I have the same problem, DVD player is in Black and white wilhen connected to my TCL Roku TV, S-Series. How do I fix this? The color is fine when watching cable television, just lose color when watching a DVD.
I did some digging, and many DVD players use what's called luma-based analog component video. In essence, it has a "luma" cable, which provides black and white brightness information, and a "chroma" cable, which provides color information. It's likely that your "chroma" connection somehow got loose/disconnected.