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:
How to proceed with troubleshooting
Hint:
Use these procedures to troubleshoot the lighting system.
*: Use the intelligent tester.
Vehicle brought to workshop
Inspect battery voltage
Standard voltage:
11 to 14 v
If the voltage is below 11 v, recharge or replace the battery
before proceeding.
Refer to pr ...
Emission inspection
and maintenance (i/m)
programs
Some states have vehicle emission inspection programs which
include obd (on board diagnostics) checks. The obd system
monitors the operation of the emission control system.
If the malfunction indicator lamp comes on
The obd system determines that a problem exists somewhere in the
emission contr ...
Hazard warning switch
Components
Removal
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.
Remove no. 1 Instrument cluster finish
panel cente ...
