AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System), Diagnostic DTC:B1468/68

DESCRIPTION

The rear room temperature sensor RH*1 or LH*2 (for front passenger side) is installed in the rear quarter trim board RH*1 or LH*2 to detect the rear room temperature and control the heater and air conditioner "auto" mode. The resistance of the rear room temperature sensor RH*1 or LH*2 changes in accordance with the rear room temperature for RH*1 or LH*2 seat. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning amplifier applies a voltage (5 V) to the rear room temperature sensor RH*1 or LH*2 and reads voltage changes as changes in the resistance of the rear room temperature sensor RH*1 or LH*2.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING INTELLIGENT TESTER (AIR CONDITIONER)

   
   

   1. Use the Data List to check if the rear room temperature sensor RH*1 or LH*2 is functioning properly.

      Air Conditioner

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      Room Temperature Sensor (RP)	Rear room temperature sensor for RH*1 or LH*2 / Min.: -6.5°C (20.3°F) Max.: 57.25°C (135.05°F)	Actual rear room temperature for RH*1 or LH*2 displayed	Open in the circuit: -6.5°C (20.3°F). Short in the circuit: 57.25°C (135.05°F).

      Tech Tips

      *1: for LHD

      *2: for RHD

      OK
      The display is as specified in the normal condition.

   
   

   NG

   INSPECT REAR ROOM TEMPERATURE SENSOR Click here

   OK

   REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

2. INSPECT REAR ROOM TEMPERATURE SENSOR

   

   
   

   1. for LHD

      Remove the rear room temperature sensor RH Click here.

   2. for RHD

      Remove the rear room temperature sensor LH Click here.

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

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

      Note

      Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.

      Tech Tips

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

      Result

      Result	Proceed to
      OK	A
      NG (for LHD)	B
      NG (for RHD)	C

   
   

   B

   REPLACE REAR ROOM TEMPERATURE SENSOR RH Click here

   C

   REPLACE REAR ROOM TEMPERATURE SENSOR LH Click here

   A

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

   

   
   

   1. 

      for LHD

      
      

      1. Disconnect the z56 sensor 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 z56-2 (-)- E35-2 (SG-6) Always Below 1 Ω z56-1 (+) - E35-19 (TR7) E35-2 (SG-6) - Body ground Always 10 kΩ or higher E35-19 (TR7) - Body ground

   2. for RHD

      
      

      1. Disconnect the z55 sensor 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 z55-2 (-) - E35-2 (SG-6) Always Below 1 Ω z55-1 (+) - E35-18 (TR) E35-2 (SG-6) - Body ground Always 10 kΩ or higher E35-18 (TR) - Body ground

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

   REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here