Anecdotal sources suggest that A12 service code means Oil and filter change, a tire rotation and air filter change. A12 means the A1 and A2 services are due, hence A12.
You can also check the items in the Maintenance Section:
Maintenance Minder A Scheduled Maintenance Recommended service for your 2004 Acura TL:
Replace engine oil*1
*1: If the message, "SERVICE DUE NOW" does not appear more than 12 months after the display is reset, change the engine oil every year.
Independent of the maintenance messages in the Multi-Information Display, replace the brake fluid every 3 years.
Taking good care of your vehicle can make the difference between being the proud owner of a good looking, long lasting, reliable machine, and saying goodbye to a rusty, faded-paint jalopy that fell apart or broke down long before it was designed to. Here are some tips on how to keep your car in top-notch condition shared by kbb.com.