We would suggest one minor thing first... drop the "Icarus" name... that's Milky way mythology. Doesn't make any sense in Star Wars. Considering the vastness of the Star Wars universe, it should not be hard to find a name that is from the lore of that universe.

As for what happens? Perhaps a plethora of small things adding up?

Former battle-damage to hull and some secondary systems
Some slimy Hutt supplied some essential part of the engines/hyperdrive, and skimped out on something, which then breaks down.
Someone or something unknown/unidentified betrays the crew, sabotaging another system or triggering automated self-destruct.
In the rush to get back, they made a mistake on route calculation, passing too close to a gravity well. When added with above reasons, that overloads something.