Toyota Sienna Service Manual: No. 1 Clearance Warning Buzzer Circuit
DESCRIPTION
The clearance warning ECU receives the ultrasonic sensor signal to sound the front warning buzzer.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT FRONT BUZZER
- Remove the clearance warning ECU with front buzzer.
- Apply the battery voltage to the terminals 1 and 2 of the buzzer, and check that the buzzer sounds.
HINT: The clearance warning buzzer is separately excited, and will not sound unless an alternating voltage is applied.
OK: Operating noise (clicking sounds) can be heard.
2 CHECK HARNESS AND CONNECTOR (CLEARANCE WARNING ECU - FRONT BUZZER)
- Disconnect the clearance warning ECU connector and front buzzer connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
Rear Clearance Sonar Sensor RH Circuit
DESCRIPTION
An ultrasonic sensor consists of a sensor portion that transmits and receives
ultrasonic waves and a preamplifier
that amplifies them. The ultrasonic sensor outputs the ultrasonic wave ...
Clearance Warning ECU Power Source Circuit
DESCRIPTION
This circuit provides power to the clearance warning ECU.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 CHECK HARNESS AND CONNECTOR (CLEARANCE WARNING ECU - AIR CONDITIONER
AMPLIFIER)
...
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DESCRIPTION
The ECM calculates the difference between the readings of the coolant
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and will set this DTC.
HINT:
Waiting is required t ...
Fuel Pump Control Circuit
DESCRIPTION
The FUEL PUMP relay switches the fuel pump speed according to the engine
conditions. The fuel pump
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Front Occupant Classification Sensor RH Collision
Detection
DTC B1786 Front Occupant Classification Sensor RH Collision
Detection
DESCRIPTION
DTC B1786 is output when the occupant classification ECU receives a collision
detection signal sent by
the front occupant classification sensor RH if an accident occurs.
DTC B1786 is also output when the front ...