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DTC P0604: Internal Control Module Random Access Memory (RAM) Error [09/2014 - 10/2015]: Description

WARNING: This page is about a different car, the 2015 Lexus GS 350. However, it is still accessible from the selected car via links, so may be relevant.

The ECM continuously monitors its internal memory status. This self-check ensures that the ECM functioning properly. It is diagnosed by internal "mirroring" of the main CPU and sub CPU to detect the Random Access Memory (RAM) errors. If outputs from these CPUs are different and deviate from the standard, the ECM will illuminate the MIL and set a DTC immediately.

DTC DTC Setting Condition Trouble Area
P0604 ECM RAM errors (Main CPU and sub CPU mirroring failure) (1 trip detection logic). ECM
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