P0603 Internal Control Module Keep Alive Memory (KAM) Error P0604 Internal Control Module Random Access Memory (RAM) Error P0605 Internal Control Module Read Only Memory (ROM) Error

P0603 Internal Control Module Keep Alive Memory (KAM) Error

P0604 Internal Control Module Random Access Memory (RAM) Error

P0605 Internal Control Module Read Only Memory (ROM) Error

The OBD-II trouble codes P0603, P0604, and P0605 all relate to errors in the internal memory of the vehicle's engine control module (ECM) or powertrain control module (PCM).

P0603 - Internal Control Module Keep Alive Memory (KAM) Error: This code indicates that there is an error in the ECM's ability to retain certain settings or learned values when the vehicle is turned off. This may be caused by a malfunctioning battery or alternator, or by a problem with the ECM itself.

P0604 - Internal Control Module Random Access Memory (RAM) Error: This code indicates that there is a problem with the ECM's temporary memory storage. This may be caused by a malfunctioning sensor or other component that is sending erroneous data to the ECM, or by a hardware issue with the ECM itself.

P0605 - Internal Control Module Read Only Memory (ROM) Error: This code indicates that there is an issue with the ECM's permanent memory storage. This may be caused by a faulty ECM or by a problem with the wiring or connectors that connect the ECM to the rest of the vehicle's systems.

In all three cases, it is important to have the issue diagnosed and repaired by a qualified technician. The technician will use specialized diagnostic equipment to communicate with the ECM and identify the root cause of the memory error. Depending on the cause of the problem, the technician may need to replace the ECM or repair the wiring and connectors associated with the ECM. Failure to address these issues can lead to a variety of drivability issues and may even cause the vehicle to stall or fail to start.