Toyota RAV4 (XA40) 2013-2018 Service Manual: 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 combination meter and detects fluctuations in the ambient temperature. This data is used for controlling the room temperature.
The sensor sends a signal to the air conditioning amplifier via the combination meter. The resistance of the ambient temperature sensor changes in accordance with the ambient 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 ambient temperature sensor and reads voltage changes as changes in the resistance of the ambient temperature sensor. The combination meter sends the read signal to the air conditioning amplifier via can communication.
Wiring diagram
Inspection procedure
- Read value of intelligent tester (ambi temp sens)
- 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 ambient temperature sensor
- Remove the ambient 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 (ambient temperature sensor - combination meter)
- Disconnect the a17 sensor connector.
- Disconnect the e19 meter connector.
- Measure the resistance of the wire harness side connectors.
Standard resistance 
Replace combination meter
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Description
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the room temperature and
control the heater and air conditioner auto mode. The resistance of the room
t ...
Evaporator temperature sensor circuit
Description
The no. 1 Cooler thermistor (evaporator temperature sensor) is installed on
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Other materials:
Vehicle information display
â– Drive information
2 items that are selected using
the "Drive Info Items" setting
(average speed, distance and total time) can be displayed vertically.
The displayed information
changes according to the "Drive
Info Type" setting (since the system
was started or between
resets).
Use the displayed ...
Air conditioning control panel does not operate
Description
This circuit consists of the air conditioning control and the air
conditioning amplifier. When the air
conditioning control is operated, signals are transmitted to the air
conditioning amplifier through the lin
communication system.
If the lin communication system malfunctions, ...
Abs warning light remains on
Description
If any of the following conditions are detected, the abs warning light
remains on:
The ecu connectors are disconnected from the skid control ecu.
There is a malfunction in the skid control ecu internal circuit.
There is an open or short in the wire harness between the combinat ...
