Step-by-step guide to replace and recode a BYD Han EV keyless start module using the LAUNCH X431 IMMO Elite. Includes diagnosis, tools, initialization, and key programming.

How to Replace and Recode a BYD Han EV Keyless Start Module via LAUNCH X431 IMMO Elite

Published: May 26, 2026

Quick Answer: Key Steps Overview

Replacing and recoding a BYD Han EV keyless start module requires a professional-grade diagnostic tool like the LAUNCH X431 IMMO Elite. Start by disconnecting the 12V battery and waiting five minutes. Then remove the center console trim, unbolt the old module, install the new one, and reconnect everything. Using the IMMO Elite, perform an immobilizer initialization to sync the new module with the vehicle’s BCM and ECU, followed by key programming for all available key fobs. The entire process typically takes 30–60 minutes. You’ll need the vehicle’s original keys and a stable internet connection for the diagnostic software to download any required data.

Why the Keyless Start Module Fails on a BYD Han EV

The keyless start module—sometimes called the push-button start module or start-stop module—is a critical component in modern EVs like the BYD Han. When it starts to fail, you’ll notice one or more of these symptoms:

Intermittent start failure: You press the start button with the brake pedal, but nothing happens.
"Key not detected" error on the dashboard, even when the key fob is inside the car.
Complete loss of push-button start function, forcing you to use the mechanical key blade to unlock the door, but still being unable to start the vehicle.

Root Causes

BYD Han owners have reported several common failure causes:

Water damage: The keyless start module sits beneath the center console, right where windshield leaks or spilled drinks can soak it. Windshield seal failures in earlier Han models are a known weak point.
Electrical surges: A voltage spike from a faulty 12V battery or a jump-start gone wrong can fry the module’s internal circuitry.
Internal component failure: Like any electronic module, capacitors and solder joints degrade over time, especially in hot climates.

How to Diagnose with the LAUNCH X431 IMMO Elite

Before ordering a replacement module, confirm the diagnosis. Connect the LAUNCH X431 IMMO Elite to the OBD-II port, select BYD → Han EV → 2022+ (or your model year), and navigate to the Body Control Module (BCM) or Immobilizer system. Read fault codes. Look for codes like U0168 (Lost Communication with Keyless Entry Module) or B1A53 (Keyless Start Module Internal Fault). If you see these, you’ve likely found the culprit.

Prerequisites Before You Begin

Don’t skip this section. Preparation prevents halfway headaches and electrical damage.

Required Tools

Tool	Purpose
LAUNCH X431 IMMO Elite (latest firmware)	Immobilizer initialization and key programming
Plastic trim removal pry tools	Safely remove center console panels
Torx screwdrivers (T20 and T25)	Remove module bracket screws
Multimeter	Check for 12V power and ground at the module connector
Small flathead screwdriver	Release electrical connector locking tabs

Required Parts

OEM BYD Han EV keyless start module – typically part number 28200201 or equivalent. Avoid generic aftermarket modules unless verified to work with Chinese-market BCMs. For North American or European Han models, cross-reference your VIN with the dealer parts department.

Safety Precautions

Disconnect the 12V battery negative terminal – always do this before handling any electronics under the center console.
Wait at least 5 minutes – this gives the airbag backup capacitor time to discharge. Rushing this step risks a short circuit that can trigger the SRS airbag system.

Step-by-Step Replacement and Recoding Process

I’ll walk you through this procedure exactly as I would if I were beside you in the workshop. Take your time with each step.

1. Locating and Removing the Old Module

The keyless start module is typically located beneath the center console, near the gear selector or cup holder area. Here’s how to access it:

Remove the center console trim panels: Start with the side panels (driver and passenger side). Use plastic pry tools to gently pop the clips. Work from back to front.
Lift the cup holder assembly: In most BYD Han EVs, the cup holder trim lifts out after removing two screws hidden under rubber mats. Set it aside.
Locate the module: You’ll see a small black box (roughly 3x4 inches) with a multi-pin connector and two or three Torx screws holding it to a metal bracket.
Disable the electrical connectors: Press the release tab on the connector and gently wiggle it out. Don’t pull on the wires.
Unscrew the module bracket: Use a T20 Torx driver to remove the screws. Lift the module straight out.

Pro tip: Take a photo of the connector orientation before unplugging it. This makes reinstallation foolproof.

2. Installing the New Module

Align the new module in the bracket. Make sure the connector port faces the same direction as the old unit.
Secure the bracket screws – tighten to 2–3 Nm (finger-tight plus a quarter turn). Over-tightening can crack the plastic housing.
Reconnect the electrical connector – push until you hear a distinct click. Tug gently to confirm it’s locked.
Do not reassemble the trim yet. It’s much easier to verify functionality before the console goes back together.

3. Connecting the LAUNCH X431 IMMO Elite

Plug the LAUNCH X431 into the OBD-II port – it’s located under the driver’s side dashboard, usually near the hood release.
Turn the ignition to ACC – press the start button once without pressing the brake pedal. The dashboard lights should illuminate, but the drivetrain stays off. This powers the new module so the tool can communicate.
Launch the IMMO Elite app on the X431 tablet. Select BYD → Han EV → 2022+ (or the appropriate model year for your vehicle). If your tool doesn’t have the Han EV profile, update the software via Wi-Fi before proceeding.
Wait for the vehicle identification – the tool will automatically read the VIN. Confirm it matches your car.

4. Performing Immobilizer Initialization

This is the core of the recoding process. The new module is a blank slate—it doesn’t yet know which car it belongs to.

Navigate to Immobilizer → Replace Keyless Start Module.
The tool displays a prompt: “Have you installed the new module? Confirm (Yes/No).”
Select Yes.
Follow the on-screen instructions – the tool will communicate with the BCM and ECU to write the vehicle’s immobilizer data (including VIN and security codes) into the new module.
Do not interrupt the process – it can take 2–5 minutes. The screen may freeze for a few seconds. That’s normal. Keep the ignition in ACC mode. If you turn it off, the initialization will fail and you’ll have to start over.
Wait for the confirmation message: “Initialization completed successfully.”

5. Programming All Keys

The new module is now synced to the car, but it has no key fobs paired. You must program all keys, even the ones you think already work.

Select Key Programming → Program Keys from the IMMO Elite menu.
The tool will ask you to insert the first key into the key slot (if your BYD Han has a physical key slot) or hold it near the start button. Most Han models use proximity programming:
- Hold key fob #1 within 3–6 inches of the start button.
- Press the START button once (without brake). The tool will say “Key detected.”
- Remove the key and repeat with key fob #2.
- Continue for up to four keys.
After each key – the tool confirms successful pairing with a beep and on-screen message.
Important: Even if you only have two keys, the tool may ask you to cycle through all four positions. Press START with no key at the empty positions—the tool will skip them.

6. Verifying Functionality

Disconnect the LAUNCH X431 – unplug it from the OBD port.
Turn the ignition off, then back to ACC. The dashboard should show no immobilizer warning lights.
Test each key individually:
- Press lock/unlock buttons – confirm remote range (30+ feet).
- Walk up to the car with the key in your pocket – passive entry should unlock the door.
- Press START with brake pedal – the car should go into READY mode (EV drivetrain active).
Check for warning lights – if you see an airbag or ESC light, there may be a loose connector under the console. Recheck your wiring.

Troubleshooting Common Issues During Recoding

Even experienced technicians hit snags. Here’s how to handle the most common ones.

Problem	Likely Cause	Fix
“Communication failed” error	Loose OBD connector, ignition off, or low tablet battery	Recheck OBD plug, ensure ignition is ACC, restart the IMMO Elite app
Key not detected during programming	Dead key fob battery or wrong placement	Replace fob battery (CR2032). For some BYD models, place the fob on the pad near the cup holder.
New module won’t sync	Wrong part number or aftermarket module	Verify module P/N matches your VIN. Some aftermarket units require dealer-level flashing with a J2534 passthru.
Tool stuck at “Initializing”	Outdated firmware	Connect to Wi-Fi, update IMMO Elite to the latest version, then restart the procedure.
Dashboard shows “EPS Fault” or “ABS Fault” after recoding	Module initialization triggered a temporary warning	Drive the car a few feet – many EV modules clear these after a short drive. If persistent, run a full system scan with the X431.

What if the recode fails mid-process? Keep the diagnostic tool connected and ignition ON. Restart the IMMO Elite application and repeat the initialization step from the beginning. Do not attempt to start the engine until the process completes successfully.

When Professional Help Is Needed

You can handle most of this job yourself if you’re comfortable with trim removal and basic diagnostics. But in these situations, call in a professional:

You cannot establish communication after three attempts – the new module may be defective, or your IMMO Elite firmware may not support your specific Han model year. Contact BYD technical support or a specialized locksmith.
Your BYD Han is a 2023+ model with a Central Gateway (CGW) – some newer Chinese-market EVs lock out aftermarket tools. You may need a gateway bypass cable, which only licensed technicians should install.
You have lost all keys – the IMMO Elite can still sync the new module, but without at least one existing key to copy, you’ll need a dealer to generate a security PIN code from the vehicle’s VIN. Locksmiths with access to BYD’s secure database can also help.

Frequently Asked Questions

Q: Can I use any LAUNCH X431 model for this job?

Only the LAUNCH X431 IMMO Elite or higher-end models like the X431 PROS IMMO Plus support BYD Han EV keyless module replacement. Basic X431 diagnostic tools lack the immobilizer functions required for this procedure. Check your tool’s compatibility before starting.

Q: Do I need a security code (PIN) for the BYD Han EV?

For model years 2021–2023, the LAUNCH IMMO Elite retrieves the PIN automatically via the OBD port. For older models (2020 and earlier), you may need to enter a 4-digit code obtained from the dealer using the VIN. The tool will prompt you if a manual PIN is required.

Q: Will I lose emergency key functions?

No. Recoding the keyless module preserves the mechanical key blade’s door lock/unlock function. The transponder chip inside the key fob remains paired. You can still unlock the door manually if the key fob battery dies.

Q: How long does the battery need to be disconnected before removal?

At least 5 minutes. This allows the airbag backup capacitor to discharge completely. For extra safety, wait 10 minutes if you’re working near the steering column or SRS components.

Q: Can I reuse the old keyless start module in another car?

No. The module is married to the vehicle’s BCM during initialization. Once paired, it cannot be swapped to another car without a full immo data flash, which requires a dealer-level tool and security access.

Q: What if the recode fails mid-process?

Keep the diagnostic tool connected and the ignition ON. Restart the IMMO Elite application and repeat the initialization step. Do not attempt to start the engine until the process completes successfully. If it fails again, check for loose connectors or update the firmware.

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/

For more information on using the LAUNCH X431 IMMO Elite for other vehicles, check out our guide on [link to related guide on immobilizer programming for Chinese EVs]. If you’re new to IMMO Elite tools, our article [link to getting started with LAUNCH X431 IMMO Elite] covers the basics of setup and navigation.

Replace & Recode BYD Han EV Keyless Start Module | LAUNCH X431 IMMO Elite Guide