Toyota RAV4 Service Manual: Vc output circuit
Description
The ecm constantly generates 5 v power from the battery voltages supplied to
the +b (batt) terminal to
operate the microprocessor. The ecm also provides this power to the sensors
through the vc output
circuit.

When the vc circuit is short-circuited, the microprocessor in the ecm and
sensors that are supplied with
power through the vc circuit are inactivated because the power is not supplied
from the vc circuit. Under
this condition, the system does not start up and the mil does not illuminate
even if the system
malfunctions.
Hint:
Under normal conditions, the mil is illuminated for several seconds when the
ignition switch is first turned
on. The mil goes off when the engine is started.
Wiring diagram

Inspection procedure
- Check mil
- Check that the malfunction indicator lamp (mil) lights
up when turning the ignition switch on.
Ok:
mil lights up

- Check communication between intelligent tester and ecm
- Connect the intelligent tester to the dlc3.
- Turn the ignition switch on and tester on.
- Check the communication between the tester and ecm.


- Check mil (throttle position sensor)
- Disconnect the b3 throttle body connector.
- Turn the ignition switch on.
- Check the mil.

- Reconnect the throttle body connector.

- Check mil (accelerator pedal position sensor)
- Disconnect the a4 accelerator pedal position sensor
connector.
- Turn the ignition switch on.
- Check the mil.

- Reconnect the accelerator pedal position sensor
connector.

- Check mil (canister pump module)

- Disconnect the s3 canister pump module connector.
- Turn the ignition switch on.
- Check the mil.

- Reconnect the canister pump module connector.

- Check mil (battery current sensor)
- Disconnect the b29 battery current sensor connector.
- Turn the ignition switch on.
- Check the mil.

- Reconnect the battery current sensor connector.

- Check harness and connector
- Disconnect the b3 throttle body connector.
- Disconnect the a4 accelerator pedal position sensor
connector.
- Disconnect the s3 canister pump module connector.
- Disconnect the b29 battery current sensor connector.
- Disconnect the a9 and b30 ecm connectors.
- Measure the resistance.
Standard resistance (check for short)

- Reconnect the throttle body connector.
- Reconnect the accelerator pedal position sensor
connector.
- Reconnect the canister pump module connector.
- Reconnect the battery current sensor connector.
- Reconnect the ecm connectors.

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