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Toyota Sienna Service Manual: Internal Control Module Random Access Memory (RAM) Error

Toyota Sienna Service Manual / Engine / 2Gr-fe engine control system / Sfi system / Diagnostic trouble code chart / Internal Control Module Random Access Memory (RAM) Error

Internal Control Module Random Access Memory (RAM) Error

DESCRIPTION

The ECM continuously monitors its own internal memory status, internal circuits, and output signals transmitted to the throttle actuator. This self-check ensures that the ECM is functioning properly. If any malfunction is detected, the ECM sets 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 two CPUs also perform continuous mutual monitoring. The ECM illuminates the MIL and sets a DTC if: 1) outputs from the two 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.

DESCRIPTION

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS

INSPECTION PROCEDURE

Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. 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.

1 CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0604)

(a) Connect the intelligent tester to the DLC3.

(b) Turn the ignition switch to the ON position.

(c) Turn the tester on.

(d) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

(e) Read DTCs.

Result

REPLACE ECM

System Voltage
MONITOR DESCRIPTION The battery supplies electricity to the ECM even when the ignition switch is off. This power allows the ECM to store data such as DTC history, freeze frame data and fuel tr ...

ECM / PCM Processor
DESCRIPTION The ECM continuously monitors its internal processors (CPUs), A/F sensor transistors and heated oxygen sensor (HO2S) transistors. This self-check ensures that the ECM is functionin ...

Other materials:

Ignition Switch Circuit
DESCRIPTION The Multiplex network body ECU receives the ACC and IG signals from the ignition switch. WIRING DIAGRAM INSPECTION PROCEDURE 1 READ VALUE OF INTELLIGENT TESTER Connect the intelligent tester to DLC3.  Turn the ignition switch ON and push the intelligent tester main ...

Canceling the power back door system (vehicles with power back door)
Turn the main switch off to disable the power back door system. Off On* *: The orange line at the top of the switch indicates that the power back door system is on. Luggage compartment light The luggage compartment light turns on when the back door is opened with the luggage ...

Power Window can be Operated After Ignition Switch is Turned OFF Even if Operative Conditions are not Met
DESCRIPTION The multiplex network body ECU controls power supplied to the power window master switch and each regulator switch continuously for 45 seconds after the ignition switch is turned OFF unless the front doors have been opened, so that the power window can be operated during this peri ...

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