I lost one of my original transponder keys and didn’t feel like paying the dealer to get a new one (let alone the programming fee). Anyways, stumbled on a Toyota Sienna post about getting a transponder key and programming it yourself (caveat--you need to have the original master key).
Anyways, I thought I would do the same for the 4Runner. I did the following:
1. Bought a new blank Toyota transponder from eBay (about $12, it has a dot near base the of key shaft; see picture). Although advertised as an “OEM Toyota key”, it appears to be a Chinese clone (different metal color). Toyota part number: 89785-60160
2. Have it cut by your local locksmith ($5). Of note, my locksmith did chuckle at me and mentioned that he would be available to program the key for $50 as he wasn’t aware of any method of key programming without the proper computers.
Programming Instructions
1. Sit in your car with all doors closed (and doors unlocked)
2. Insert/remove your original master key to ignition 4 times (do not turn key)
3. Insert master key and leave it in the ignition
4. Open and close driver side door 6 times. Leave driver’s door closed on 6th cycle
5. Remove master key from key cylinder
6. Insert your new cut transponder key and turn to ON. The red immobilizer light (just above your climate control LCD info panel) will slowly blink. Once the immobilizer light stays off (about 60-80 seconds), you can remove the new key
7. Insert original master key and turn key to ON, then OFF to finish programming cycle
8. Try your new transponder key to start up the car.