Lexus NX: Glass Humidity Sensor Circuit (B14AA)
DESCRIPTION
The air conditioning thermistor assembly (glass humidity sensor) detects cabin humidity. The voltage of the air conditioning thermistor assembly (glass humidity sensor) changes in accordance with cabin humidity. The air conditioning amplifier assembly reads the changes in output voltage of the air conditioning thermistor assembly (glass humidity sensor).
The glass humidity sensor is integrated with the air conditioning thermistor assembly.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Memory | Note |
|---|---|---|---|---|---|
| B14AA | Glass Humidity Sensor Circuit | Open or short in glass humidity sensor circuit |
| Memorized (4 seconds or more)* | - |
- *: The air conditioning amplifier assembly stores this DTC if the malfunction has occurred for the period of time indicated in the brackets.
WIRING DIAGRAM
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CAUTION / NOTICE / HINT
HINT:
The air conditioning thermistor assembly must be replaced if the glass humidity sensor is malfunctioning.
PROCEDURE
| 1. | READ VALUE USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Air Conditioner / Data List.
(e) Check the value(s) by referring to the table below.
Body Electrical > Air Conditioner > Data List| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| Glass Humidity | Glass humidity | Min.: 0.00% Max.: 100.00% | Actual glass humidity is displayed | - |
| Tester Display |
|---|
| Glass Humidity |
OK:
The display is as specified in the normal condition column.
| OK | .gif) | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
|
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| 2. | CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY |
| (a) Disconnect the air conditioning thermistor assembly (glass humidity sensor) connector. |
|
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
| T13-5 (S5V) - Body ground | Power switch off | Below 1 V |
| T13-5 (S5V) - Body ground | Power switch on (IG) | 4.75 to 5.25 V |
| NG | | GO TO STEP 4 |
|
| 3. | INSPECT AIR CONDITIONING THERMISTOR ASSEMBLY (GLASS HUMIDITY SENSOR) |
(a) Inspect the air conditioning thermistor assembly (glass humidity sensor) connector.
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| NG | | REPLACE AIR CONDITIONING THERMISTOR ASSEMBLY (GLASS TEMPERATURE SENSOR) |
|
| 4. | CHECK HARNESS AND CONNECTOR (AIR CONDITIONING THERMISTOR ASSEMBLY [GLASS HUMIDITY SENSOR] - AIR CONDITIONING AMPLIFIER ASSEMBLY) |
(a) Disconnect the T13 air conditioning thermistor assembly (glass humidity sensor) connector.
(b) Disconnect the I50 air conditioning amplifier assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| T13-3 (RH) - I50-28 (RH) | Always | Below 1 Ω |
| T13-1 (SEG3) - I50-35 (SG-5) | Always | Below 1 Ω |
| T13-5 (S5V) - I50-31 (S5-4) | Always | Below 1 Ω |
| T13-3 (RH) or I50-28 (RH) - Body ground | Always | 10 kΩ or higher |
| T13-1 (SEG3) or I50-35 (SG-5) - Body ground | Always | 10 kΩ or higher |
| T13-5 (S5V) or I50-31 (S5-4) - Body ground | Always | 10 kΩ or higher |
| OK | | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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