Circuit Description
WARNING: This page is about a different car, the 2006 Suzuki Verona. However, it is still accessible from the selected car via links, so may be relevant.
A normal function of the Transaxle Control Module (TCM) programming is to perform an internal check that verifies the integrity of the RAM memory allocations.
The DTC P0604 sets when the Random Access Memory (RAM) is not operating correctly when checked on initialization. An area of RAM is failed a read/write test.