Hybrid battery cooling system maintenance warning

The maintenance warning light came on a couple weeks ago. Last week I called the local dealership, (unfortunately only one in this town with not a good reputation) and they told me to make sure the cooling vents were not obstructed. I already knew they were not, but I went to the backseat and checked to make sure, all clear. The maintenance warning message is still there. This place charges way too much for diagnostic service, and I don't know who else to trust in this town because my own mechanic who has been handling basic stuff doesn't do it. Since I know there's nothing obstructing the ventilation of the hybrid battery pack, the message probably just has to be turned off, and I want someone who's not going to rip me off for something that simple. Is there some way for me to reset that message myself, just to see if it comes back on and is possibly for real, or do I have to take it in? Thanks in advance!