DTC 19

AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System): B1419/19: Rear Room Temperature Sensor Circuit

DTC B1419/19 - Rear Room Temperature Sensor Circuit

DESCRIPTION

The rear room temperature sensor is installed in the rear panel to detect the rear room temperature and control the heater and air conditioning AUTO mode. The resistance of the rear room temperature sensor changes in accordance with the rear room temperature. 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 rear room temperature sensor and reads voltage changes as changes in the resistance of the rear room temperature sensor.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

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

Data List / Air Conditioner





OK:
The display is as specified in the normal condition column.
Result:






C -- REPLACE AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.
2. INSPECT REAR ROOM TEMPERATURE SENSOR




(a) Remove the rear room temperature sensor Removal.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NOTICE:
- Touching the sensor even slightly may change the resistance value. Be sure to hold the connector of the sensor.
- When measuring, the sensor temperature must be the same as the ambient temperature.
HINT: As the temperature increases, the resistance decreases (see the graph).

NG -- REPLACE REAR ROOM TEMPERATURE SENSOR
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (REAR ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER)




(a) Disconnect the N13 sensor connector.
(b) Disconnect the D38 amplifier connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






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