DTC P0604: Control Module Random Access Memory: Description
WARNING: This page is about a different car, the 2001 Cadillac Seville, 2001 Cadillac Eldorado, and 2001 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
Powertrain Control Module (PCM) copies program information that is stored in the Electrically Erasable Programmable Read Only Memory (EEPROM) to the Random Access Memory (RAM). This allows PCM to work with, and update the information. PCM tests all areas of the RAM. If PCM detects an error in any area of the RAM, DTC P0604 will set.