Catalyzes the reversible synthesis of acetylcholine (ACh) from acetyl CoA and choline at cholinergic synapses (By similarity). Required in SIA sublateral cholinergic motor neurons for a left-right turning behavior that occurs during the lethargus phase of the normal sleep process called 'flipping' (PubMed:28244369). During 'flipping' animals rotate 180 degrees about their longitudinal axis (PubMed:28244369). acetyl-CoA + choline = acetylcholine + CoA Expressed in SIA, SIB and SMB sublateral motor neurons. RNAi-mediated knockdown in SIA sublateral motor neurons results in abnormal sleep behavior whereby larvae display a defect in 'flipping,' which is a left-right turning behavior that occurs during sleep. Belongs to the carnitine/choline acetyltransferase family.