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:
Check mode procedure
Hint:
Intelligent tester only:
compared to normal mode, check mode is more sensitive to
malfunctions. Therefore, check mode can detect the
malfunctions that cannot be detected by normal mode.
Notice:
All the stored dtcs and freeze frame data are erased if:
The ecm is changed from normal mo ...
For vehicles equipped with catalytic converter caution:
If a large amount of unburned gasoline or gasoline
vapors flow into the converter, it may cause
overheating and create a fire hazard. To prevent this,
observe the following precautions.
Use only unleaded gasoline.
Avoid idling the engine for more than 20 minutes.
Avoid performing unnecess ...
Multiplex communication circuit
Description
The air conditioning amplifier communicates data with the ecm and combination
meter through the can
communication system.
Wiring diagram
Inspection procedure
Check dtc
Clear the dtc (see page ac-127).
Read the dtc (see page ac-127).
Result
Go to can ...
