HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): B141A15; Room Temperature Sensor Circuit Short to Battery or Open; 2023 - 2025 MY Corolla Corolla HV [09/2022

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM1000000026Z3U
Model Year Start: 2023	Model: Corolla	Prod Date Range: [09/2022 - ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): B141A15; Room Temperature Sensor Circuit Short to Battery or Open; 2023 - 2025 MY Corolla Corolla HV [09/2022 - ]

DTC

B141A15

Room Temperature Sensor Circuit Short to Battery or Open

DESCRIPTION

The room temp. sensor (cooler 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 room temp. sensor (cooler 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 to the room temp. sensor (cooler thermistor) and reads voltage changes due to changes in the resistance of the room temp. sensor (cooler thermistor).

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

B141A15

Room Temperature Sensor Circuit Short to Battery or Open

Diagnosis Condition:

Ignition switch ON

Malfunction:

Open or short (+B) in room temperature sensor circuit

Detection Time:

Continuously for 4 seconds or more

Room temp. sensor (cooler thermistor)
Harness or connector
Air conditioning amplifier assembly

Memorized

DTC Detection Condition Combination Table

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	Ignition switch ON	○	○
Malfunction	Open in room temperature sensor circuit	○	-
Malfunction	Short (+B) in room temperature sensor circuit	-	○
Detection Time		Continuously for 4 seconds or more	Continuously for 4 seconds or more
Trip Count		1 trip	1 trip

HINT:

If the conditions of either of these patterns are detected, a DTC will be stored.

WIRING DIAGRAM

PROCEDURE

1.	CHECK ROOM TEMP. SENSOR (COOLER THERMISTOR) CIRCUIT

(a) Disconnect the I36 room temp. sensor (cooler thermistor) connector.

*a	Front view of wire harness connector (to Room Temp. Sensor (Cooler Thermistor))

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
I36-1 - Body ground	Ignition switch ON	0 to 5.5 V

GO TO STEP 5

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Air Conditioner > Clear DTCs

3.	CHECK FOR DTC

(a) Turn the ignition switch off.

(b) Disconnect the I36 room temp. sensor (cooler thermistor) connector.

*a	Front view of wire harness connector (to Room Temp. Sensor (Cooler Thermistor))

*1	Room Temp. Sensor (Cooler Thermistor)
*2	Air Conditioning Amplifier Assembly

(d) Turn the ignition switch to ON and wait for 4 seconds or more.

(e) Check for DTCs.

Body Electrical > Air Conditioner > Trouble Codes

Result	Proceed to
B141A11 is output	A
B141A15 is output	B

REPLACE ROOM TEMP. SENSOR (COOLER THERMISTOR)

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

(a) Disconnect the I36 room temp. sensor (cooler thermistor) connector.

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

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

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

(a) Disconnect the I36 room temp. sensor (cooler thermistor) connector.

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

Standard Resistance:

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

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR