P0604

1UR-FSE 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. 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 standard, the ECM will illuminate the MIL and set a DTC immediately.






MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





INSPECTION PROCEDURE
HINT: Read freeze frame data using the Techstream. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1. CHECK DTC
(a) Clear DTC DTC Check / Clear.
(b) Turn the engine switch off.
(c) Disconnect the battery negative terminal and wait for 1 minute Service Precautions.
(d) Connect the battery negative terminal Service Precautions.
(e) Turn the engine switch on (IG).
(f) Connect the Techstream to the DLC3.
(g) Turn the Techstream ON.
(h) Enter the following menus: Powertrain / Engine / Trouble Codes.
(i) Check DTC.
OK:
P0604 is not present.
NG -- REPLACE ECM
OK -- CHECK FOR INTERMITTENT PROBLEMS