Question provides too few details on the universe it's trying to describe, making it difficult to answer.
Currently we, as a spacefaring species would face two distinct, yet connected, challenges: travelling and/or communicating through the space-time continuum. In other words, we are limited to slower-than-light speeds. In addition, the distances aren't making it any easier.
Consider radio transmitter - it can be used to communicate over vast distances on Earth, using (relatively) weak signal, because it's bouncing off the various layers of the atmosphere (typically ionosphere) or Moon (but that's atypical). Normally we use satellite network (sending signals from one point to another by passing it between the satellites if distances are great). There is no ionosphere in space, and there are a lot of other factors that actually dampen signals a great deal in interplanetary and/or interstellar space - for example frame-dragging effect of a sun, number and movement of gas giants (if any) or other celestial bodies, type of a star and it's emissions...
So, in order for our castaways to be able to send emergency signals they need one or more of the items off the list:
- FTL mode of interstellar communication or
- Be "close" to the interstellar route and FTL travel is not preventing receiving STL communications
- Powerful transmitter
- Know their location in terms of galaxy
- Know the location of the target of their transmission
If our castaways veered off course and crashed on an uninhabited planet in a binary star system, on the wrong half of the planet and in the process losing ship's power plant they may have to first relocate to a spot from which their signal will reach the part of the galaxy they need, restore their power-generation capabilities... Then their signal may be sub-light only and takes 50 years to reach the travel lanes and they have to have just a tiny window where they and the spot they send signal to have unobscured (by other planets, for example) Line-Of-Sight - yes, some sort of anti-conjunction of planets... Their star needs to go into the calm period of it's cycle, emitting much less solar wind or other radiation...
There are ways, but you need to decide what your conditions are.