P0604

3MZ-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

DESCRIPTION

The ECM (HV control ECU) 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 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 ignition switch to the ON position and turn the tester on.
(c) Clear the DTCs DTC Check / Clear.
(d) Turn the ignition 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 ignition switch to the ON position 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 HV CONTROL ECU