tfp soundwave either doesnt sneeze (soundwave: superior. sneeze: inferior), it sounds like a cat, or you'd think a demon crawled out from the pits of the underworld.
One of three options. Take it or leave it.
Like, whooshing air sharply out of their vents in order to clear irritants- basically the same idea as anything else sneezing, but with their entire body as opposed to just their nasal area.
Big bots sneezing and sending data-pads flying.
Little bots having sneezing fits and falling out of their chairs.
Bots trying to hold in big sneezes by clamping down their plating- and then said plating just goes flying off.
Seekers flying through something irritating during a flight, sneezing right in the middle of a big complicated routine, and just kind of completely losing all the dramatic effect.