P0604

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

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

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 WHETHER DTC OUTPUT RECURS (DTC P0604)
(a) Connect Techstream to the DLC3.
(b) Turn the power switch ON (IG) and turn the tester on.
(c) Clear the DTCs DTC Check / Clear.
(d) Turn the power switch OFF and turn the tester off.
(e) Disconnect the battery negative terminal and wait for 1 minute.
(f) Connect the battery negative terminal.
(g) Turn the power switch ON (IG) and turn the tester on.
(h) Select the following menu items: Powertrain / Engine and ECT / Trouble Code.
(i) Read the DTCs.
Result:






B -- CHECK FOR INTERMITTENT PROBLEMS
A -- REPLACE ECM