AIR CONDITIONING SYSTEM, Diagnostic DTC:B1411/11

DESCRIPTION

The room temperature sensor is installed in the instrument panel. It detects the cabin temperature to control air conditioning AUTO mode. The resistance of the room temperature sensor changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning amplifier assembly 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 appropriate signals to the air conditioning amplifier assembly.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING INTELLIGENT TESTER

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the power switch on (IG).

   3. Turn the intelligent tester on.

   4. Enter the following menus: Body / Air Conditioner / Data List.

   5. Check the value(s) by referring to the table below.

      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 cabin temperature displayed	-

      OK
      The display is as specified in the Normal Condition column.

      Result
      Result Proceed to NG A OK (When troubleshooting according to Problem Symptoms Table) B OK (When troubleshooting according to the DTC) C

   
   

   B

   PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

   C

   REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

   A

2. INSPECT ROOM TEMPERATURE SENSOR

   
   
   1. 

      Text in Illustration

      *a	Component without harness connected (Room Temperature Sensor)
      *b	Sensing Portion
      *c	Resistance (kΩ)
      *d	Allowable Range
      *e	Temperature (°C (°F))

      Remove the room temperature sensor.

   2. Disconnect the H79 room temperature sensor connector.

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

      Standard Resistance

      Tester Connection Condition Specified Condition H79-1 (+) - H79-2 (-) 10°C (50°F) 3.00 to 3.73 kΩ H79-1 (+) - H79-2 (-) 15°C (59°F) 2.45 to 2.88 kΩ H79-1 (+) - H79-2 (-) 20°C (68°F) 1.95 to 2.30 kΩ H79-1 (+) - H79-2 (-) 25°C (77°F) 1.60 to 1.80 kΩ H79-1 (+) - H79-2 (-) 30°C (86°F) 1.28 to 1.47 kΩ H79-1 (+) - H79-2 (-) 35°C (95°F) 1.00 to 1.22 kΩ H79-1 (+) - H79-2 (-) 40°C (104°F) 0.80 to 1.00 kΩ H79-1 (+) - H79-2 (-) 45°C (113°F) 0.65 to 0.85 kΩ H79-1 (+) - H79-2 (-) 50°C (122°F) 0.50 to 0.70 kΩ H79-1 (+) - H79-2 (-) 55°C (131°F) 0.44 to 0.60 kΩ H79-1 (+) - H79-2 (-) 60°C (140°F) 0.36 to 0.50 kΩ

      Note

      
      

      • Hold the sensor only by its connector. Touching the sensor may change the resistance value.

      • When measuring, the sensor temperature must be the same as the ambient temperature.

      Tech Tips

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

   
   

   NG

   REPLACE ROOM TEMPERATURE SENSOR Click here

   OK

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

   
   

   1. Disconnect the H85 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition H85-29 (TR) - H79-1 (+) Always Below 1 Ω H85-34 (SG-1) - H79-2 (-) Always Below 1 Ω H85-29 (TR) - Body ground Always 10 kΩ or higher H85-34 (SG-1) - Body ground Always 10 kΩ or higher

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

   REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here