Toyota Tundra Service Manual: Room Temperature Sensor Circuit (B1411/11)

Toyota Tundra Service Manual / Vehicle Interior / Air Conditioning / Air Conditioning System(for Automatic Air Conditioning System) / Room Temperature Sensor Circuit (B1411/11)

DESCRIPTION

The room temperature sensor is installed in the instrument panel to detect the room temperature and control the heater and air conditioner "AUTO" mode. The resistance of the room temperature sensor changes in accordance with the room temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning amplifier applies voltage (5 V) to the room temperature sensor and reads voltage changes as the resistance of the room temperature sensor changes. This sensor also sends the appropriate signals to the air conditioning amplifier.

DTC Code	DTC Detection Condition	Trouble Area
B1411/11	Open or short in room temperature sensor circuit	Room temperature sensor Harness or connector between room temperature sensor and air conditioning amplifier Air conditioning amplifier

WIRING DIAGRAM

PROCEDURE

1.	READ VALUE USING TECHSTREAM (ROOM TEMPERATURE SENSOR)

(a) Use the Data List to check if the room temperature sensor is functioning properly.

Air Conditioner

Tester Display

Measurement Item / Range

Normal Condition

Diagnostic Note

Room Temperature Sensor

Room temperature sensor /

Min.: -6.5°C (20.3°F)

Max.: 57.25°C (135.05°F)

Actual room temperature is displayed

Open in circuit: -6.5°C (20.3°F)

Short in circuit: 57.25°C (135.05°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

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

REPLACE AIR CONDITIONING AMPLIFIER

2.	INSPECT ROOM TEMPERATURE SENSOR

(a) Remove the room temperature sensor (see page ).

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

Standard resistance:

Tester Connection	Condition	Specified Condition
1 - 2	10°C (50°F)	3.00 to 3.73 kΩ
	15°C (59°F)	2.45 to 2.88 kΩ
	20°C (68°F)	1.95 to 2.30 kΩ
	25°C (77°F)	1.60 to 1.80 kΩ
	30°C (86°F)	1.28 to 1.47 kΩ
	35°C (95°F)	1.00 to 1.22 kΩ
	40°C (104°F)	0.80 to 1.00 kΩ
	45°C (113°F)	0.65 to 0.85 kΩ
	50°C (122°F)	0.50 to 0.70 kΩ
	55°C (131°F)	0.44 to 0.60 kΩ
	60°C (140°F)	0.36 to 0.50 kΩ

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 decreases (see the graph).

REPLACE ROOM TEMPERATURE SENSOR

3.	CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER)

(a) Disconnect the J16 sensor connector.

(b) Disconnect the J19 air conditioning amplifier connector.

Standard resistance:

Tester Connection	Condition	Specified Condition
J16-1 - J19-29 (TR)	Always	Below 1 Ω
J16-2 - J19-34 (SG-1)	Always	Below 1 Ω
J16-1 or J19-29 (TR) - Body ground	Always	10 kΩ or higher
J16-2 or J19-34 (SG-1) - Body ground	Always	10 kΩ or higher

REPLACE AIR CONDITIONING AMPLIFIER

REPAIR OR REPLACE HARNESS OR CONNECTOR

Air Conditioning Compressor Magnetic Clutch Circuit

Ambient Temperature Sensor Circuit (B1412/12)

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