Internal Control Module Memory Check Sum Error
Indicates that the PCM received an invalid checksum from the Engine Control Module (ECM). The ECM constantly checks its memory for errors and records if any are detected. The PCM periodically checks with the ECM to ensure there have not been any errors. If the PCM detects an error with the ECM's memory, the P0601 code will be set. The most common cause of the code setting is a software error in either the PCM or ECM, or a loss of communication between the PCM and ECM, due to a fault with the wiring harness or connectors between the two control modules.
