. Wait patiently before retrying.

4. Program the New Key

Insert the new blank key into the ignition and turn it to the ON position. If your BJ20 has push-to-start, hold the key fob near the start button.
On the X431, tap "Start Programming." The scanner will communicate with the immobilizer module.
A countdown timer may appear (commonly 30 seconds). Do not turn the ignition off during this time.
When the screen displays "Programming Successful," remove the new key.

5. Test All Keys

Turn the ignition OFF for 10 seconds.
Insert the original working key, turn to ON, and verify the engine starts. The immobilizer light on the dashboard should turn off after about 2 seconds.
Repeat the test with the newly programmed key. Both should start the engine without issue.

When to Use "Add Key" vs. "All Keys Lost"

Choosing the wrong function can waste time or cause errors. Here's a quick decision guide:

Your Situation	Recommended Function	Why
You have at least one working key	Add Key	Fastest method; adds new key without erasing existing ones
All keys lost or none work	All Keys Lost	Erases all old key data, then lets you program new keys from scratch
Replacing the immobilizer module	All Keys Lost	The module has no stored keys, so a full reset is mandatory

Troubleshooting Common Issues

No programming session goes perfectly every time. Here are the most frequent problems and how to solve them.

"All Keys Lost" Scenario

If you've lost all keys or the immobilizer doesn't respond:

On the scanner, select "All Keys Lost" → confirm.
Turn the ignition OFF and wait for 10 minutes. The vehicle must remain powered (do not disconnect the battery). Use a battery charger to prevent voltage drop.
After the wait, turn the ignition ON with a new blank key.
Select "Program New Only" and follow the steps.

Still failing? The immobilizer module may be faulty. Consider contacting a professional locksmith or BAIC dealer for module replacement.

Communication Failure with Scanner

Check the OBD-II cable connection. Wiggle the connector gently—sometimes a loose fit causes intermittent errors.
Restart both the X431 and the vehicle. Turn ignition OFF, wait 2 minutes, then retry.
Update the X431 firmware via WiFi. Older versions sometimes lack specific protocols for the BJ20's immobilizer.

Key Works in Ignition but Engine Won't Start

The transponder chip inside the key is not being read. Use the X431's "Read Key Status" function to verify recognition.
Replace the blank key with a genuine BAIC chip key. Aftermarket keys sometimes fail because of chip incompatibility—especially for the 4D (Pcf7936) transponder used by the BJ20.

Security Code Not Accepted

If "0000" and VIN digits fail, the immobilizer may have a custom code set by a previous owner.
Contact a BAIC dealer with your chassis number. They can calculate the correct code (this service may cost a small fee).

Frequently Asked Questions

Q: Can I program a BAIC BJ20 key without a LAUNCH X431?
You need a professional diagnostic scan tool that supports BAIC immobilizer functions. Other options include Autel, Xtool, or dealership tools. The LAUNCH X431 is popular because it is widely available, user-friendly, and regularly updated. For a guide on choosing the right X431 model for your workshop, check out our article on X431 scanner models for BAIC vehicles.

Q: How much does it cost to program a BAIC BJ20 key?
If you own an X431 and cut the key yourself, the only cost is the blank key (typically $15–$40). At a dealership, expect $50–$150. A locksmith may charge $80–$200. Doing it yourself saves significant money.

Q: My X431 doesn't show "BAIC BJ20" – what do I do?
Update your scanner's software. Go to "Software Update" → "BAIC" → install the latest pack. If the BJ20 model is still missing, contact LAUNCH support; some regional versions require a separate download.

Q: Do I need a specific blank key?
Yes. The BAIC BJ20 uses a 4D (Pcf7936) transponder chip. Buy pre-cut keys from a BAIC dealer or a reputable locksmith. Avoid cheap universal blanks—they often fail to communicate with the immobilizer.

Q: Can I program a key using an app on my phone?
No. Smartphone apps alone cannot access a vehicle's immobilizer system. The LAUNCH X431 is a standalone scanner that communicates directly with the car's ECU through the OBD-II port.

Q: How long does the whole process take?
If you have one working key, about 30 minutes. For an "All Keys Lost" scenario, allow up to 1.5 hours because of the 10-minute waiting period.

Q: Will programming affect my existing remotes (keyless entry)?
No. Key programming only affects the transponder used for engine start. Remote keyless entry functions are managed separately. If your remotes stop working after programming, use the X431's "Remote Key" menu to re-synchronize them.

Q: What if my BAIC BJ20 has push-to-start?
The process is nearly identical. Keep the key fob near the ignition button throughout programming. The X431 guides you through a "proximity key" mode.

Q: Can I program a key if my battery is low?
Never attempt key programming with a weak battery. Low voltage can corrupt the programming sequence or damage the immobilizer module. Always connect a battery charger rated at 10 amps or higher before starting.

Final Tips for Success

Work in a quiet environment – Electrical noise from nearby devices (like phone chargers or welding equipment) can interfere with the X431's communication.
Read the on-screen prompts carefully – The LAUNCH X431 software is designed to guide you step by step. Ignoring a prompt is the most common cause of failure.
Keep your X431 updated – Manufacturers release new software patches that improve compatibility with newer vehicle models. Set a reminder to check for updates every few months.
Have a backup plan – If you cannot program the key after three attempts, the immobilizer may have a hardware issue. Our troubleshooting guide for BAIC BJ20 immobilizer problems can help you diagnose further.

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/

How to Program BAIC BJ20 Keys with LAUNCH X431 | Step-by-Step Guide