P0604

2GR-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, 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 illuminate 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 and 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

ECM RAM errors





INSPECTION PROCEDURE
HINT: 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 Freeze Frame Data.

PROCEDURE

1. READ DTC OUTPUT (DTC P0604)
(a) Clear the DTC.
(b) Turn the ignition switch OFF.
(c) Disconnect the battery negative terminal and wait for 1 minute.
(d) Connect the battery negative terminal.
(e) Turn the ignition switch on (IG).
(f) Enter the following menus: Powertrain / Engine / Trouble Codes.
(g) Read the DTCs.
OK:
P0604 is not present.
NG -- REPLACE ECM
OK -- CHECK FOR INTERMITTENT PROBLEMS