B1462

AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1462: Room Humidity Sensor Circuit

DTC B1462 - Room Humidity Sensor Circuit

DESCRIPTION

The room humidity sensor detects room humidity. The voltage of the room humidity sensor changes in accordance with room humidity. The air conditioning amplifier reads changes in the room humidity sensor.
The room humidity sensor is integrated with room temperature sensor.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM
(a) Connect Techstream to DLC3.
(b) Turn the power switch ON (IG) and turn Techstream ON.
(c) Select the item below in the Data List, and read the display on Techstream.

Air conditioning amplifier

OK:
The displayed is as specified in the normal condition.

Result

C -- REPLACE AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.

2. CHECK AIR CONDITIONING AMPLIFIER (RH VOLTAGE)

(a) Remove the air conditioning amplifier with connectors still connected.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:

HINT: As the temperature increases, the voltage decreases.

Result

C -- REPLACE AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.

3. INSPECT ROOM TEMPERATURE SENSOR (HUMIDITY SENSOR)

(a) Remove the room temperature sensor.
(b) Measure the voltage of the sensor.
Standard voltage:
at 25°C (77°F) Humidity 40%: 1.61 to 2.24 V
at 25°C (77°F) Humidity 60%: 2.26 to 2.66 V
HINT: As the humidity increases, the voltage increases (see the graph).

NG -- REPLACE ROOM TEMPERATURE SENSOR
OK -- Continue to next step.

4. CHECK WIRE HARNESS (ROOM HUMIDITY SENSOR - AIR CONDITIONING AMPLIFIER)

(a) Disconnect the A9 sensor connector.
(b) Disconnect the A7 amplifier connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:

NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE AIR CONDITIONING AMPLIFIER