Dtc B1412/12 Ambient Temperature Sensor Circuit

Heater & Air Conditioning System. Camry. Acv40 Gsv40
Air Conditioning. Camry. Acv40 Gsv40

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING INTELLIGENT TESTER

INSPECT AIR CONDITIONING AMPLIFIER

INSPECT AMBIENT TEMPERATURE SENSOR

CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - A/C AMPLIFIER)

DTC B1412/12 Ambient Temperature Sensor Circuit


DESCRIPTION

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 A/C amplifier and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the A/C 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 A/C amplifier applies voltage (5 V) to the ambient temperature sensor and reads voltage changes as the resistance of the ambient temperature sensor changes.

DTC No.
DTC Detection Condition
Trouble Area
B1412/12
Open or short in ambient temperature sensor circuit
  1. Ambient temperature sensor
  2. Harness or connector between ambient temperature sensor and A/C amplifier
  3. A/C amplifier

WIRING DIAGRAM


Camry. Acv40 Gsv40.Air Conditioning.Air Conditioning System. Dtc B1412/12 Ambient Temperature Sensor Circuit


INSPECTION PROCEDURE

1.READ VALUE USING INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to the ON position and turn 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
Ambient Temp Sensor
(Ambi Temp Sens)
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)
OK:
The display is as specified in the normal condition column.

Result:

Result
Proceed to
NG
A
OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE)
B
OK (When troubleshooting according to the DTC)
C


B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE AIR CONDITIONING AMPLIFIER
A


2.INSPECT AIR CONDITIONING AMPLIFIER


    Camry. Acv40 Gsv40.Air Conditioning.Air Conditioning System. Dtc B1412/12 Ambient Temperature Sensor Circuit

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

  1. Turn the ignition switch to the ON position.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    E38-5 (TAM) - E38-13 (SG-2)
    		Ignition switch: ON
    at 25°C (77°F)
    		1.35 to 1.75 V
    E38-5 (TAM) - E38-13 (SG-2)
    		Ignition switch: ON
    at 40°C (104°F)
    		0.9 to 1.2 V
    HINT:
    As the temperature increases, the voltage decreases.
    Result:
    Result
    		Proceed to
    NG
    		A
    OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE)
    		B
    OK (When troubleshooting according to the DTC)
    		C


B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE AIR CONDITIONING AMPLIFIER
A


3.INSPECT AMBIENT TEMPERATURE SENSOR


    Camry. Acv40 Gsv40.Air Conditioning.Air Conditioning System. Dtc B1412/12 Ambient Temperature Sensor Circuit

  1. Remove the ambient temperature sensor.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A2-1 - A2-2
    		10°C (50°F)
    		3.00 to 3.73 kΩ
    A2-1 - A2-2
    		15°C (59°F)
    		2.45 to 2.88 kΩ
    A2-1 - A2-2
    		20°C (68°F)
    		1.95 to 2.30 kΩ
    A2-1 - A2-2
    		25°C (77°F)
    		1.60 to 1.80 kΩ
    A2-1 - A2-2
    		30°C (86°F)
    		1.28 to 1.47 kΩ
    A2-1 - A2-2
    		35°C (95°F)
    		1.00 to 1.22 kΩ
    A2-1 - A2-2
    		40°C (104°F)
    		0.80 to 1.00 kΩ
    A2-1 - A2-2
    		45°C (113°F)
    		0.65 to 0.85 kΩ
    A2-1 - A2-2
    		50°C (122°F)
    		0.50 to 0.70 kΩ
    A2-1 - A2-2
    		55°C (131°F)
    		0.44 to 0.60 kΩ
    A2-1 - A2-2
    		60°C (140°F)
    		0.36 to 0.50 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 AMBIENT TEMPERATURE SENSOR
OK


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


    Camry. Acv40 Gsv40.Air Conditioning.Air Conditioning System. Dtc B1412/12 Ambient Temperature Sensor Circuit

  1. Disconnect the ambient temperature sensor connector.



    Camry. Acv40 Gsv40.Air Conditioning.Air Conditioning System. Dtc B1412/12 Ambient Temperature Sensor Circuit

  1. Disconnect the A/C amplifier connector.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A2-2 - E38-5 (TAM)
    		Always
    		Below 1 Ω
    A2-1 - E38-13 (SG-2)
    		Always
    		Below 1 Ω
    E38-5 (TAM) - Body ground
    		Always
    		10 kΩ or higher
    E38-13 (SG-2) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER