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DTC    B14AA    Glass Humidity Sensor Circuit

for Preparation Click here


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
  1. Wire harness or connector
  2. Air conditioning thermistor assembly (glass humidity sensor)
  3. Air conditioning amplifier assembly

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


WIRING DIAGRAM


E222434E06


INSPECTION PROCEDURE

1.READ VALUE USING INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the intelligent tester on.

  1. Enter the following menus: Body / Air Conditioner / Data List.

  1. 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


    E109024E04

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

  1. 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

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Air Conditioning Thermistor Assembly (Glass Humidity Sensor))



NG
Go to step 5
OK


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


    E208909E03

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

  1. Turn the power switch on (IG).

  1. 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

    NOTICE:
    1. Do not touch the sensor as body heat will affect the inspection results. When performing the inspection, hold the sensor by its connector.
    2. Allow the sensor to acclimate to the ambient temperature and humidity before performing the inspection.
    3. The specified voltages in the table above are based on inspections performed when the ambient temperature is 25°C (77°F).

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

    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 (%)



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.

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

  1. 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.

  1. Disconnect the H85 air conditioning amplifier assembly connector.

  1. 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)