P0604

2AZ-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 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 OTHER DTC OUTPUT (IN ADDITION TO DTC P0604)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn the Techstream on.
(d) Clear the DTC DTC Check / Clear.
(e) Turn the ignition switch off.
(f) Disconnect the battery negative terminal and wait for 1 minute.
(g) Connect the battery negative terminal.
(h) Turn the ignition switch to the ON position.
(i) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(j) Read the DTCs.
Result:





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