BMW Repair: abs warning light, abs light, left front tire

Question
About once every couple weeks the abs light will come on while driving.  The light will remain on for the rest of the trip.  But, will not come back on the next time the car is driven.

The brakes on the car were serviced approximately 4 months ago and work fine.  

Are there any things I can check to identify a potential problem, before I take it in and have to pay a service fee?

thanks,

Answer
not really, check the connections for the abs sensors on the right rear tire and left front tire. when the brakes were done, it is possible that the brake pad warning sensor and abs sensor connectors got mixed up. otherwise it needs to be checked by the dealer