Toyota Sienna Service Manual: No. 2 Clearance Warning Buzzer Circuit

DESCRIPTION

The clearance warning ECU receives the ultrasonic sensor signal to sound the rear warning buzzer.

WIRING DIAGRAM

INSPECTION PROCEDURE

1 CHECK HARNESS AND CONNECTOR (CLEARANCE WARNING ECU - AIR CONDITIONER AMPLIFIER)

1. Disconnect the connectors from the clearance warning ECU C9 and air conditioner amplifier connector A10 or A11.
2.  Measure the resistance according to the value(s) in the table below.

Standard resistance

2 INSPECT REAR BUZZER

1. Remove the integration control & panel assembly with the connectors still connected.
2.  Using a service wire, ground the terminal Z- of the integration control & panel assembly connector.
3.  Turn the ignition switch ON.
4.  Check that the rear 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.

Result

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

3 INSPECT PRINTED WIRE INTEGRATION BOARD SUB-ASSEMBLY

1. Check that the malfunction disappears when a known good printed wire integration board sub-assembly is installed.

OK: Malfunction disappears.

REPLACE PRINTED WIRE INTEGRATION BOARD SUB-ASSEMBLY

4 INSPECT INTEGRATION PANEL SUB-ASSEMBLY

1. Check that the malfunction disappears when a known good integration panel sub-assembly is installed.

OK: Malfunction disappears

REPLACE INTEGRATION PANEL SUB-ASSEMBLY