This guide explains how to add a smart key to a 2026 Lexus RX350H using Lonsdor K518 PRO, LT21-07 Smart Key, and FP30 cable.
The LT21-07 supports the latest 2025+ Lexus 8A-B6 system, including the RX, TX, NX, UX 350, and RT h+ series. Follow the steps below to generate the smart key, back up the immobilizer data, and complete key addition.
1. Generate the LT21-07 Smart Key
Navigate to Generate Smart Key >> Lexus >> RX350H >> 2025- RX350H B6 433.58/434.42.
Insert LT21-07 into K518 PRO key slot and select Generate.
Once generation is successful, select Cancel to return to the previous menu.
2. Back Up the IMMO Data
Go to Immo & Remote >> Lexus >> Select from Vehicle >> RX350H >> 2024-2026 >> Smart Key (8A_B6) >> Backup Immo Data.
Connect the Toyota FP30 cable to the PEPS case. Ensure the device has an active network connection, turn on the ignition, and follow the on-screen instructions.
Enter a name for the backup file and select OK. Wait until the IMMO data backup is completed successfully.
3. Add the Smart Key
Select Add Smart Key. Keep the network connection active, ensure the vehicle battery is fully charged, and turn on the ignition.
Select Load the read D-FLASH data of PEPS to acquire 12-bit PIN code. Then load the previously saved RX350H.bin file.
Check the current key count. Place the original key in the ignition first, followed by the LT21-07 smart key.
Once the key addition process is complete, select OK, turn off the ignition, and proceed to test the keys.
4. Verify the Keys
After programming, test both the original key and the newly added Lonsdor LT21-07 smart key.
Both keys successfully started the 2026 Lexus RX350H, and the remote functions worked normally.
