DTC    B1413    Evaporator Temperature Sensor Circuit

for Preparation Click here


DESCRIPTION

The front evaporator temperature sensor (No. 1 cooler thermistor) is installed on the evaporator in the air conditioner 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, which changes in accordance with the resistance of the front evaporator temperature sensor (No. 1 cooler thermistor). As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.
The air conditioning amplifier applies voltage (5 V) to the front evaporator temperature sensor (No. 1 cooler thermistor) and reads voltage changes as the resistance of the front evaporator temperature sensor (No. 1 cooler thermistor) changes. This sensor is used for frost prevention.

DTC No.
DTC Detection Condition
Trouble Area
B1413
Open or short in evaporator temperature sensor circuit
  1. Front evaporator temperature sensor (No. 1 cooler thermistor)
  2. Harness and connector between front evaporator temperature sensor (No. 1 cooler thermistor) and air conditioning amplifier
  3. Air conditioning amplifier

WIRING DIAGRAM


E177088E01


INSPECTION PROCEDURE

1.READ VALUE USING INTELLIGENT TESTER (EVAPORATOR FIN THERMISTOR)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

  1. Enter the following menus: Body / Air Conditioner / Data List.

  1. According to the display on the intelligent tester, read the Data List.

    Air Conditioner 
    Tester Display
    		Measurement Item/Display (Range)
    		Normal Condition
    		Diagnostic Note
    Evaporator Fin Thermistor
    		Evaporator fin thermistor / Min.: -29.7°C (-21.46°F), Max.: 59.55°C (139.19°F)
    		Actual evaporator temperature is displayed
    		Open in circuit: -29.7°C (-21.46°F)
    Short in circuit: 59.55°C (139.019°F)

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


Result 
Result
Proceed to
NG
A
OK (When troubleshooting according to Problem Symptoms Table)
B
OK (When troubleshooting according to the DTC output)
C


B
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (Click here)

C
REPLACE AIR CONDITIONING AMPLIFIER (Click here)
A


2.INSPECT FRONT EVAPORATOR TEMPERATURE SENSOR (NO. 1 COOLER THERMISTOR)


    E177531E01

  1. Remove the front evaporator temperature sensor (No. 1 cooler thermistor).

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 - 2
    		-10°C (14°F)
    		7.30 to 9.10 kΩ
    -5°C (23°F)
    		5.65 to 6.95 kΩ
    0°C (32°F)
    		4.40 to 5.35 kΩ
    5°C (41°F)
    		3.40 to 4.15 kΩ
    10°C (50°F)
    		2.70 to 3.25 kΩ
    15°C (59°F)
    		2.14 to 2.58 kΩ
    20°C (68°F)
    		1.71 to 2.05 kΩ
    25°C (77°F)
    		1.38 to 1.64 kΩ
    30°C (86°F)
    		1.11 to 1.32 kΩ

    NOTICE:
    1. Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.
    2. When measuring, the sensor temperature must be the same as the ambient temperature.

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

  1. Reinstall the front evaporator temperature sensor (No. 1 cooler thermistor).



NG
REPLACE FRONT EVAPORATOR TEMPERATURE SENSOR (NO. 1 COOLER THERMISTOR) (Click here)
OK


3.CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - NO. 1 COOLER THERMISTOR)


    E176776E01

  1. Disconnect the D10 front evaporator temperature sensor (No. 1 cooler thermistor) connector.

  1. Disconnect the D16 air conditioning amplifier connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    D16-22 (TE) - D10-2
    		Always
    		Below 1 Ω
    D16-10 (SG-2) - D10-1
    		Always
    		Below 1 Ω
    D16-22 (TE) - Body ground
    		Always
    		10 kΩ or higher
    D16-10 (SG-2) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the air conditioning amplifier connector.

  1. Reconnect the front evaporator temperature sensor (No. 1 cooler thermistor) connector.

Text in Illustration 
*1
Front view of wire harness connector
(to Front Evaporator Temperature Sensor (No. 1 Cooler Thermistor))
*2
Front view of wire harness connector
(to Air Conditioning Amplifier)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER (Click here)