P0604

2GR-FE ENGINE CONTROL: 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, internal circuits, and output signals sent to the throttle actuator. This self-check ensures that the ECM is functioning properly. If any malfunction is detected, the ECM will set the appropriate DTC and illuminates the MIL.
The ECM memory status is diagnosed by internal "mirroring" of the main CPU and the sub CPU to detect Random Access Memory (RAM) errors. The 2 CPUs also perform continuous mutual monitoring. The ECM illuminates the MIL and sets a DTC if: 1) outputs from the 2 CPUs are different or deviate from the standards, 2) the signals sent to the throttle actuator deviate from the standards, 3) a malfunction is found in the throttle actuator supply voltage, and 4) any other ECM malfunction is found.





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





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 procedure) DTC Check / Clear [A].
4. Wait 16 seconds or more.
5. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
6. Input the DTC: P0604.
7. Check the DTC judgment result [B].





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

8. If the test result is UNKNOWN, enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
9. Read Pending DTCs.
HINT: If a pending DTC is output, the system is malfunctioning.

10. If the test result is INCOMPLETE or UNKNOWN and no pending 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

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

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 the DTCs DTC Check / Clear.
(e) Turn the ignition switch off.
(f) Turn the Techstream off.
(g) Disconnect the Techstream.
(h) Disconnect the cable from the negative (-) battery terminal and wait for 1 minute.
(i) Connect the cable to the negative (-) battery terminal.
(j) Connect the Techstream to the DLC3.
(k) Turn the ignition switch to ON.
(l) Turn the Techstream on.
(m) Enter the following menus: Powertrain / Engine / Trouble Codes.
(n) Read the DTCs.
Result:





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