They are active mounts. The solenoid on the side opens up a valve to an air pocket inside the rubber. With it open the mount is softer as it just depends on the rubber. With it closed, the mount is stiffer as it also contains an air spring.
Normally the ECU will show an error code if the mounts are open circuit, but it wasn't in this case so I'll investigate that and make sure its behaving.
|