Toyota Sienna Service Manual: IG Power Source Circuit
DESCRIPTION
The main power source is supplied to the A/C amplifier when the ignition switch is turned to the ON position.
The power source is used for operating the A/C amplifier and servo motor, etc.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT: Start the engine before inspection. Check the IG1 relay or battery if the engine does not start.
1 INSPECT FUSE (HTR)
(a) Remove the HTR fuse from the driver side junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance 
2 INSPECT A/C AMPLIFIER (IG - GND)
(a) Remove the A/C amplifier with its connectors still connected.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage 
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
3 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
4 CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BODY GROUND)
(a) Measure the resistance according to the value(s) in the table below.
Standard resistance 
REPLACE A/C AMPLIFIER
Rear Blower Motor Circuit
DESCRIPTION
Power to the rear blower motor is supplied from the battery via the RR A/C
relay.
The rear blower motor speed level varies between 0 and 31 based on the voltage
difference measured ...
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 ...
Other materials:
Engine
GENERAL MAINTENANCE
HINT:
Inspect these items when the engine is cold.
1. INSPECT DRIVE BELT
HINT:
(See page EM-6)
2. REPLACE SPARK PLUGS
HINT:
(See page IG-8)
3. INSPECT AIR FILTER
(a) Remove the air filter.
(b) Visually check that the air filter is not excessively
damaged or oily ...
Throttle Actuator Control Motor Circuit
DTC P2102 Throttle Actuator Control Motor Circuit Low
DTC P2103 Throttle Actuator Control Motor Circuit High
DESCRIPTION
The throttle actuator is operated by the ECM and opens and closes the
throttle valve using gears.
The opening angle of the throttle valve is detected by the Throttle Posit ...
Removal
1. REMOVE BATTERY (See page EM-26)
2. REMOVE NO. 2 AIR CLEANER INLET (See page EM-
28)
3. REMOVE AIR CLEANER CAP SUB-ASSEMBLY (See
page FU-13)
4. REMOVE AIR CLEANER FILTER ELEMENT (See page
EM-28)
5. REMOVE AIR CLEANER CASE SUB-ASSEMBLY (See
page EM-28)
6. REMOVE AIR CLEANER BRACKET
(a ...
