Essential component of the PAM complex, a complex required for the translocation of transit peptide-containing proteins from the inner membrane into the mitochondrial matrix in an ATP-dependent manner. In the complex, it is required to stimulate activity of mtHSP70 (SSC1). Homodimer and heterodimer with PAM16/TIM16. Homodimerization may not be relevant in vivo, while heterodimerization is essential for activity regulation of mtHSP70. Component of the PAM complex, at least composed of mtHsp70, MGE1, TIM44, PAM16, PAM17 and PAM18/TIM14. Interacts directly with mtHsp70. Interacts directly with TIM17 subunit of the TIM23 complex. The J domain is essential for co-chaperone activity and mediates the heterodimerization with the J-like domain of PAM16. Belongs to the TIM14 family.