P0604

3UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0604: Random Access Memory (RAM)

DTC P0604 - Random Access Memory (RAM)

DESCRIPTION

The ECM continuously monitors its internal memory status. This self-check ensures that the ECM is functioning properly. This 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.






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 cable to the negative battery terminal.
(e) Turn the ignition switch ON.
(f) Check DTC.
OK:
P0604 is not present.
NG -- REPLACE ECM
OK -- CHECK FOR INTERMITTENT PROBLEMS