P0604

2ZR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0604: Random Access Memory (RAM)
P0604 - Random Access Memory (RAM)

MONITOR 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 the DTC immediately.





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





CONFIRMATION DRIVING PATTERN





- Connect the Techstream to the DLC3.

- Turn the ignition switch to ON and turn the Techstream on.

- Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).

- Turn the ignition switch off and wait for at least 30 seconds.

- Turn the ignition switch to ON and turn the Techstream on [A].

- Wait 16 seconds or more.

- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [B].

- Read the DTCs.

HINT
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
- Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

- Input the DTC: P0604.

- Check the DTC judgment result.





HINT
If the judgment result shows ABNORMAL, the system has a malfunction.

- If the test result is INCOMPLETE or UNKNOWN and no DTC is output, perform a universal trip and check for permanent DTCs DTC Check / Clear.

HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.
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. READ OUTPUT DTC (DTC P0604)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear DTC DTC Check / Clear.

(e) Turn the ignition switch to OFF and turn the tester OFF.

(f) Disconnect the tester.

(g) Disconnect the cable from the battery negative (-) terminal and wait for 1 minute.

(h) Connect the cable to the battery negative (-) terminal.

(i) Connect the tester to the DLC3.

(j) Turn the ignition switch to ON.

(k) Turn the Techstream on.

(l) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(m) Read the DTCs.

Result:





B -- REPLACE ECM Removal

A -- CHECK FOR INTERMITTENT PROBLEMS