Room Temperature Sensor Circuit (B1411/11)

DESCRIPTION

The room temperature sensor is installed in the instrument panel. It detects the cabin temperature to control the air conditioning AUTO mode. The resistance of the room temperature sensor changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The A/C amplifier applies voltage (5 V) to the room temperature sensor and reads voltage changes as the resistance of the room temperature sensor changes. This sensor also sends appropriate signals to the A/C amplifier.

DTC No.	DTC Detection condition	Trouble Area
B1411/11	Open or short in room temperature sensor circuit	Room temperature sensor Harness or connector between room temperature sensor and A/C amplifier A/C amplifier

WIRING DIAGRAM
PROCEDURE

1. READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Body / Air Conditioner / Data List.

(e) Check the value(s) by referring to the table below.

Air Conditioner

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Room Temperature Sensor	Room temperature sensor / Min.: -6.5 °C Max.: 57 °C	Actual cabin temperature displayed	-

OK:

The display is as specified in the Normal Condition column.

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

C

REPLACE A/C AMPLIFIER

A

1. INSPECT ROOM TEMPERATURE SENSOR

(a) Remove the room temperature sensor.

(b) Disconnect the room temperature sensor connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
D11-1 - D11-2	10 °C	3.00 to 3.73 kΩ
D11-1 - D11-2	15 °C	2.45 to 2.88 kΩ
D11-1 - D11-2	20 °C	1.95 to 2.30 kΩ
D11-1 - D11-2	25 °C	1.60 to 1.80 kΩ
D11-1 - D11-2	30 °C	1.28 to 1.47 kΩ
D11-1 - D11-2	35 °C	1.00 to 1.22 kΩ
D11-1 - D11-2	40 °C	0.80 to 1.00 kΩ
D11-1 - D11-2	45 °C	0.65 to 0.85 kΩ
D11-1 - D11-2	50 °C	0.50 to 0.70 kΩ
D11-1 - D11-2	55 °C	0.44 to 0.60 kΩ
D11-1 - D11-2	60 °C	0.36 to 0.50 kΩ

NOTICE:

• Hold the sensor only by its connector. Touching the sensor may change the resistance value.
• When measuring, the sensor temperature must be the same as the ambient temperature.

HINT:

As the temperature increases, the resistance decreases (see the graph).

Text in Illustration

*1	Component without harness connected (Room Temperature Sensor)
*2	Sensing Portion

NG

REPLACE ROOM TEMPERATURE SENSOR

OK

1. CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - A/C AMPLIFIER)

(a) Disconnect the A/C amplifier connector.

(b) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition D47-29 (TR) - D11-1 Always Below 1 Ω D47-34 (SG-1) - D11-2 Always Below 1 Ω D47-29 (TR) - Body ground Always 10 kΩ or higher D47-34 (SG-1) - Body ground Always 10 kΩ or higher Text in Illustration *1 Front view of wire harness connector (to A/C Amplifier) *2 Front view of wire harness connector (to Room Temperature Sensor)

OK

REPLACE A/C AMPLIFIER

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR