I just bought a 2004 TSX with 50k miles on it and had the typical VSA + (!) light on issue. It turns out the VSA neutral position sensor was having issues. I think I've fixed it now so I thought I'd do a quick write up in case anyone else is in the same boat.
If anyone knows what could cause the VSA neutral sensor to need re-calibration please chime in.
If anyone knows what could cause the VSA neutral sensor to need re-calibration please chime in.

- Read the codes
- To do this short pin 4 to pin 9 on the 16P data link connector (DLC) next to the hood release.
- Without pressing the brake, turn the ignition to "ON"
- The ABS light should flash back the codes (long flashes for 10s digit and short flashes for 1s digit). If there are multiple codes it will keep cycling through them
- I had 3 codes: 51- Motor Lock, 61- High Voltage, and 84- VSA Sensor neutral position
- Clear the codes
- With pins 4 and 9 still jumped, and the brake pressed switch on the ignition
- When the ABS light turns off, release the brake
- When the ABS light turns back on, press and hold the brake
- One it goes off again you can release the brake again. If the ABS light flashes twice, the codes have been cleared.
- At this point I test drove the car and then rechecked the error codes. This time only 84 showed up so I looked that up in the manual
- Sensor Calibration
- At this point I followed the procedure in the manual to "rememorize" the VSA neutral sensor position
- Connect pin 9 from the DLC to ground (I had to jump to the negative terminal of the battery to get a good connection - I don't know which of the pins on the DLC is ground)
- Turn the ignition to "ON" and when the ABS light turns off (after about 2 seconds) press and release the VSA button
- When the ABS light comes back on, press the VSA button again
- At this point you'll see things flash a few times and all the VSA and other warning lights should turn off
- I went for a test drive and everything was good- VSA button working as it should