Toyota Sienna Service Manual: Room Temperature Sensor Circuit
DESCRIPTION
This sensor detects the 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 ignition switch to the ON position and turn the intelligent tester main switch on.
(c) Select the item below in the DATA LIST, and read the display on the intelligent tester.
DATA LIST / AIR CONDITIONER: 
OK: The display is as specified in the normal condition column.
Result 
2 INSPECT A/C ROOM TEMPERATURE SENSOR
(a) Remove the A/C room temperature sensor.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance 
NOTICE:
- Hold the sensor only by its connector. Touching the sensor may change the resistance value.
- When measuring, the sensor temperature must be the same as the room temperature.
HINT: As the temperature increases, the resistance decreases (see the graph).
3 CHECK HARNESS AND CONNECTOR (A/C ROOM TEMPERATURE SENSOR - A/C AMPLIFIER)
(a) Disconnect the connector from the A/C amplifier.
(b) Disconnect the connector from the A/C room temperature sensor.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance 
REPLACE A/C AMPLIFIER
Actuator check
1. ACTUATOR CHECK
(a) After entering the DTC check mode (Sensor Check
Mode), press the R/F switch.
(b) As each damper, motor and relay automatically
operate actuator check at 1-second interval ...
Ambient temperature sensor circuit
DTC B1412/12 Ambient Temperature Sensor Circuit
DESCRIPTION
The ambient temperature sensor is installed in front of the condenser to
detect the ambient temperature
which is used to control the ai ...
Other materials:
Removal
1. DRAIN BRAKE FLUID
NOTICE:
Wash brake fluid off immediately if it adheres to any
painted surface.
2. DISCONNECT BATTERY NEGATIVE TERMINAL
3. REMOVE AIR CLEANER ASSEMBLY WITH HOSE
4. REMOVE BRAKE ACTUATOR WITH BRACKET
(a) Release the latch of the brake actuator connector to
disconnect t ...
How to proceed with
troubleshooting
HINT:
Use these procedures to troubleshoot the key reminder
warning system.
The intelligent tester should be used in steps 3 and 5.
1 VEHICLE BROUGHT TO WORKSHOP
2 CUSTOMER PROBLEM ANALYSIS
3 INSPECT COMMUNICATION FUNCTION OF MULTIPLEX COMMUNICATION SYSTEM
(BEAN)
Use th ...
Input instructions
(a) The general VIN input instructions using the
intelligent tester are shown below:
(b) The arrow buttons (UP, DOWN, RIGHT and LEFT)
and numerical buttons (0 to 9) are used to input the
VIN.
(c) Cursor Operation
To move the cursor around the tester screen, press
the RIGHT and LEFT buttons. ...
