With Keydiy KD-X4 + KEYDIY ZB31 Universal Smart Remote + KEYDIY PAK09 Phone as Key, you can successfully add up to 3 Mercedes-Benz FBS4 keys without waiting weeks for dealer delivery. No more 2–4 week delays — the entire job can be completed on the same day.
This method allows you to add Mercedes FBS4 full keyless keys quickly and safely using original key data and KEYDIY tools.
Tools Required
- Original Mercedes-Benz key
- KEYDIY PAK09 Phone as Key (BBA Box)
- KEYDIY ZB Series Smart Remote (e.g. ZB31)
- KEYDIY KD-X4 App
Step-by-Step Instructions
Step 1: Remove Original Key PCB
Disassemble the original Mercedes key and carefully remove the PCB.
Step 2: Wiring the Original PCB to PAK09
Open the KD App and navigate to:
Learning Center → Help Center → Wiring Diagrams → Original Remotes
Find the wiring diagram that matches your original Mercedes remote.
Follow the diagram and solder the PCB correctly.
Next:
- Remove the back cover of the PAK09 Phone as Key box
- Insert the adapter cable into the corresponding trigger connector
- Place the soldered original PCB inside the PAK09
- Close the back cover
Power on the Keydiy PAK09:
- Short press the power button once
- Then long press for 3 seconds
When the indicator light flashes, the device is powered on successfully.
Step 3: Generate a New Physical Key with KD-X4
PAK09 supports generating physical keys using KD B / ZB series remotes.
In this example, a KD ZB smart remote is used.
Place the KD ZB remote into the KD-X4
Open the KD App
Go to Remote Function → Vehicle Remote
Select the correct remote program
Generate the KD ZB smart remote
Generation completed successfully.
Step 4: Pair PAK09 with Phone as Key App
Open the Phone as Key App:
- Tap the Settings icon
- Enter Device Management
- Scan for nearby devices
- Select the PAK kit to connect
The default password is 000000.
For first-time pairing, you will be prompted to change the password.
Step 5: Add the New FBS4 Key
- Go to Settings
- Scroll down to Key Management
- Tap Enter Matching Mode
Before the countdown finishes, press any button on the generated remote to add the key.
You can add up to 6 physical keys using this method.
Once completed, the Mercedes-Benz FBS4 spare key is added successfully.
Important Notes
KD FBS4 remotes cannot be generated directly
They must be paired through the PAK09 Phone as Key first
Original key data is required for this process
This solution provides a fast, reliable, and professional way to add Mercedes-Benz FBS4 full keyless keys without dealer delays — perfect for locksmiths and workshops looking to save time and improve efficiency
