Toyota Sienna Service Manual: Internal Control Module Random Access Memory (RAM) Error
DTC P0604 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.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
ECM RAM errors:
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)
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch to the ON position.
- Turn the tester on.
- Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
- Read DTCs.
Result
REPLACE ECM
System Voltage
DTC P0560 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 ...
ECM / PCM Processor
DTC P0606 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 ...
Other materials:
Throttle Actuator Control Motor Current Range / Performance
DESCRIPTION
The ETCS (Electronic Throttle Control System) has a dedicated power supply
circuit. The voltage (+BM)
is monitored and when it is low (less than 4 V), the ECM determines that there
is a malfunction in the
ETCS and cuts off the current to the throttle actuator.
When the volt ...
Sleep Operation Failure of Occupant Classification
ECU
DTC B1796 Sleep Operation Failure of Occupant Classification
ECU
DESCRIPTION
During sleep mode, the occupant classification ECU reads the condition of
each sensor while the ignition
switch is off.
In this mode, if the occupant classification ECU detects an internal
malfunction, DTC B1796 ...
Pressure Control Solenoid "D" Electrical (Shift
Solenoid Valve SLT)
DESCRIPTION
The linear solenoid valve (SLT) controls the transmission line pressure for
smooth transmission operation
based on signals from the throttle position sensor and the vehicle speed sensor.
The ECM adjusts the
duty cycle of the SLT solenoid valve to control hydraulic line pressure co ...
