Yankee last month heavily implied the new J-15D has a more capable electronic warfare suite than J-16D mostly due to its consistent need to face Aegis combat systems, which has few peers on land with similar capabilities. Apparently the folding wing design necessitated changes internally, but that does not really answer your question about jamming pods.
J-16D is obviously also no slouch either of course, as the platform going all out in training exercises supposedly presented a much greater challenge for Type 055 versus any encounters they had with the EA-18G Growler according to Yankee early this year. He also indicated this comparison obvious comes with the huge caveat that PLAN warships did not face all of the capabilities of the EA-18G Growler.
J-15D capability requirements being higher than J-16D capability requirements does make sense in my opinion too. Amongst the four main services of the military not counting the PLARF, only the PLAN has the possibility of fighting a peer military without support from the other services. When operating from the Liaoning and the Shandong, J-15D would also expect to get much less support from early warning assets compared to J-16D operating directly from land bases. Recent information about the J-35 being more capable and more expensive versus the J-35A from discussions by Shilao also helped me reason out the decision, as the PLAN knows it could have a limited numbers of planes to fight with operating from its aircraft carrier battle group and wants to maximize capabilities of their carrier based planes even if as tradeoff costs per unit are higher.
