Not necessarily. The car could accept future codes, but not an older one. Assume codes A through Z, you've used A, B, and C, then when out of range of the vehic

Not necessarily. The car could accept future codes, but not an older one. Assume codes A through Z, you've used A, B, and C, then when out of range of the vehicle you send codes D and E (Or these are jammed and stored for later use). That afternoon, you return to your car and issue code F, now codes D and E are no longer accepted (Until you get so far down the line that looping becomes a concern)