When a car is impounded because it contains drugs, the Chicago Police Department decides if the car should be forfeited. If the police decide the car should be forfeited, you cannot reclaim it. If the police do not say it should be forfeited, it will be approved for release. It can take several days for the police to decide whether to release the car.

You can retrieve your car by paying a fine at the Department of Revenue. Note that as the owner of the car, you are responsible for the drug violation. It doesn't matter whether you were present when the car was impounded. 

For the steps to retrieve your car, please refer to Getting back an impounded car - Chicago.