* Simple: The car's engine suddenly malfunctioned, leaving us stranded on the highway.
* With Cause: The power outage was caused by a malfunction in the transformer.
* Figurative: His plan malfunctioned when his key witness failed to show up.
* Formal: The report concluded that the accident was due to a malfunction of the braking system.
* Informal: My phone is malfunctioning again - I can't even make a call!
You can also use "malfunction" as a noun:
* The technician was called in to investigate the malfunction**.
* The malfunction of the elevator caused a delay in the building's evacuation.