HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (except TMC Made, and Gasoline Model, with Automatic Air Conditioning System): B1411; Room Temperature Sensor Circuit; 2023 MY Corolla Corolla Hatchback GR Corolla [09/2022

Last Modified: 05-13-2024	6.11:8.1.0	Doc ID: RM1000000025R23
Model Year Start: 2023	Model: GR Corolla	Prod Date Range: [09/2022 - 11/2022]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (except TMC Made, and Gasoline Model, with Automatic Air Conditioning System): B1411; Room Temperature Sensor Circuit; 2023 MY Corolla Corolla Hatchback GR Corolla [09/2022 - 11/2022]

DTC

B1411

Room Temperature Sensor Circuit

DESCRIPTION

The cooler (room temp. sensor) thermistor is installed in the instrument panel to detect the cabin temperature, which is used to control the air conditioning system. The resistance of the cooler (room temp. sensor) thermistor changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning amplifier assembly applies voltage (5 V) to the cooler (room temp. sensor) thermistor and reads voltage changes due to changes in the resistance of the cooler (room temp. sensor) thermistor.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

B1411

Room Temperature Sensor Circuit

Open or short in room temperature sensor circuit

Cooler (room temp. sensor) thermistor
Harness or connector
Air conditioning amplifier assembly

Memorized

(4 sec. or more)*

*: The air conditioning amplifier assembly stores this DTC if the malfunction has occurred for the period of time indicated in the brackets.

HINT:

If the cabin temperature is approximately -18.6°C (-1.48°F) or lower, DTC B1411 may be stored even though the system is normal.

WIRING DIAGRAM

PROCEDURE

1.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

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

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Room Temperature Sensor

Cooler (room temp. sensor) thermistor

Min.: -6.50°C (20.30°F)

Max.: 57.25°C (135.05°F)

Actual cabin temperature displayed

Cooler (room temp. sensor) thermistor circuit malfunction

When open circuit: -6.50°C (20.30°F)
When short circuit: 57.25°C (135.05°F)

Body Electrical > Air Conditioner > Data List

Tester Display
Room Temperature Sensor

OK:

The display is as specified in the normal condition column.

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

2.	INSPECT COOLER (ROOM TEMP. SENSOR) THERMISTOR

(a) Remove the cooler (room temp. sensor) thermistor.

Click here

(b) Inspect the cooler (room temp. sensor) thermistor.

Click here

REPLACE COOLER (ROOM TEMP. SENSOR) THERMISTOR

3.	CHECK HARNESS AND CONNECTOR (COOLER (ROOM TEMP. SENSOR) THERMISTOR - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the I48 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
I36-1 - I48-5 (TR)	Always	Below 1 Ω
I36-2 - I48-3 (SG-1)	Always	Below 1 Ω
I36-1 or I48-5 (TR) - Other terminals and body ground	Always	10 kΩ or higher
I36-2 or I48-3 (SG-1) - Other terminals and body ground	Always	10 kΩ or higher

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR