Toyota Sienna Service Manual: Rear evaporator temperature sensor circuit

DESCRIPTION

The rear evaporator temperature sensor is installed on the rear evaporator. It detects the rear evaporator temperature. The sensor sends a signal to the A/C amplifier. The resistance of the rear evaporator temperature sensor changes in accordance with the rear evaporator temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The A/C amplifier applies voltage (5 V) to the rear evaporator temperature sensor and reads voltage changes as the resistance of the rear evaporator temperature sensor changes.

WIRING DIAGRAM

INSPECTION PROCEDURE

1 READ VALUE OF INTELLIGENT TESTER

(a) Connect the intelligent tester to the DLC3.

(b) Turn the ignition switch to the ON position and turn the intelligent tester main switch on.

(c) Select the item below in the DATA LIST, and read the display on the intelligent tester.

DATA LIST / AIR CONDITIONER:

OK: The display is as specified in the normal condition column.

Result

2 INSPECT REAR EVAPORATOR TEMPERATURE SENSOR

(a) Remove the rear evaporator temperature sensor.

(b) Measure the resistance according to the value(s) in the table below.

Standard resistance

NOTICE:

• Even slightly touching the sensor 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 rear evaporator temperature.

HINT: As the temperature increases, the resistance decreases (see the graph).

3 CHECK HARNESS AND CONNECTOR (REAR EVAPORATOR TEMPERATURE SENSOR - A/C AMPLIFIER)

(a) Disconnect the rear evaporator temperature sensor connector.

(b) Disconnect the A/C amplifier connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard resistance

REPLACE A/C AMPLIFIER