Toyota Sienna Service Manual: 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
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:
Installing child restraint
systems
General information
Pay attention to the specifications and the operating
and safety information of the child restraint
system manufacturer when selecting, installing,
and using child restraint systems.
Safety information
Warning
The protective effect of child restraint systems
and their fastening ...
Disassembly
1. SEPARATE REAR DRIVE SHAFT INBOARD JOINT BOOT CLAMP
(a) Using a screwdriver, remove the 2 rear drive shaft
inboard joint boot clamps as shown in the
illustration.
2. SEPARATE REAR DRIVE SHAFT INBOARD JOINT
BOOT
(a) Separate the rear drive shaft inboard joint boot from
the inboard joint ...
Capacity and distribution
Cargo capacity depends on the total weight of the occupants.
(Cargo capacity) = (Total load capacity) - (Total weight of occupants)
Steps for Determining Correct Load Limit
Locate the statement “The combined weight of occupants and
cargo should never exceed XXX kg or XXX lbs.” on your ...
