P0604

2AZ-FXE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0604: Internal Control Module Random Access Memory (RAM) Error
P0604 - Internal Control Module Random Access Memory (RAM) Error

DESCRIPTION

The ECM (included in the hybrid vehicle control ECU) 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 a DTC immediately.





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





INSPECTION PROCEDURE

HINT
Read freeze frame data using the Techstream. The ECM (included in the hybrid vehicle control ECU) records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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 OTHER DTC OUTPUT (IN ADDITION TO DTC P0604)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the tester on.

(d) Clear the DTC.

(e) Turn the power switch off and turn the Techstream off.

(f) Disconnect the Techstream.

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

(h) Connect the battery negative terminal.

(i) Connect the Techstream to the DLC3.

(j) Turn the power switch on (IG).

(k) Turn the Techstream on.

(l) Enter the following menus: Powertrain / Engine / Trouble Code.

(m) Read the DTCs.

Result:





B -- REPLACE HYBRID VEHICLE CONTROL ECU Removal

A -- CHECK FOR INTERMITTENT PROBLEMS Check for Intermittent Problems