How can you check an ignition coil?

Very Carefully!

Modern electronic ignition systems can operate at 100,000 volts so will bite you hard if you become part of the circuit.

You can also damage or spike any electronic management system or control boxes on the car.

To check the coil you will need some kind of meter or measuring device. These tend to be part of an engine diagnostics pack so coupled with the above warnings I would recommend using some kind of dealer. I am not saying that a competent DIY mechanic cannot do it, but if you need to ask you probably do not currently have the skills and its not one to learn on!!

In the old days. with pre electronic management systems, we used to take off an ignition lead put in an old spark plug, use insulated grips to hold it against the block, turn the engine over and look how strong the spark was. You would probably kill yourself and the car doing this now!