The Honda Maintenance Minder system activates the A1 code when your car requires a specific service. The system uses alphanumeric codes that contain a main item and a sub item to convey which service your Honda car requires.
In this case, the A1 service code means:
The A1 code applies to almost every modern Honda model, including the Honda Civic, Accord, Odyssey, and HR-V.
NOTE: The Honda Maintenance Minder system also informs you about your engine oil life via a percentage, to help you track when service is due. When the oil life reaches 15%, you’ll see the maintenance code on the dashboard. This indicates it’s time to schedule service soon, either at a Honda service center or with a qualified mobile mechanic.