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).
- Check wire harness (no. 1 Cooler thermistor - air conditioning amplifier)
- Disconnect the e33 no. 1 Cooler thermistor connector.
- Disconnect the e36 amplifier connector.
- Measure the resistance of the wire harness side connectors.
Standard resistance 
Replace air conditioning amplifier
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 ...
Compressor lock sensor circuit
Description
This sensor sends 1 pulse per engine revolution to the air conditioning
amplifier. If the ratio of the
compressor speed divided by the engine speed is smaller than a predetermined ...
Other materials:
Throttle actuator control motor current range / performance
Description
The etcs (electronic throttle control system) has a dedicated power supply
circuit. The voltage (+bm)
is monitored and when it is low (less than 4 v), the ecm determines that there
is a malfunction in the
etcs and cuts off the current to the throttle actuator.
When the volt ...
Air inlet damper control servo motor circuit
Description
The damper servo (air inlet control) sends pulse signals to indicate the
damper position to the air
conditioning amplifier. The air conditioning amplifier activates the motor
(normal or reverse) based on
these signals to move the air inlet control damper to the appropriate pos ...
Diagnosis system
Description
Data of the system can be read through the data
link connector 3 (dlc3) of the vehicle.
Therefore, when the system seems to be
malfunctioning, use the intelligent tester to check for
a malfunction and repair it.
Check dlc3
The vehicle's ecm uses iso 157 ...
