The invention relates to a method for controlling a waste heat recovery system (10) associated with a combustion engine (2) of a vehicle (1), the waste heat recovery system (10) comprising a working fluid circuit (12); at least one evaporator (14); an expander (16); a condenser (18); a reservoir (20) for a working fluid (WF) and a pump (22) arranged to pump the working fluid (WF) through the circuit (12), wherein the at least one evaporator (14) is arranged for heat exchange between the working fluid (WF) and a heat source (24), and wherein the waste heat recovery system (10) further comprises a cooling circuit (26) arranged in connection to the condenser (18). The method comprises the steps of: predicting (s101) a shutdown of a combustion engine (2) associated with the system (10); determining (s102) if a predetermined requirement is fulfilled; and if so reducing (s103) the temperature in the waste heat recovery system (10) prior to combustion engine shutdown. The invention also relates to a waste heat recovery system (10), a vehicle (1) comprising such a system (10), a computer program (P) and a computer program product.