CarKeyErrorCode in the CarKey framework

I have a question regarding CarKeyErrorCode in the CarKey framework.

I plan to use the following methods in the CarKey framework:

1. CarKeyRemoteControl.start
2. CarKeyRemoteControlSession.vehicleReports
3. CarKeyRemoteControlSession.perform
4. RemoteKeylessEntryAction.ExecutionRequest.results

Each of the above methods throws an Error. Are these different from CarKeyErrorCode? Is CarKeyErrorCode only used in CarKeyRemoteControlSessionDelegate.remoteControlSession(_:didInvalidateWithError:)?

If methods 1-4 do not return CarKeyErrorCode, what kind of Error do they return?

Thank you in advance.