No.
Consciousness is not epiphenomenal
The Evolutionary Argument
The theory of evolution by Natural Selection is supposed to answer Paley's question: how is it that complex, well-adapted phenomena exist? Paley's answer was, famously, that there must have been a Divine Creator. Darwin's response is that, given heritable variation in fitness, such complexity and adaptedness are not surprising.
The phenomenon of consciousness cries out for explaining, so it must have been selected for, but in order to have been selected for, it had to have made a difference. Ergo, it is not epiphenomenal, Q.E.D.
"[Epiphenomenalism] supposes some thing to exist in nature which has nothing to do, no purpose to serve, a species of noblesse which depends on the work of its inferiors, but is kept for show and might as well, and undoubtedly would in time be demolished" (Alexander, p. 8)
Response:
Being causally inefficacious is not a sufficient condition for being selected against. If there are no costs and no benefits to a trait, selection can neither favour nor cull it, relative to its competitors.
More importantly, some traits are unavoidable accompaniments of selection-relevant traits. The polar bear's coat was selected for being warm, not, presumably for being heavy, even though (given the constraints of the initial conditions), only heavy coats are warn. (See Jackson (1982), and Sober (1984).)
There may be nothing wrong with adaptationism as a research methodology, but the real details are, well, in the details. Synchronic considerations cannot be left out. And they are what would answer the question at hand.