If you’ve purchased a 2012 Subaru Legacy and need to program a transponder key for it, you can easily do so using the VXDIAG SSM3 tool. Below is a detailed guide on how I programmed the transponder keys for my 2012 Subaru Legacy using the VXDIAG OBD2 Diagnostic Tool.
Preparation
First, I bought two transponder keys from eBay, planning to program them myself. I purchased the VXDIAG VCX SE pro 3 in 1 interface. This tool from vxdiag official store, www.vxdiag.com, comes with several software options for different car brands, and I chose Subaru, Ford, and GM. After that, I began the key programming process following the steps below.
Step 1: Insert the Key and Confirm It’s Not Programmed
First, I inserted the unprogrammed key into the ignition. At this point, the dashboard showed a vehicle icon with a key, indicating that the key was unprogrammed, and the vehicle wouldn’t start. Then, I inserted a programmed key, and no warning light appeared, and the car started normally.
Step 2: Obtain the Necessary Codes
Before starting the programming process, I needed some key codes. Subaru provides a technical service bulletin that explains how the immobilizer and key programming works. To obtain the immobilizer code, I had to visit a Subaru dealership, provide proof of ownership of the vehicle, and obtain the code from them.
Step 3: Connect the VXDIAG SSM3 Tool
I connected the VXDIAG VCX SE interface to the vehicle and launched the SSM3 software. Once the software opened, I selected "Subaru" and then chose "Monitor 3" as the device. After that, I selected "All mother modules" and entered the "Immobilizer" module. The system then asked if the vehicle supports keyless start. Since my Legacy doesn’t have this feature, I selected "No."
Turn on the ignition switch with the working key.
and select yes.
Step 4: Enter the Teaching Operation Code
In the next step, the SSM3 tool prompted me to enter the teaching operation code. This code can be found online. For the 2012 Legacy, I used the code “3781,” and successfully passed this step.
Step 5: Register the Key
Next, I began the key registration process. This step might take a little while. The SSM3 tool asked for the security ID, which I also had to get from the Subaru dealership. Then, I inserted my first key and selected “Register Key.”
Step 6: Register the Second and Third Keys
Since I had three keys to program, the system prompted me to insert the new keys and register them. I selected “Yes,” and followed the prompts to complete the registration of the second and third keys. It’s important to note that when registering a new key, the system will delete all previous keys. Therefore, if you have multiple keys to register, you should do them all at once.
Step 7: Program the Remote
Since my parents’ old car had a remote starter installed, but they lost the remote’s switch, I decided to try programming the remote starter. Using the VXDIAG SSM3 tool, I was able to easily proceed with this task, although I haven’t fully tested whether it works yet.
Step 8: Complete the Programming
After successfully registering all the keys and remotes, I clicked "Quit" to finish the process. Now, all my keys work, and the vehicle starts smoothly.
Conclusion
By using the VXDIAG Car diagnostic tool, I successfully programmed the transponder keys, remote, and registered all the keys for my 2012 Subaru Legacy. This tool’s powerful features not only saved me time from going to the dealership but also allowed me to avoid high programming fees. Considering that I can use it multiple times, it has almost "paid for itself." For car owners who want to program their own keys, the VXDIAG tool is definitely a worthwhile investment.
