General Motors has issued a service bulletin directing dealers to provide a free remedy for certain 2012 and 2013 model-year Chevrolet Volt cars that have insufficient battery coolant levels.

In these extended-range electric vehicles, the battery coolant volume can fall below specification after air in the system is purged. If the coolant falls below recommended levels, the vehicle will display a warning message – “Service High Voltage Charging System” – in the driver information center. The system then may be unable to charge the car until the coolant is filled to the proper level.

“Dealers are instructed to top off the coolant to recommended levels, if needed, and the customer should be able to return to normal charging operation,” said Kevin M. Kelly, GM manager of electrification technology communications.

To learn whether their car is involved in the service campaign, Volt owners can contact their local dealer and provide the VIN.