From time to time resetting the ecu is needed, perhaps if you have a light on the dash sometimes a ecu reset can clear the error or maybe you have modified the air/fuel mixture with aftermarket parts in some way.

Anyway i found this guide, before anyone uses it can someone please step in and say if this guide is suitable and a good method on UK cars? As i believe it is a US guide.

http://itisfresh.com/how-to-reset-ecu-acura-nsx.html

The guide is interesting in the way they let it warm up first and then reset it, makes sense. As the ecu is learning during normal driving and tempreture rather than a cold engine.

Is the other method to disconnect the battery for 15min? This recently happened to mine purely by accident as i had let it sit for 3 weeks and the battery was dead :O