B1413

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

DTC B1413 - Evaporator Temperature Sensor Circuit

DESCRIPTION

The 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 air conditioning amplifier. The resistance of the 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 air conditioning amplifier applies voltage (5 V) to the evaporator temperature sensor and reads voltage changes as the resistance of the evaporator temperature sensor changes. This sensor is used for frost prevention.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM
(a) Connect Techstream to DLC3.
(b) Turn the power switch ON (IG) and turn Techstream ON.
(c) Select the item below in the Data List, and read the display on Techstream.

Air conditioning amplifier





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. CHECK AIR CONDITIONING AMPLIFIER (TE VOLTAGE)




(a) Remove the air conditioning amplifier with connectors still connected.
(b) Measure the voltage of the wire harness side connector.
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 EVAPORATOR TEMPERATURE SENSOR




(a) Remove the evaporator temperature sensor.
(b) Measure the resistance of the sensor.
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 ambient temperature.
HINT: As the temperature increases, the resistance decrease (see the graph).

NG -- REPLACE EVAPORATOR TEMPERATURE SENSOR
OK -- Continue to next step.

4. CHECK WIRE HARNESS (EVAPORATOR TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER)




(a) Disconnect the A11 sensor connector.
(b) Disconnect the A7 amplifier connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






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