P0604

1GR-FE ENGINE CONTROL: SFI SYSTEM: P0604: Internal Control Module Random Access Memory (RAM) Error
P0604 - Internal Control Module Random Access Memory (RAM) Error

DESCRIPTION

The ECM continuously monitors its own internal memory status, internal circuits, and output signals transmitted to the throttle actuator. This self-check ensures that the ECM is functioning properly. If any malfunction is detected, the ECM stores the appropriate DTC and illuminates the MIL.

The ECM memory status is diagnosed by internal mirroring of the main CPU and sub CPU to detect Random Access Memory (RAM) errors. The two CPUs also perform continuous mutual monitoring. The ECM illuminates the MIL and stores a DTC if: 1) outputs from the 2 CPUs are different or deviate from the standard, 2) the signals sent to the throttle actuator deviate from the standard, 3) a malfunction is found in the throttle actuator supply voltage, or 4) any other ECM malfunction is found.





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS

ECM RAM Errors





CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

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

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

4. Turn the Techstream off.

5. Turn the ignition switch off.

6. Disconnect the Techstream.

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

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

9. Connect the Techstream to the DLC3.

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

11. Wait 16 seconds or more.

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

13. Read the DTCs.

HINT
* If a DTC is output, the system is malfunctioning.
* If a DTC is not output, perform the following procedure.

14. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

15. Input the DTC: P0604.

16. Check the DTC judgment result.





HINT
* If the judgment result shows NORMAL, the system is normal.
* If the judgment result shows ABNORMAL, the system has a malfunction.

17. If the test result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
* If a permanent DTC is output, the system is malfunctioning.
* If no permanent DTC is output, the system is normal.

INSPECTION PROCEDURE

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 WHETHER DTC OUTPUT RECURS (P0604)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Code.

(e) Read DTCs.

Result





B -- CHECK FOR INTERMITTENT PROBLEMS Check for Intermittent Problems

A -- REPLACE ECM Removal