The device was thrown at the vehicle in the early hours of Sunday morning in the castlemara area of the town.
Stewart Dickson MLA said: “Those behind this reckless attack have nothing to offer our society and I must condemn their actions.
“There can never be any justification for attacking the police, who are carrying out their job aiming to keep everyone safe from harm.
“We are very fortunate that an officer was not injured or worse and I would urge anyone with information to contact the PSNI as soon as possible.”