Steps to search through all of the codes in your remote if an obvious one is not listed.
1. Cover the end of the TiVo remote control with your hand.
2. Hold down the TiVo and TV POWER buttons simultaneously until the red (or amber) light on the remote control remains on.
3. Remove your hand from the end of the TiVo remote control.
4. Enter code 0999.
5. After you enter the code, the red (or amber) light will flash three times and then remain on.
6. Press CHANNEL UP once every two seconds. This will test hundreds of codes, one by one.
IMPORTANT: Do not go any faster than this or you may skip over a code that works.
If you press CHANNEL UP and your TV turns off, press ENTER to select the code. Press the TV POWER button to test the code. If your TV turns on, you have successfully programmed the remote.
If you cycle through all the codes, the red LED will go off, indicating that you have tried all the codes. If this happens, or if you selected a code but the TV does not respond to the test, try again, to make sure you did not skip over your code by going too fast.
Link: Full support article on locating program codes