DTC    B1413/13    Evaporator Temperature Sensor Circuit

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DESCRIPTION

The A/C evaporator temperature sensor (A/C thermistor) 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 (A/C thermistor) 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 (A/C thermistor) and reads voltage changes as the resistance of the A/C evaporator temperature sensor (A/C thermistor) changes. This sensor is used for frost prevention.

DTC No.
DTC Detecting Condition
Trouble Area
B1413/13
Open or short in evaporator temperature sensor circuit
  1. A/C evaporator temperature sensor (A/C thermistor)
  2. Harness or connector between A/C evaporator temperature sensor and A/C amplifier assembly
  3. A/C amplifier assembly

WIRING DIAGRAM


I036318E04


INSPECTION PROCEDURE

1.READ VALUE OF INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and push the intelligent tester main switch on.

  1. Select the item below in the DATA LIST, and read the display on the intelligent tester.


DATA LIST / AIR CONDITIONER 
Item
Measurement Item/Display
(Range)
Normal Condition
Diagnostic Note
EVAP TEMP
Evaporator temperature sensor / min.: -29.7°C (-21.46°F) max.: 59.55°C (139.19°F)
Actual evaporator temperature is displayed
Open in the circuit: -29.7°C (-21.46°F)
Short in the circuit: 59.55°C (139.19°F)

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


Result:

Result
Proceed to
NG
A
OK (Checking from the PROBLEM SYMPTOMS TABLE)
B
OK (Checking from the DTC)
C



B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
A


2.INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY


    E109265E25

  1. Remove the A/C amplifier assembly with the connectors still connected.

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

    Voltage:
    Tester connection
    (Symbols)
    		Condition
    		Specified condition
    A10-12 (TE) - A10-11 (SG)
    		Ignition switch ON
    at 0°C (32°F)
    		2.2 to 2.6 V
    A10-12 (TE) - A10-11 (SG)
    		Ignition switch ON
    at 15°C (59°F)
    		1.3 to 1.7 V

    HINT:
    As the temperature increases, the voltage decreases.


Result:

Result
Proceed to
NG
A
OK (Checking from the PROBLEM SYMPTOMS TABLE)
B
OK (Checking from DTC)
C



B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
A


3.INSPECT A/C EVAPORATOR TEMPERATURE SENSOR


    E112577E03

  1. Remove the A/C evaporator temperature sensor (A/C thermistor).

  1. Disconnect the connector from the A/C evaporator temperature sensor (A/C thermistor).



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


    I036421E01

    Resistance:
    Tester connection
    		Condition
    		Specified condition
    A14-1 - A14-2
    		-10°C (14°F)
    		7.30 to 9.10 kΩ
    A14-1 - A14-2
    		-5°C (23°F)
    		5.65 to 6.95 kΩ
    A14-1 - A14-2
    		0°C (32°F)
    		4.40 to 5.35 kΩ
    A14-1 - A14-2
    		5°C (41°F)
    		3.40 to 4.15 kΩ
    A14-1 - A14-2
    		10°C (50°F)
    		2.70 to 3.25 kΩ
    A14-1 - A14-2
    		15°C (59°F)
    		2.14 to 2.58 kΩ
    A14-1 - A14-2
    		20°C (68°F)
    		1.71 to 2.05 kΩ
    A14-1 - A14-2
    		25°C (77°F)
    		1.38 to 1.64 kΩ
    A14-1 - A14-2
    		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).



NG
REPLACE A/C EVAPORATOR TEMPERATURE SENSOR
OK


4.CHECK HARNESS AND CONNECTOR (A/C EVAPORATOR TEMPERATURE SENSOR - A/C AMPLIFIER ASSEMBLY)


    E108940E03

  1. Disconnect the connector from the A/C amplifier assembly.

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

    Resistance:
    Tester connection
    (Symbols)
    		Condition
    		Specified condition
    A10-12 (TE) - A14-2
    		Always
    		Below 1 Ω
    A10-11 (SG) - A14-1
    		Always
    		Below 1 Ω
    A10-12 (TE) - Body ground
    		Always
    		10 kΩ or higher
    A10-11 (SG) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY