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
B

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C

REPLACE AIR CONDITIONING AMPLIFIER

A

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).

NG

REPLACE ROOM TEMPERATURE SENSOR

OK

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.

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

Standard resistance:

Tester Connection

Condition

Specified Condition

J16-1 - J19-29 (TR)

Always

Below 1 Ω

J16-2 - J19-34 (SG-1)

J16-1 or J19-29 (TR) - Body ground

Always

10 kΩ or higher

J16-2 or J19-34 (SG-1) - Body ground
OK

REPLACE AIR CONDITIONING AMPLIFIER

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
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