Toyota Tacoma 2015-2018 Service Manual: Evaporator Temperature Sensor Circuit (B1413)

Toyota Tacoma 2015-2018 Service Manual / Air Conditioning / Air Conditioning System(for Manual Air Conditioning System) / Evaporator Temperature Sensor Circuit (B1413)

DESCRIPTION

The cooler thermistor sensor (evaporator temperature sensor) 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 is used to control the air conditioning. It sends signals to the air conditioning amplifier assembly. The resistance of the cooler thermistor sensor (evaporator temperature sensor) changes in accordance with the temperature of the cooled air that has passed through the evaporator. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

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

DTC No.	DTC Detection Condition	Trouble Area
B1413	Open or short in cooler thermistor sensor (evaporator temperature sensor) circuit	Cooler thermistor sensor (Evaporator temperature sensor) Harness or connector Air conditioning amplifier assembly

WIRING DIAGRAM

PROCEDURE

1.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(d) Enter the following menus: Body Electrical / Air Conditioner / Data List.

(e) Check the value(s) by referring to the table below.

Air Conditioner

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Evaporator Fin Thermistor	Cooler thermistor sensor (Evaporator temperature sensor) / Min.: -29.70°C (-21.46°F) Max.: 59.55°C (139.19°F)	Actual evaporator temperature displayed	-

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Evaporator Fin Thermistor

Cooler thermistor sensor (Evaporator temperature sensor) /

Min.: -29.70°C (-21.46°F)

Max.: 59.55°C (139.19°F)

Actual evaporator temperature displayed

OK:

The display is as specified in the Normal Condition column.

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

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

2.	INSPECT COOLER THERMISTOR SENSOR (EVAPORATOR TEMPERATURE SENSOR)

(a) Remove the cooler thermistor sensor (evaporator temperature sensor) (See page (b) Inspect the cooler thermistor sensor (evaporator temperature sensor) (See ).

(b) Inspect the cooler thermistor sensor (evaporator temperature sensor) (See page ).

REPLACE COOLER THERMISTOR SENSOR (EVAPORATOR TEMPERATURE SENSOR)

3.	CHECK HARNESS AND CONNECTOR (COOLER THERMISTOR SENSOR (EVAPORATOR TEMPERATURE SENSOR) - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the A17 cooler thermistor sensor (evaporator temperature sensor) connector.

(b) Disconnect the A14 air conditioning amplifier assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A14-6 (TE) - A17-2	Always	Below 1 Ω
A14-32 (SG-2) - A17-1	Always	Below 1 Ω
A14-6 (TE) or A17-2 - Body ground	Always	10 kΩ or higher
A14-32 (SG-2) or A17-1 - Body ground	Always	10 kΩ or higher

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

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