P0604

1GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0604: Internal Control Module Random Access Memory (RAM) Error

DTC P0604 - Internal Control Module Random Access Memory (RAM) Error

MONITOR DESCRIPTION

The ECM continuously monitors its internal memory status. This self-check ensures that the ECM is 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 standards, the ECM will illuminate the MIL and set a DTC immediately.






MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





INSPECTION PROCEDURE

PROCEDURE

1. CHECK DTC
(a) Clear DTC.
(b) Turn the ignition switch off.
(c) Disconnect the cable from the negative battery terminal and wait for 1 minute.
(d) Connect the negative battery terminal.
(e) Turn the ignition switch to ON.
(f) Check DTC.
OK:
P0604 is not present.
NG -- REPLACE ECM
OK -- CHECK FOR INTERMITTENT PROBLEMS