Toyota 8A-BA & 4A-BA All Keys Lost: Autel Key Programming Guide

As vehicle security has improved, the process, time, and cost involved in programming a new key—especially when a key is lost or all keys are lost—have gradually increased. The Toyota 8A-BA and 4A-BA are the next-generation, high-security anti-theft key chips that Toyota has adopted in recent years. If you have one of these two key models and are facing programming issues, please refer to our user guide.

To address the issue mentioned at the beginning, Autel key programming tools have continued to innovate and provide solutions. This guide will use tools such as the Autel key programmer and smart key simulator to walk you through the process of programming a new Toyota 8A-BA & 4A-BA key.

What You Need Before Starting

Before you begin the key programming process for a vehicle where all keys have been lost, you must first verify several details: confirm that the key model is compatible, ensure that your Autel key programming tool supports the specific vehicle for this operation, and identify any additional tools that need to be prepared in advance. A detailed explanation follows.

Verify the Vehicle Key Chip

After switching to the latest 30-pin smart anti-theft module (such as the TMLF19D architecture), the vast majority of TNGA-platform models that were redesigned or launched in 2021 or later have fully transitioned to the 8A-BA or 4A-BA smart key chip protocols.

Source: Information obtained through AI-assisted search. Please refer to your vehicle’s owner’s manual for specific applicability.

Other Methods for Identifying Key Chip Types

1. Check the VIN and model year (fastest method)
2. Inspect the anti-theft module connector
3. Automatic scan using a key programming tool

What Tools Are Needed for Programming Car Keys?

This guide primarily uses the Autel key programmer. You will need the following tools:

• One key programming tool: Autel IM608 Pro 2
• One smart key simulator: Autel APB112
• Four jumper wires
• A new blank key

The tools required may vary depending on the vehicle model; the provided list of tools is for reference only. Additionally, before purchasing an Autel key programming tool, you should verify its vehicle coverage. You may consult with official customer service or check the information yourself using the Autel key programmer "Vehicle Coverage Lookup Guide."

Other Matters to Be Determined

In addition to the information that needs to be determined in advance and the key programming tools that need to be prepared, as mentioned above, there are also some aspects of the programming environment that need to be confirmed and prepared:

• Ensure a stable network connection
• Keep the vehicle parked securely and steadily
• Make sure the ignition switch is functioning properly
• Locate the vehicle’s OBD-II diagnostic port
• Locate the vehicle’s intelligent main control module

Note: The location of the smart control module may vary by vehicle model.

For a separate walkthrough covering supported APB112 applications, see our guide to Toyota all keys lost with Autel APB112.

How to Program a New Toyota 8A-BA or 4A-BA Key

This guide to programming car keys uses the Autel IM608 Pro 2 to program a new key for a Toyota Frontlander HV as an example. Some steps may vary slightly for other models or other Autel key programming tools, but the overall process should be largely the same.

Step 1: Selecting the Correct Vehicle Information

Specific Path: MaxiIM > IMMO > Toyota > Manual Selection > Other > FRONTLANDER HV > Smart Key > 4A > Control unit > Keyless System(CAN)

If you choose to enter the vehicle model manually, you will need to have information such as your vehicle's model and key type ready beforehand. Ensuring that the vehicle information is correct is crucial for the Autel key programming tool to communicate properly with the vehicle.

Choose the right vehicle infomation

Step 2: Back up IMMO Data

Perform the "Back up IMMO data" function to obtain the vehicle's EEPROM bin file, which is used to generate an analog key and facilitate the PIN-free process

Ensure that the network connection of the device is good. Turn the ignition off, and turn the hazard warning lamps on and off once.

Follow the on-screen instructions on the Autel IM608 Pro 2 to perform the following steps:

Connect the vehicle’s OBD-II diagnostic port, the Smart Control Module A, and the main test cable using jumper wires as shown in the diagram (Note: The location of Smart Control Module A may vary depending on the vehicle model):

1. Use jumper wires to connect the main test cable to the vehicle’s OBD-II diagnostic port, and connect the power supply (+12 V) and ground (GND).
2. Use jumper wires to connect the main test cable to the Smart Control Module A connector, and use jumper wires to connect CAN-H and CAN-L to pins 1 (CAN-H) and 2 (CAN-L), respectively, on the Smart Control Module A connector.

After connecting the wires, read the IMMO data and save it in the Autel key programming tool.

Note: You must turn off the bluetooth function of the device and connect VCI to diagnostic tool with USB cable otherwise the function may fail!

Back IMMO data operation guide

Step 3: Generate Analog Key

Perform the "Generate analog Key" function by loading the backed-up EEPROM bin file, generate the analog key and verify that its emergency ignition function works correctly.

Connect the Autel APB112 Smart Key Simulator to retrieve key information until the screen displays the message “Generate analog key complete.”

Note: analog key must be powered on, never cut off! Please close the analog key to the push start (Start/Stop) button and press the start (Start/Stop) button. If the instrument lights up successfully, click "Yes" to continue. If the instrument fails to light up, click "No" to continue generating the next analog key.

Generate An Analog Key

Step 4: Add a Smart Key

Perform the "Add smart key" function by loading the backed-up EEPROM bin file to enable PIN-free operation

1. PIN Verification

This function serves to learn keys. Please complete the steps within specified time:

• Turn on the ignition: Start the vehicle using the generated simulated key
• Enter the Vehicle VIN
• Select EEPROM data

2. Key Learning

• Keep a learned key(analog key) close to the start button
• Keep a key(new blank key) you want to learn close to the start button
• Learning succeeded

Add a smart key

Step 5: Verify that the Newly Programmed Key

Test whether the button functions on the newly programmed key work correctly—for example, check if it can properly unlock the vehicle, operate the windows, open the trunk, etc. The specific functions to test will depend on the particular key model. The primary goal is to verify that the key is fully functional.

Reference Videos for Operations

What to Check If Key Programming Fails

Start with the error message on your Autel device, then check the following:

• Vehicle and key compatibility: Confirm the selected vehicle, immobilizer system and replacement key specifications.
• Power and connections: Check that the vehicle’s power supply is stable and all required cables and adapters are securely connected.
• Procedure and prompts: Make sure you selected All Keys Lost and followed the instructions for ignition status and key placement.
• Software and network: Confirm vehicle coverage and check your internet connection if the device requests online access.

If programming reports success, test starting, remote locking and smart entry where fitted. If the issue persists, save the error message and contact Autel support with the vehicle and device details.

Final Thoughts

With the right Autel key programmer and a compatible replacement key, you can complete the all-keys-lost procedure for supported Toyota 8A-BA and 4A-BA systems. Confirm vehicle coverage before starting, follow the device’s prompts, and finish by testing every programmed key for starting, remote locking, and smart entry where equipped.