Toyota RAV4 (XA40) 2013-2018 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.
- Check any other dtcs output (in addition to dtc p0604, p0606, p0607 or p0657)
- Connect the intelligent tester to the dlc3.
- Turn the ignition switch on.
- Turn the tester on.
- Select the following menu items: diagnosis / enhanced obd ii / dtc info / current codes.
- Read dtcs.
System voltage
Description
The battery supplies electricity to the ecm even when the ignition switch is
in the off position. This
power allows the ecm to store data such as dtc history, freeze frame data and ...
Starter relay circuit high
Description
While the engine is being cranked, the positive battery voltage is applied to
terminal sta of the ecm. If
the ecm detects the starter control (sta) signal while the vehicle is bein ...
Other materials:
Warning lights
Warning lights inform the driver
of malfunctions in the indicated
vehicle's systems.
Brake system warning
light*1
Brake system warning
light*1
Brake system warning
light*1
Charging system warning
light (vehicles without
12.3-inch multi-information
display)*1
Charging system warning
light (vehic ...
Vehicle speed sensor "A"
description
The speed sensor detects the wheel speed and sends the appropriate signals to
the skid control ecu.
The skid control ecu converts these wheel speed signals into a 4-pulse signal
and outputs it to the ecm
via the combination meter. The ecm determines the vehicle speed based o ...
Data list / active test
Read data list
Hint:
Using the intelligent tester's data list allows switch,
sensor, actuator and other item values to be read without
out removing any parts. Reading the data list early in
troubleshooting is one way to save time.
Connect the intelligent tester (with can vim) to the
...
