B1413

AIR CONDITIONING SYSTEM: B1413/13: Evaporator Temperature Sensor Circuit

DTC B1413/13 - Evaporator Temperature Sensor Circuit

DESCRIPTION

The A/C evaporator temperature sensor is installed on the evaporator in the air conditioner unit to detect the cooled air temperature that has passed through the evaporator and control the air conditioning. It sends appropriate signals to the A/C amplifier assembly. The resistance of the A/C evaporator temperature sensor changes in accordance with the cooled air temperature that has passed through the evaporator. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.
The A/C amplifier assembly applies voltage (5 V) to the A/C evaporator temperature sensor and reads voltage changes as the resistance of the A/C evaporator temperature sensor changes. This sensor is used for frost prevention.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING INTELLIGENT TESTER
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch ON 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.
Result:






C -- REPLACE AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.
2. INSPECT AIR CONDITIONING AMPLIFIER





(a) Remove the A/C amplifier with the connectors still connected.
(b) Measure the voltage according to the table value(s) in the table below.
Standard voltage:





HINT: As the temperature increases, the voltage decreases.

Result:






C -- REPLACE AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.
3. INSPECT A/C EVAPORATOR TEMPERATURE SENSOR





(a) Remove the A/C evaporator temperature sensor (A/C thermistor).
(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 evaporator temperature.
HINT: As the temperature increases, the resistance decreases (see the graph).

NG -- REPLACE A/C EVAPORATOR TEMPERATURE SENSOR
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (A/C EVAPORATOR TEMPERATURE SENSOR - A/C AMPLIFIER)





(a) Disconnect the connector from the A/C amplifier.





(b) Disconnect the connector from the A/C evaporator temperature sensor.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE AIR CONDITIONING AMPLIFIER