Toyota Tundra. Manual — part 2396

HINT:

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

NG: REPLACE ROOM TEMPERATURE SENSOR (See REMOVAL )

OK: Go to Next Step

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.

45°C (113°F) 0.65 to 0.85 kohms
50°C (122°F) 0.50 to 0.70 kohms
55°C (131°F) 0.44 to 0.60 kohms
60°C (140°F) 0.36 to 0.50 kohms

NOTE:



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.

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra

Fig. 31: Identifying Terminals Of J16 Room Temperature Sensor And J19 Air Conditioning
Amplifier Connectors
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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

Standard Resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE AIR CONDITIONING AMPLIFIER (See REMOVAL )

DTC B1412/12 AMBIENT TEMPERATURE SENSOR CIRCUIT

DESCRIPTION

Tester Connection

Condition Specified Condition

J16-1 - J19-29 (TR)

Always

Below 1 ohms

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

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

Always

10 kohms or higher

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

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra

The ambient temperature sensor is installed in front of the condenser to detect the ambient temperature which is
used to control the air conditioner "AUTO" mode. This sensor is connected to the air conditioning amplifier and
detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The
sensor sends a signal to the air conditioning amplifier. The resistance of the ambient temperature sensor changes
in accordance with the ambient 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 ambient temperature sensor and reads voltage
changes as the resistance of the ambient temperature sensor changes.

DTC DETECTION CONDITION CHART

WIRING DIAGRAM

Fig. 32: Ambient Temperature Sensor - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

1. READ VALUE USING TECHSTREAM (AMBIENT TEMPERATURE SENSOR)

a. Use the Data List to check if the ambient temperature sensor is functioning properly.

Air Conditioner

DATA LIST

DTC

DTC Detection Condition

Trouble Area

B1412/12

Open or short in ambient
temperature sensor circuit



Ambient temperature sensor



Harness or connector
between ambient temperature
sensor and air conditioning
amplifier



Air conditioning amplifier

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra

OK:

The display is as specified in the normal condition.

Result

RESULT REFERENCE

B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE (See PROBLEM SYMPTOMS TABLE )

C: REPLACE AIR CONDITIONING AMPLIFIER (See REMOVAL )

A: Go to Next Step

2. INSPECT AMBIENT TEMPERATURE SENSOR

a. Remove the ambient temperature sensor (see REMOVAL ).

Tester

Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Ambient Temp

Sensor

Ambient temperature
sensor/Min.: -23.3°C (-9.94°F)
Max.: 65.95°C (150.71°F)

Actual ambient
temperature is displayed

Open in circuit: -23.3°
C (-9.94°F)
Short in circuit: 65.95°
C (150.71°F)

Result

Proceed to

NG

A

OK (Checking from the PROBLEM SYMPTOMS TABLE)

B

OK (Checking from the DTC)

C

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra