Remember that the fob has multiple transmission modes that all have to be paired.
1) The nearfield transmitter that unlocks the doors when you reach for the handle and press the push-to-start button.
2) The lock / unlock buttons that talk to the RKE via 315 (old) or 433 (new) MHz transmitters.
3) The passive encryption chip (the "wedge") that responds to the immobilizer as your backup should the battery powered nearfield system fail.
You are setting up all 3 systems at once during the programming.
A few other things concern me, and an extensive search brings up conflicting answers....
A) Do you need to bring all keys? On my last two local locksmith key adding adventures (2014 Outback and 2018 Forester - both with conventional keys - so only passive G chip for the immobilizer and buttons for the RKE) I was instructed to bring all keys. Everything was deleted, and once in programming mode all keys were inserted and the engine started. At the end (original 2 keys with buttons and one valet, plus the new button key for our daughter), 4 keys were newly programmed to the vehicle, and then the vehicle was taken out of program mode. But it was done with an Autel IM608 tool, and not SSM4. So
@j3rf is likely correct. With the right programming knowledge, deleting all keys might not be necessary. Just one original gets wiped and reset, and one new key gets programmed.
B) Ebay and other sellers often claim that their used fobs have been "wiped" / reset, allowing them to be paired with your vehicle. True or false? Apparently not all vehicle systems are identical. Used Toyota smart fobs can be reset using a Tango box that captures data from your master key and overwrites that onto your used Ebay key to remove it's old vehicle association. So apparently the key/vehicle pairing can be bidirectional. I'm still reading to see if/how this works with Subaru smart fobs.
Looking for verification and a Subaru-specific test case, but.......
Googling: Can a Tango box reset a used Subaru smart key fob?
Gave this:
Yes, a
Tango key programmer, with the appropriate specialized software activation, can reset a used Subaru smart key fob so it can be reprogrammed to another vehicle.
Subaru dealerships typically cannot or will not reset a used smart key fob, as their diagnostic tools are designed to program new fobs to a specific vehicle's system, not to "virginize" used ones. However, professional locksmiths or technicians using advanced aftermarket tools like the Tango programmer can perform this reset.
The specific software activation required is often labeled as "Tango Software Reset of Toyota/Lexus/Subaru Smart Keys" (covering 40, 80, and 128-bit keys). This function allows for the unlocking/resetting of the key's transponder chip wirelessly, effectively wiping its previous vehicle data and allowing it to be treated as a new, "virgin" key for the programming procedure in another compatible Subaru.
And this is a statement from the North Coast Keyless site for a Subi Forester used smart remote:
- All Lightly Used Remotes Have Been Professionally Cleared and are Ready to Program to Your Vehicle Upon Arrival