Sounds like there's a problem with the Coolant Temp Sensor circuit. This is one of those PGM-FI codes that also affects the tranny. Problems in that circuit can cause the tranny lock-up clutch not to engage.

Make sure the sensor is connected. If there are no loose connections, then check the sensor itself before you spend your money and replace it. If the sensor checks out okay, then there may be a wiring problem.

If you're not sure how to check the sensor, go to the Acura Vigor Club and do a search on "temp sensor." I wrote a few different articles about checking these sensors.

Just so you don't get confused, they're called "ECT" and "TW" sensors, depending on the particular Honda manual you're using. Different names for the same sensor. Confusing!