Memory repair method and apparatus based on error code tracking

A memory module is disclosed that includes a substrate, a memory device that outputs read data, and a buffer. The buffer has a primary interface for transferring the read data to a memory controller and a secondary interface coupled to the memory device to receive the read data. The buffer includes error logic to identify an error in the received read data and to identify a storage cell location in the memory device associated with the error. Repair logic maps a replacement storage element as a substitute storage element for the storage cell location associated with the error.