AIR CONDITIONING SYSTEM (for Manual Air Conditioning System), Diagnostic DTC:B1412/12

DESCRIPTION

The ambient temperature sensor is installed in front of the condenser.

The air conditioning amplifier applies a voltage (5 V) to the ambient temperature sensor and reads voltage changes as changes in the resistance of the ambient temperature sensor.

INSPECTION PROCEDURE

PROCEDURE

1. Click here

   READ VALUE USING INTELLIGENT TESTER (AMBI TEMP SENS)

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the ignition switch on (IG) and turn the intelligent tester main switch on.

   3. Select the item below in the Data List, and read the value displayed on the intelligent tester.

      Table 1. Data List / Air Conditioner:

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      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 circuit: -23.3°C (-9.94°F) Short 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 (Checking from PROBLEM SYMPTOMS TABLE) B OK (Checking from DTC) C

   
   
   • AClick here
   • BClick here
   • CClick here
2. Click here

   INSPECT AMBIENT TEMPERATURE SENSOR

   
   
   1. 

      Remove the ambient temperature sensor (Click here).

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

      Standard resistance

      Tester Connection Condition Specified Condition A7-1 - A7-2 10°C (50°F) 3.00 to 3.73 kΩ A7-1 - A7-2 15°C (50°F) 2.45 to 2.88 kΩ A7-1 - A7-2 20°C (68°F) 1.95 to 2.30 kΩ A7-1 - A7-2 25°C (77°F) 1.60 to 1.80 kΩ A7-1 - A7-2 30°C (86°F) 1.28 to 1.47 kΩ A7-1 - A7-2 35°C (95°F) 1.00 to 1.22 kΩ A7-1 - A7-2 40°C (104°F) 0.80 to 1.00 kΩ A7-1 - A7-2 45°C (113°F) 0.65 to 0.85 kΩ A7-1 - A7-2 50°C (122°F) 0.50 to 0.70 kΩ A7-1 - A7-2 55°C (131°F) 0.44 to 0.60 kΩ A7-1 - A7-2 60°C (140°F) 0.36 to 0.50 kΩ

      Note:
      

      • Touching the sensor even slightly 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.

      Tip:

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

   
   
   • OKClick here
   • NGClick here
3. Click here

   CHECK HARNESS AND CONNECTOR (AMBIENT TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER)

   
   
   1. 

      Disconnect the A7 sensor connector.

   2. Disconnect the D33 amplifier connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition A7-1 - D33-5 (TAM) Always Below 1 Ω A7-2 - D33-13 (SG-2) Always Below 1 Ω D33-5 (TAM) - Body ground Always 10 kΩ or higher D33-13 (SG-2) - Body ground Always 10 kΩ or higher

   
   
   • OKClick here
   • NGClick here
4. Click here

   REPLACE AIR CONDITIONING AMPLIFIERClick here

5. Click here

   REPAIR OR REPLACE HARNESS OR CONNECTOR

6. Click here

   REPLACE AMBIENT TEMPERATURE SENSORClick here

7. Click here

   REPLACE AIR CONDITIONING AMPLIFIERClick here

8. Click here

   PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLEClick here