Toyota RAV4 (XA40) 2013-2018 Service Manual: Room temperature sensor circuit
Description
The room temperature sensor is installed in the instrument panel to detect the room temperature and control the heater and air conditioner auto mode. The resistance of the room temperature sensor changes in accordance with the room temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.
The air conditioning amplifier applies a voltage (5 v) to the room temperature sensor and reads voltage changes as changes in the resistance of the room temperature sensor.
Wiring diagram
Inspection procedure
- Read value of intelligent tester (room temp)
- Connect the intelligent tester (with can vim) to the dlc3.
- Turn the ignition switch on and turn the intelligent tester main switch on.
- Select the item below in the data list, and read the value displayed on the intelligent tester.
Ok: the display is as specified in the normal condition column.
- Inspect cooler thermistor (room temperature sensor)
- Remove the room temperature sensor.
- Measure the resistance of the sensor.
Standard resistance 
Notice:
- Touching the sensor even slightly may change the resistance value. Be sure to hold the connector of the sensor.
- When measuring, the sensor temperature must be the same as the ambient temperature.
Hint:
As the temperature increases, the resistance decreases (see the graph).
- Check wire harness (room temperature sensor - air conditioning amplifier)
- Disconnect the e21 sensor connector.
- Disconnect the e37 amplifier connector.
- Measure the resistance of the wire harness side connectors.
Standard resistance 
Replace air conditioning amplifier assembly
Diagnostic trouble code chart (2006/01- )
Hint:
When the air conditioning system functions properly, dtc
b1400/00 is output.
Hint:
*1: Dtc b1422/22 (compressor lock sensor circuit) is
indicated only for a currently occurring malf ...
Ambient temperature sensor circuit
Description
The ambient temperature sensor is installed in the front part of the
condenser to detect the ambient
temperature and control the air conditioner. The sensor is connected to the
c ...
Other materials:
Integration relay
On-vehicle inspection
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensioner activation.
Inspect integration relay
Notice:
The efi relay ...
Basic inspection
When measuring resistance of
electronic parts
Unless otherwise stated, all resistance
measurements should be made at an ambient
temperature of 20°c (68°f). Resistance
measurements may be inaccurate if measured
at high temperatures, i.E. Immediately after the
vehicle has been r ...
Precaution
If any of following conditions are met,
keep engine idling with a/c on (engine
speed at less than 2000 rpm) for at least 1
minute:
Refrigerant gas has been refilled or a/c parts have
been replaced.
A long time has elapsed since the engine was
stopped.
Notice:
If the engine s ...
