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 (included in the hybrid vehicle 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 the Techstream to the DLC3.
(b) Turn the power switch on (IG) and turn the Techstream on.
(c) Clear the DTCs DTC Check / Clear.
(d) Turn the power switch off and turn the Techstream 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 Techstream on.
(h) Select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
(i) Read the DTCs.
Result:






B -- CHECK FOR INTERMITTENT PROBLEMS
A -- REPLACE HYBRID VEHICLE CONTROL ECU