AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System), Diagnostic DTC:B1411/11

DESCRIPTION

The room temperature sensor (cooler thermistor) is installed in the instrument panel to detect the cabin temperature which is used to control the heater and air conditioning system AUTO mode. The resistance of the room temperature sensor (cooler thermistor) 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 a voltage (5 V) to the room temperature sensor (cooler thermistor) and reads voltage changes due to changes in the resistance of the room temperature sensor (cooler thermistor).

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM

   1. Connect the Techstream to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the Techstream on.

   4. Enter the following menus: Body Electrical / 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	Cooler thermistor (room temperature sensor) / min.: -6.50°C (20.30°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 (COOLER THERMISTOR)

   1. Remove the room temperature sensor (cooler thermistor) Click here.

   2. Disconnect the I57 room temperature sensor (cooler thermistor) connector.

      

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

      Standard Resistance

      Tester Connection Condition Specified Condition I57-1 (+)- I57-2 (-) 10°C (50°F) 3.00 to 3.73 kΩ I57-1 (+)- I57-2 (-) 15°C (59°F) 2.45 to 2.88 kΩ I57-1 (+)- I57-2 (-) 20°C (68°F) 1.95 to 2.30 kΩ I57-1 (+)- I57-2 (-) 25°C (77°F) 1.60 to 1.80 kΩ I57-1 (+)- I57-2 (-) 30°C (86°F) 1.28 to 1.47 kΩ I57-1 (+)- I57-2 (-) 35°C (95°F) 1.00 to 1.22 kΩ I57-1 (+)- I57-2 (-) 40°C (104°F) 0.80 to 1.00 kΩ I57-1 (+)- I57-2 (-) 45°C (113°F) 0.65 to 0.85 kΩ I57-1 (+)- I57-2 (-) 50°C (122°F) 0.50 to 0.70 kΩ I57-1 (+)- I57-2 (-) 55°C (131°F) 0.44 to 0.60 kΩ I57-1 (+)- I57-2 (-) 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).

      Text in Illustration

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

   NG

   REPLACE ROOM TEMPERATURE SENSOR (COOLER THERMISTOR) Click here

   OK

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

   1. Disconnect the I77 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 I77-29 (TR) - I57-1 (+) Always Below 1 Ω I77-34 (SG-1) - I57-2 (-) Always Below 1 Ω I77-29 (TR) - Body ground Always 10 kΩ or higher I77-34 (SG-1) - Body ground Always 10 kΩ or higher

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

   REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here