Toyota Sienna Service Manual: Back-up Power Source Circuit
DESCRIPTION
This is the back-up power source for the A/C amplifier. Power is supplied even when the ignition switch is off and is used for diagnostic trouble code memory, etc.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT FUSE (ECU-B)
(a) Remove the ECU-B fuse from the engine room junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance
2 CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY)
(a) Disconnect the connector from the A/C amplifier.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
ACC Power Source Circuit
DESCRIPTION
This circuit supplies power to the A/C amplifier and the illumination for the
clock.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT FUSE (ECU ACC)
(a) Remove the ECU ACC fuse fr ...
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Rear Room Temperature Sensor Circuit
DESCRIPTION
This sensor detects the rear cabin temperature that is used as the basis for
temperature control and
sends a signal to the A/C amplifier.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 READ VALUE OF INTELLIGENT TESTER
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ign ...
Reverse Signal Circuit
DESCRIPTION
The radio and navigation assembly receives a reverse signal from the
park/neutral position switch.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT RADIO AND NAVIGATION ASSEMBLY
Disconnect the radio and navigation assembly connector
R12.
Measure the voltage accor ...
Check for open circuit
(a) For an open circuit in the wire harness in Fig. 1, the resistance or
voltage, as described below.
(b) Check the resistance.
Check the resistance
Standard resistance (Fig. 2)
HINT:
Measure the resistance while lightly shaking the
wire harness vertically and horizontally. I ...
