AIR CONDITIONING SYSTEM, Diagnostic DTC:B14AA

DTC Code DTC Name
B14AA Glass Humidity Sensor Circuit

DESCRIPTION

The air conditioning amplifier assembly detects the windshield glass humidity from this circuit. The air conditioning amplifier assembly applies voltage to the air conditioning thermistor assembly (glass humidity sensor). As the humidity rises, the voltage output of the sensor increases. The air conditioning amplifier assembly detects the voltage change as the humidity changes.

DTC No. DTC Detection Condition Trouble Area
B14AA Open or short in glass humidity sensor circuit

  • Wire harness or connector

  • Air conditioning thermistor assembly (glass humidity sensor)

  • Air conditioning amplifier assembly

Tech Tips

The whole air conditioning thermistor assembly should be replaced if the glass humidity sensor is malfunctioning.

WIRING DIAGRAM

A003W7RE06

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
      Glass Humidity

      Glass humidity/

      Min.: 0 (%)

      Max.: 200 (%)

      		 Actual glass humidity 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 AIR CONDITIONING AMPLIFIER ASSEMBLY


    1. A003V5HE04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Air Conditioning Thermistor Assembly (Glass Humidity Sensor))

      Disconnect the T11 air conditioning thermistor assembly (glass humidity sensor) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      T11-5 (S5V) - Body ground Power switch on (IG) 4.5 to 5.5 V

    NG

    CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - GLASS HUMIDITY SENSOR) Click here

    OK

  3. INSPECT AIR CONDITIONING THERMISTOR ASSEMBLY (GLASS HUMIDITY SENSOR)


    1. A003XNBE03
      Text in Illustration
      *a Heat Conduction Sheet Part
      *b

      Component with harness connected

      (Air Conditioning Thermistor Assembly (Glass Humidity Sensor))
      *c Voltage (V)
      *d Relative Humidity (%)

      Remove the air conditioning thermistor assembly (glass humidity sensor) with the connector still connected Click here.

    2. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      T11-1 (SEG3) - T11-3 (RH)

      Power switch on (IG)

      Humidity is 5 to 15%

      		 Approximately 1.01 V
      T11-1 (SEG3) - T11-3 (RH)

      Power switch on (IG)

      Humidity is 15 to 25%

      		 Approximately 1.37 V
      T11-1 (SEG3) - T11-3 (RH)

      Power switch on (IG)

      Humidity is 25 to 35%

      		 Approximately 1.73 V
      T11-1 (SEG3) - T11-3 (RH)

      Power switch on (IG)

      Humidity is 35 to 45%

      		 Approximately 2.09 V
      T11-1 (SEG3) - T11-3 (RH)

      Power switch on (IG)

      Humidity is 45 to 55%

      		 Approximately 2.45 V
      T11-1 (SEG3) - T11-3 (RH)

      Power switch on (IG)

      Humidity is 55 to 65%

      		 Approximately 2.81 V
      T11-1 (SEG3) - T11-3 (RH)

      Power switch on (IG)

      Humidity is 65 to 75%

      		 Approximately 3.17 V
      T11-1 (SEG3) - T11-3 (RH)

      Power switch on (IG)

      Humidity is 75 to 85%

      		 Approximately 3.53 V
      T11-1 (SEG3) - T11-3 (RH)

      Power switch on (IG)

      Humidity is 85 to 95%

      		 Approximately 3.89 V

      Note


      • Do not touch the sensor as body heat will affect the inspection results. When performing the inspection, hold the sensor by its connector.

      • Allow the sensor to acclimate to the ambient temperature and humidity before performing the inspection.

      • The specified voltages in the table above are based on inspections performed when the ambient temperature is 25°C (77°F).

      Tech Tips

      As the humidity increases, the voltage increases (see the graph).


    NG

    REPLACE AIR CONDITIONING THERMISTOR ASSEMBLY Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - GLASS HUMIDITY SENSOR)


    1. Disconnect the T11 air conditioning thermistor assembly (glass humidity sensor) connector.

    2. Disconnect the H85 and H86 air conditioning amplifier assembly connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      T11-3 (RH) - H85-28 (RH) Always Below 1 Ω
      T11-3 (RH) - Body ground Always 10 kΩ or higher
      T11-1 (SEG3) - H86-7 (LBLO) Always Below 1 Ω
      T11-1 (SEG3) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

  5. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - GLASS HUMIDITY SENSOR)


    1. Disconnect the T11 air conditioning thermistor assembly (glass humidity sensor) connector.

    2. Disconnect the H85 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
      T11-5 (S5V) - H85-31 (S5-4) Always Below 1 Ω
      T11-5 (S5V) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here