I found this from a pdf. Google search 98-011 service bulletin. The first pdf has the information. The battery could be dead too. Do you have another key that you can try?
Here is the info from the pdf.
The system accepts up to three transmitters. The
transmitter codes are stored in a stacking-type
memory. If a fourth transmitter code is programmed,
the code for the first transmitter is erased.
• Entering the programming mode cancels all learned
transmitter codes, so none of the previously
programmed transmitters will work. You must
reprogram all of the transmitters once you are in the
• You must complete steps 1–6 within 4 seconds of
the previous step to keep the system from exiting the
1. Turn the ignition switch to ON (II).
2. Press the “Lock” or “Unlock” button on one of the
transmitters. (An unprogrammed transmitter can be
used for this step.)
3. Turn the ignition switch to LOCK (0).
4. Repeat steps 1, 2, and 3 two more times using the
same transmitter used in step 2.
5. Turn the ignition switch to ON (II).
6. Press the “Lock” or “Unlock” button on the same
transmitter. Make sure the power door locks cycle
to confirm that the system is in programming mode.
7. Within 10 seconds, press the “Lock” or “Unlock”
button on each transmitter. Make sure the power
door locks cycle after you press each transmitter
button to confirm that the system accepted the
8. Turn the ignition switch to LOCK (0) to exit the
Let us know how this works out.
2005 Acura TSX MT