Catalyzes the 2-hydroxylation of not only racemic phytanoyl- CoA and the isomers of 3-methylhexadecanoyl-CoA, but also a variety of other mono-branched 3-methylacyl-CoA esters (with a chain length of at least seven carbon atoms) and straight-chain acyl-CoA esters (with a chain length longer than four carbon atoms) (PubMed:10744784, PubMed:12031666, PubMed:12923223, PubMed:9326939). Does not hydroxylate long and very long straight chain acyl-CoAs or 2-methyl- and 4-methyl- branched acyl-CoAs (PubMed:10744784, PubMed:12923223). {ECO:0000269|PubMed:10744784, ECO:0000269|PubMed:12031666, ECO:0000269|PubMed:12923223, ECO:0000269|PubMed:9326939}. This is the function of PHYH (phytanoyl-CoA 2-hydroxylase, Ensembl gene identifier ENSG00000107537).