Toyota RAV4 (XA40) 2013-2018 Service Manual: Evaporator temperature sensor circuit
Description
The no. 1 Cooler thermistor (evaporator temperature sensor) is installed on the evaporator in the air conditioning unit to detect the temperature of the cooled air that has passed through the evaporator and to control the air conditioner. It sends signals to the air conditioning amplifier. The signals change in accordance with the resistance of the no. 1 Cooler thermistor (evaporator temperature sensor). 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 no. 1 Cooler thermistor (evaporator temperature sensor) and reads voltage changes as changes in the resistance of the no. 1 Cooler thermistor (evaporator temperature sensor). This sensor is used for frost prevention.
Wiring diagram
Inspection procedure
- Read value of intelligent tester (evap fin 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 no. 1 Cooler thermistor (evaporator temperature sensor)
- Remove the no. 1 Cooler thermistor.
- Measure the resistance of the thermistor.
Standard resistance 
Notice:
- Touching the thermistor even slightly may change the resistance value. Be sure to hold the connector of the thermistor.
- When measuring, the thermistor temperature must be the same as the ambient temperature.
Hint:
As the temperature increases, the resistance decreases (see the graph).
Replace air conditioning harness assembly
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 ...
Solar sensor circuit (passenger side)
Description
The solar sensor, which is installed on the upper side of the instrument
panel, detects sunlight and
controls the air conditioning auto mode. The output voltage from the solar
se ...
Other materials:
Diagnosis system
Description
Air conditioning system data and the diagnostic
trouble codes (dtcs) can be read through the
data link connector 3 (dlc3) of the vehicle. When
the system seems to be malfunctioning, use the
intelligent tester to check for malfunctions and
perform troubleshooting.
...
Downhill assist control indicator light remains on
Description
When the downhill assist control switch is pushed on, the downhill assist
control function is available and
the downhill assist control indicator light illuminates.
Hint:
Even if the downhill assist control switch is pressed, the downhill assist
control indicator light will blink ...
On-vehicle inspection
Check battery condition
Notice:
If the battery is weak or if the engine is difficult to
start, perform the following procedures.
Check the battery for damage and deformation. If
severe damage, deformation or leakage is found,
replace the battery.
Check the electrolyte quantity of e ...
