P0604

1UR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0604: Random Access Memory (RAM)

DTC P0604 - Random Access Memory (RAM)

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 a DTC immediately.






MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





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.

PROCEDURE

1. CHECK DTC
(a) Clear DTC DTC Check / Clear.
(b) Turn the engine switch off.
(c) Disconnect the cable from the negative (-) battery terminal and wait for 1 minute Service Precautions.
(d) Connect the cable to the negative (-) battery terminal Service Precautions.
(e) Turn the engine switch on (IG).
(f) Connect the Techstream to the DLC3.
(g) Turn the Techstream ON.
(h) Enter the following menus: Powertrain / Engine / Trouble Codes.
(i) Check DTC.
OK:
P0604 is not present.
NG -- REPLACE ECM
OK -- CHECK FOR INTERMITTENT PROBLEMS