AIR CONDITIONING SYSTEM, Diagnostic DTC:B1468/68

DESCRIPTION

• *1: for LHD

• *2: for RHD

The cooler thermistor (rear room temperature sensor RH*1 or LH*2) 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 cooler thermistor (rear room temperature sensor 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 cooler thermistor (rear room temperature sensor RH*1 or LH*2) and reads voltage changes as changes in the resistance of the cooler thermistor (rear room temperature sensor RH*1 or LH*2).

WIRING DIAGRAM

1. for LHD:

   

   *a	TSET
   *b	Cooler Thermistor (Rear Room Temperature Sensor RH)
   *c	Air Conditioning Amplifier Assembly

2. for RHD:

   

   *a	Cooler Thermistor (Rear Room Temperature Sensor LH)
   *b	Air Conditioning Amplifier Assembly

PROCEDURE

1. READ VALUE USING GTS (ROOM TEMPERATURE SENSOR [RP])

   
   

   • *1: for LHD

   • *2: for RHD

   
   

   1. Use the Data List to check if the cooler thermistor (rear room temperature sensor RH*1 or LH*2) is functioning properly Click here.

      Air Conditioner

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

      OK
      The display is as specified in the normal condition.

   
   

   OK

   REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

   NG

2. INSPECT COOLER THERMISTOR (REAR ROOM TEMPERATURE SENSOR [for Front Passenger Side])

   
   

   1. Remove the cooler thermistor (rear room temperature sensor RH*1 or LH*2) Click here

   2. Inspect the cooler thermistor (rear room temperature sensor RH*1 or LH*2) Click here.

   
   

   NG

   REPLACE COOLER THERMISTOR (REAR ROOM TEMPERATURE SENSOR [for Front Passenger Side]) Click here

   OK

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

   
   

   1. for LHD:

      
      

      1. Disconnect the z37 cooler thermistor (rear room temperature sensor RH) connector.

      2. Disconnect the E35 air conditioning amplifier assembly connector.

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

         Standard Resistance
         Tester Connection Condition Specified Condition z37-2 - E35-33 (SG) Always Below 1 Ω z37-1 - E35-22 (TSET) Always Below 1 Ω z37-1 - z37-2 Always 10 kΩ or higher z37-2 or E35-33 (SG) - Body ground Always 10 kΩ or higher z37-1 or E35-22 (TSET) - Body ground Always 10 kΩ or higher

   2. for RHD:

      
      

      1. Disconnect the z38 cooler thermistor (rear room temperature sensor LH) connector.

      2. Disconnect the E35 air conditioning amplifier connector.

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

         Standard Resistance
         Tester Connection Condition Specified Condition z38-2 - E35-33 (SG) Always Below 1 Ω z38-1 - E35-21 (TR) Always Below 1 Ω z38-1 - z38-2 Always 10 kΩ or higher z38-2 or E35-33 (SG) - Body ground Always 10 kΩ or higher z38-1 or E35-21 (TR) - Body ground Always 10 kΩ or higher

   
   

   OK

   REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR