
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
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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.

System voltage
Starter relay circuit highFront airbag sensor
Components
On-vehicle inspection
Check front airbag sensor (vehicle not
involved in collision and airbag not
deployed)
Perform a diagnostic system check (see page rs-
49).
Check front airbag sensor (vehicle
involved in collision and airbag has not
deployed)
Perfo ...
If the shift lever cannot
be shifted from p
If the shift lever cannot be shifted with your foot on the brake
pedal, there may be a problem with the shift lock system (a system
to prevent accidental operation of the shift lever). Have the
vehicle inspected by your toyota dealer immediately.
The following steps may be used as an emergency ...
Second brake piston
Components
Disassembly
Remove 2nd brake piston return spring sub-assembly
Place sst on the return spring and compress.
Using a screwdriver, pry out the snap ring.
Remove the piston return spring.
Inspect 2nd brake piston return spring sub-assembly (see page ax-223)
...