AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System), Diagnostic DTC:B1417/17

DESCRIPTION

The No. 2 cooler thermistor is installed on the evaporator in the rear air conditioning unit to detect the cooled air temperature that has passed through the evaporator and control the air conditioning. It sends appropriate signals to the air conditioning amplifier assembly. The resistance of the No. 2 cooler thermistor changes in accordance with the cooled air temperature that has passed through the rear evaporator. 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 No. 2 cooler thermistor and reads voltage changes as the resistance of the No. 2 cooler thermistor changes. This sensor is used for frost prevention.

PROCEDURE

1. Click here

   READ VALUE USING INTELLIGENT TESTER (NO. 2 COOLER THERMISTOR)

   
   

   1. Use the Data List to check if the No. 2 cooler thermistor is functioning properly.

      Table 2. Air Conditioner

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      Ambient Temp Sens (Rear)	No. 2 cooler thermistor / Min.: -29.7°C (-21.46°F) Max.: 59.55°C (139.19°F)	Actual rear evaporator temperature displayed	Open in the circuit: -29.7°C (-21.46°F). Short in the circuit: 59.55°C (139.19°F).

      OK
      The display is as specified in the normal condition.

   
   
   • OK

     REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (Click here)

   • NGClick here
2. Click here

   INSPECT NO. 2 COOLER THERMISTOR

   
   

   1. Remove the No. 2 air conditioning harness assembly (Click here).

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

      Standard Resistance
      Tester Connection Condition Specified Condition 7 (-) - 8 (+) -10°C (14°F) 7.40 to 9.20 kΩ -5°C (23°F) 5.65 to 7.00 kΩ 0°C (32°F) 4.35 to 5.40 kΩ 5°C (41°F) 3.40 to 4.20 kΩ 10°C (50°F) 2.68 to 3.30 kΩ 15°C (59°F) 2.10 to 2.60 kΩ 20°C (68°F) 1.66 to 2.10 kΩ 25°C (77°F) 1.32 to 1.66 kΩ 30°C (86°F) 1.05 to 1.35 kΩ

      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.

      Tip:

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

   
   
   • OKClick here
   • NG

     REPLACE NO. 2 AIR CONDITIONING HARNESS ASSEMBLY (Click here)

3. Table 3. *1 Front view of wire harness connector: (to No. 2 Air Conditioning Harness Assembly) *2 Rear view of wire harness connector: (to Air Conditioning Amplifier Assembly)
   Click here

   CHECK HARNESS AND CONNECTOR (NO. 2 AIR CONDITIONING HARNESS - AIR CONDITIONING AMPLIFIER)

   
   

   1. Disconnect the K19 No. 2 air conditioning harness connector.

   2. Disconnect the E35 amplifier connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition K19-8 (+) - E35-17 (TEC) Always Below 1 Ω K19-7 (-) - E35-1 (SG) Always Below 1 Ω E35-17 (TEC) - Body ground Always 10 kΩ or higher E35-1 (SG) - Body ground Always 10 kΩ or higher

   
   
   • OKClick here
   • NG

     REPAIR OR REPLACE HARNESS OR CONNECTOR

4. Click here

   CHECK NO. 2 AIR CONDITIONING HARNESS ASSEMBLY (OPERATION)

   
   

   1. Replace the No. 2 air conditioning harness assembly with a normal one and check that the condition returns to normal (Click here).

   
   
   • NEXTClick here
5. Click here

   CHECK FOR DTC

   
   

   1. Clear the DTCs (Click here).

   2. Check for DTCs (Click here).

      OK
      DTC B1417 is not output.

   
   
   • OK

     REPLACE NO. 2 AIR CONDITIONING HARNESS ASSEMBLY (Click here)

   • NG

     REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (Click here)