P0604

2ZR-FE ENGINE CONTROL: SFI SYSTEM: P0604: Random Access Memory (RAM)
P0604 - Random Access Memory (RAM)

MONITOR 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 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 the 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. 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 DTC DTC Check / Clear.

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

(f) Disconnect the Techstream.

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

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

(i) Connect the Techstream to the DLC3.

(j) Turn the ignition switch to ON.

(k) Turn the Techstream on.

(l) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(m) Read the DTCs.

Result:





B -- REPLACE ECM Removal

A -- CHECK FOR INTERMITTENT PROBLEMS Check for Intermittent Problems